diff --git a/.gitignore b/.gitignore
index 854ac21..dd69fbd 100644
--- a/.gitignore
+++ b/.gitignore
@@ -50,3 +50,6 @@ next-env.d.ts
 
 # Uploaded Belege (persistent volume in production)
 data/documents/
+
+.vscode/
+.react-router
diff --git a/.playwright-mcp/console-2026-05-02T20-43-04-874Z.log b/.playwright-mcp/console-2026-05-02T20-43-04-874Z.log
new file mode 100644
index 0000000..eb0e894
--- /dev/null
+++ b/.playwright-mcp/console-2026-05-02T20-43-04-874Z.log
@@ -0,0 +1 @@
+[     421ms] [ERROR] Failed to load resource: the server responded with a status of 404 (Not Found) @ http://localhost:3000/favicon.ico:0
diff --git a/.playwright-mcp/page-2026-05-02T20-43-05-337Z.yml b/.playwright-mcp/page-2026-05-02T20-43-05-337Z.yml
new file mode 100644
index 0000000..19949f3
--- /dev/null
+++ b/.playwright-mcp/page-2026-05-02T20-43-05-337Z.yml
@@ -0,0 +1,19 @@
+- generic [ref=e4]:
+  - generic [ref=e5]:
+    - img [ref=e7]
+    - generic [ref=e9]: Rechnungsmanager
+  - generic [ref=e10]:
+    - heading "Willkommen zurück" [level=1] [ref=e11]
+    - paragraph [ref=e12]: Benutzername oder E-Mail und Passwort eingeben
+  - generic [ref=e14]:
+    - generic [ref=e15]:
+      - text: Benutzername oder E-Mail
+      - textbox "Benutzername oder E-Mail" [ref=e16]:
+        - /placeholder: anna oder anna@example.de
+    - generic [ref=e17]:
+      - text: Passwort
+      - generic [ref=e18]:
+        - textbox "Passwort" [ref=e19]
+        - button "Passwort anzeigen" [ref=e20]:
+          - img [ref=e21]
+    - button "Anmelden" [ref=e24]
\ No newline at end of file
diff --git a/INTEGRATION_EXAMPLE.md b/INTEGRATION_EXAMPLE.md
new file mode 100644
index 0000000..8157a7b
--- /dev/null
+++ b/INTEGRATION_EXAMPLE.md
@@ -0,0 +1,95 @@
+/**
+ * INTEGRATION EXAMPLE: How to use error logging in your existing routes
+ * This shows the new error-logger.server in real-world usage
+ */
+
+// Before (old code - minimal logging):
+/*
+export async function action({ request }: { request: Request }) {
+  const user = await getApiUser(request);
+  if (!user) return Response.json({ error: "Unauthorized" }, { status: 401 });
+
+  const body = await request.json();
+  const parsed = customerSchema.safeParse(body);
+  if (!parsed.success) return Response.json({ error: parsed.error.issues }, { status: 400 });
+
+  try {
+    const customer = await prisma.customer.create({ data: parsed.data });
+    await log({ userId: user.id, action: "CREATE_CUSTOMER", entity: "Customer", entityId: customer.id, request });
+    return Response.json(customer, { status: 201 });
+  } catch (error) {
+    console.error(error);  // ❌ Not helpful for debugging
+    return Response.json({ error: "Internal server error" }, { status: 500 });
+  }
+}
+*/
+
+// After (with comprehensive error logging):
+import { getApiUser } from "@/session.server";
+import prisma from "@/lib/prisma.server";
+import { log } from "@/lib/logger.server";
+import { logApiError } from "@/lib/error-logger.server";
+import { customerSchema } from "@/lib/schemas";
+
+export async function action({ request }: { request: Request }) {
+  const user = await getApiUser(request);
+  if (!user) return Response.json({ error: "Unauthorized" }, { status: 401 });
+
+  try {
+    const body = await request.json();
+    const parsed = customerSchema.safeParse(body);
+    if (!parsed.success) {
+      return Response.json({ error: parsed.error.issues }, { status: 400 });
+    }
+
+    const customer = await prisma.customer.create({ data: parsed.data });
+    await log({
+      userId: user.id,
+      action: "CREATE_CUSTOMER",
+      entity: "Customer",
+      entityId: customer.id,
+      request,
+    });
+    return Response.json(customer, { status: 201 });
+  } catch (error) {
+    // ✅ Now with full context: stack trace, request details, metadata
+    logApiError(error, {
+      request,
+      endpoint: "/api/customers",
+      userId: user.id,
+      statusCode: 500,
+      metadata: {
+        method: request.method,
+      },
+    });
+    return Response.json({ error: "Internal server error" }, { status: 500 });
+  }
+}
+
+// ============================================================================
+// WHAT YOU'LL SEE IN THE SERVER LOGS NOW:
+// ============================================================================
+
+/*
+================================================================================
+[API_ERROR] | 2026-05-02T22:15:45.789Z | duplicate entry for unique field 'email'
+POST /api/customers | user: user-abc123 | ip: 192.168.1.100 | endpoint: /api/customers | statusCode: 500
+Error: Customer with email 'john@example.com' already exists
+    at Object.create (file:///app/lib/customer.server.ts:25:13)
+    at action (file:///app/routes/api.customers.ts:30:7)
+    at processRequest (file:///app/routes/_middleware.ts:12:3)
+
+Metadata: {
+  "method": "POST",
+  "endpoint": "/api/customers"
+}
+================================================================================
+
+✓ You can now see:
+  - Exact error message with context
+  - HTTP method & endpoint
+  - User ID & IP address
+  - Stack trace for debugging
+  - Custom metadata
+  - Timestamp
+*/
diff --git a/app/components/company/company-form.tsx b/app/components/company/company-form.tsx
index 1080593..9761614 100644
--- a/app/components/company/company-form.tsx
+++ b/app/components/company/company-form.tsx
@@ -4,6 +4,8 @@ import { z } from "zod";
 import { Button } from "@/components/ui/button";
 import { Input } from "@/components/ui/input";
 import { Label } from "@/components/ui/label";
+import { debugLog, handleApiError } from "@/lib/client-validation";
+import { useState, useEffect } from "react";
 
 const schema = z.object({
   name: z.string().min(1, "Name ist erforderlich"),
@@ -32,118 +34,317 @@ interface CompanyFormProps {
   submitLabel?: string;
 }
 
-function Field({ label, error, children }: { label: string; error?: string; children: React.ReactNode }) {
+function Field({ 
+  label, 
+  error, 
+  tooltip, 
+  required = false,
+  children 
+}: { 
+  label: string; 
+  error?: string; 
+  tooltip?: string;
+  required?: boolean;
+  children: React.ReactNode 
+}) {
+  const [showRequiredTooltip, setShowRequiredTooltip] = useState(false);
+
+  // Debug: log errors to console
+  if (error) {
+    console.log(`[Field Error] ${label}: ${error}`);
+  }
+  
   return (
     <div className="space-y-1.5">
-      <Label>{label}</Label>
-      {children}
-      {error && <p className="text-xs text-red-600">{error}</p>}
+      <Label className="flex items-center gap-1">
+        {label}
+        {required && (
+          <span className="inline-flex items-center group relative">
+            <span className="text-red-500 font-bold text-lg leading-none">*</span>
+            <div 
+              className="absolute bottom-full left-1/2 -translate-x-1/2 mb-2 px-2 py-1 bg-red-600 text-white text-xs rounded whitespace-nowrap opacity-0 group-hover:opacity-100 transition-opacity pointer-events-none"
+            >
+              Erforderliches Feld
+            </div>
+          </span>
+        )}
+      </Label>
+      <div className="relative">
+        <div className={required && !error ? "relative" : ""}>
+          {children}
+        </div>
+        {/* Show error tooltip ONLY when there's an error */}
+        {error && (
+          <div className="mt-2 p-2 bg-red-50 border border-red-200 rounded text-xs text-red-700 flex gap-2">
+            <svg className="h-4 w-4 text-red-500 flex-shrink-0 mt-0.5" fill="currentColor" viewBox="0 0 20 20">
+              <path fillRule="evenodd" d="M18 10a8 8 0 11-16 0 8 8 0 0116 0zm-7-4a1 1 0 11-2 0 1 1 0 012 0zM9 9a1 1 0 000 2v3a1 1 0 001 1h1a1 1 0 100-2v-3a1 1 0 00-1-1H9z" clipRule="evenodd" />
+            </svg>
+            <div>
+              <p className="font-medium">{error}</p>
+              {tooltip && <p className="text-red-600 mt-0.5">{tooltip}</p>}
+            </div>
+          </div>
+        )}
+      </div>
     </div>
   );
 }
 
 export function CompanyForm({ defaultValues, onSubmit, submitLabel = "Speichern" }: CompanyFormProps) {
-  const { register, handleSubmit, formState: { errors, isSubmitting } } = useForm<FormData>({
+  const [apiError, setApiError] = useState<string | null>(null);
+  const [validationError, setValidationError] = useState<string | null>(null);
+  const { register, handleSubmit, formState: { errors, isSubmitting, isValid }, watch, trigger } = useForm<FormData>({
     resolver: zodResolver(schema),
+    mode: "onBlur", // Validate when user leaves field
     defaultValues: { country: "DE", invoicePrefix: "RE", kleinunternehmer: false, ...defaultValues },
   });
 
+  // Debug: log all errors
+  useEffect(() => {
+    if (Object.keys(errors).length > 0) {
+      console.log("[Form Errors]", errors);
+    }
+  }, [errors]);
+
+  // Watch form data for debug logging
+  const formData = watch();
+
+  const handleFormSubmit = async (data: FormData) => {
+    // Trigger validation to check if form is actually valid
+    const isFormValid = await trigger();
+    
+    if (!isFormValid) {
+      // Build error message from validation errors
+      const errorFields: string[] = [];
+      
+      if (errors.name) errorFields.push("Firmenname");
+      if (errors.address) errorFields.push("Adresse");
+      if (errors.zip) errorFields.push("Postleitzahl");
+      if (errors.city) errorFields.push("Ort/Stadt");
+      if (errors.email) errorFields.push("E-Mail");
+      if (errors.taxId) errorFields.push("Steuernummer");
+      if (errors.vatId) errorFields.push("USt-IdNr.");
+      if (errors.bankIban) errorFields.push("IBAN");
+      if (errors.bankBic) errorFields.push("BIC");
+      
+      const fieldList = errorFields.length > 0 
+        ? errorFields.join(", ")
+        : "Bitte überprüfen Sie die rot gekennzeichneten Felder";
+      
+      const message = `Folgende Felder sind erforderlich oder falsch: ${fieldList}`;
+      setValidationError(message);
+      debugLog("warning", "Form validation failed", { errors: errorFields });
+      return;
+    }
+    
+    try {
+      setApiError(null);
+      setValidationError(null);
+      debugLog("info", "Submitting form", data);
+      
+      await onSubmit(data);
+      
+      debugLog("success", "Form submitted successfully");
+    } catch (error) {
+      debugLog("error", "Form submission failed", error);
+      handleApiError(error, "/api/companies");
+      
+      // Extract error message for user
+      if (error instanceof Response) {
+        try {
+          const json = await error.clone().json();
+          const messages = json.error?.map?.((e: any) => e.message)?.join(", ") || 
+                          json.message ||
+                          "Ein Fehler ist aufgetreten";
+          setApiError(messages);
+        } catch {
+          setApiError(`HTTP ${error.status}: ${error.statusText}`);
+        }
+      } else if (error instanceof Error) {
+        setApiError(error.message);
+      } else {
+        setApiError("Ein unbekannter Fehler ist aufgetreten");
+      }
+    }
+  };
+
   return (
-    <form onSubmit={handleSubmit(onSubmit)} className="space-y-6">
-      <div>
-        <h3 className="text-sm font-semibold text-gray-700 uppercase tracking-wide mb-3">Stammdaten</h3>
-        <div className="grid grid-cols-1 md:grid-cols-2 gap-4">
-          <Field label="Firmenname *" error={errors.name?.message}>
-            <Input {...register("name")} placeholder="Muster GmbH" />
-          </Field>
-          <Field label="Rechtsform" error={errors.legalForm?.message}>
-            <Input {...register("legalForm")} placeholder="GmbH, AG, UG..." />
-          </Field>
-          <Field label="Steuernummer" error={errors.taxId?.message}>
-            <Input {...register("taxId")} placeholder="123/456/78901" />
-          </Field>
-          <Field label="USt-IdNr." error={errors.vatId?.message}>
-            <Input {...register("vatId")} placeholder="DE123456789" />
-          </Field>
-        </div>
+    <form onSubmit={handleSubmit(handleFormSubmit)} className="space-y-6">
+      {/* Required fields info banner */}
+      <div className="p-4 bg-blue-50 border border-blue-200 rounded-lg">
+        <p className="text-sm font-medium text-blue-900">ℹ️ Erforderliche Felder</p>
+        <p className="text-sm text-blue-800 mt-1">Folgende Felder sind erforderlich: <strong>Firmenname, Adresse, Postleitzahl, Ort</strong></p>
       </div>
 
-      <div>
-        <h3 className="text-sm font-semibold text-gray-700 uppercase tracking-wide mb-3">Anschrift</h3>
-        <div className="grid grid-cols-1 md:grid-cols-2 gap-4">
-          <div className="md:col-span-2">
-            <Field label="Straße & Hausnummer *" error={errors.address?.message}>
-              <Input {...register("address")} placeholder="Musterstraße 1" />
+      {/* Validation error banner */}
+      {validationError && (
+          <div className="p-4 bg-yellow-50 border border-yellow-200 rounded-lg">
+            <p className="text-sm font-medium text-yellow-900">⚠️ Eingabefehler</p>
+            <p className="text-sm text-yellow-800 mt-1">{validationError}</p>
+          </div>
+        )}
+
+        {/* API error banner */}
+        {apiError && (
+          <div className="p-4 bg-red-50 border border-red-200 rounded-lg">
+            <p className="text-sm font-medium text-red-800">❌ Fehler</p>
+            <p className="text-sm text-red-700 mt-1">{apiError}</p>
+          </div>
+        )}
+        <div>
+          <h3 className="text-sm font-semibold text-gray-700 uppercase tracking-wide mb-3">Stammdaten</h3>
+          <div className="grid grid-cols-1 md:grid-cols-2 gap-4">
+            <Field 
+              label="Firmenname" 
+              required={true}
+              error={errors.name?.message}
+              tooltip="Name des Unternehmens oder der Geschäftseinheit"
+            >
+              <Input {...register("name")} placeholder="Muster GmbH" />
+            </Field>
+            <Field 
+              label="Rechtsform" 
+              error={errors.legalForm?.message}
+              tooltip="z.B. GmbH, AG, UG, Einzelunternehmen"
+            >
+              <Input {...register("legalForm")} placeholder="GmbH, AG, UG..." />
+            </Field>
+            <Field 
+              label="Steuernummer" 
+              error={errors.taxId?.message}
+              tooltip="10-stellige deutsche Steuernummer (z.B. 123/456/78901)"
+            >
+              <Input {...register("taxId")} placeholder="123/456/78901" />
+            </Field>
+            <Field 
+              label="USt-IdNr." 
+              error={errors.vatId?.message}
+              tooltip="Umsatzsteuer-Identifikationsnummer (z.B. DE123456789)"
+            >
+              <Input {...register("vatId")} placeholder="DE123456789" />
             </Field>
           </div>
-          <Field label="PLZ *" error={errors.zip?.message}>
-            <Input {...register("zip")} placeholder="10115" />
-          </Field>
-          <Field label="Ort *" error={errors.city?.message}>
+        </div>
+
+        <div>
+          <h3 className="text-sm font-semibold text-gray-700 uppercase tracking-wide mb-3">Anschrift</h3>
+          <div className="grid grid-cols-1 md:grid-cols-2 gap-4">
+            <div className="md:col-span-2">
+              <Field 
+                label="Straße & Hausnummer" 
+                required={true}
+                error={errors.address?.message}
+                tooltip="Vollständige Adresse mit Straße und Hausnummer"
+              >
+                <Input {...register("address")} placeholder="Musterstraße 1" />
+              </Field>
+            </div>
+            <Field 
+              label="PLZ" 
+              required={true}
+              error={errors.zip?.message}
+              tooltip="Deutsche Postleitzahl (5-stellig)"
+            >
+              <Input {...register("zip")} placeholder="10115" />
+            </Field>
+            <Field 
+              label="Ort" 
+              required={true}
+              error={errors.city?.message}
+              tooltip="Stadt oder Gemeinde"
+            >
             <Input {...register("city")} placeholder="Berlin" />
-          </Field>
-        </div>
-      </div>
-
-      <div>
-        <h3 className="text-sm font-semibold text-gray-700 uppercase tracking-wide mb-3">Kontakt</h3>
-        <div className="grid grid-cols-1 md:grid-cols-2 gap-4">
-          <Field label="E-Mail" error={errors.email?.message}>
-            <Input {...register("email")} type="email" placeholder="info@firma.de" />
-          </Field>
-          <Field label="Telefon" error={errors.phone?.message}>
-            <Input {...register("phone")} placeholder="+49 30 12345678" />
-          </Field>
-          <Field label="Website" error={errors.website?.message}>
-            <Input {...register("website")} placeholder="https://firma.de" />
-          </Field>
-        </div>
-      </div>
-
-      <div>
-        <h3 className="text-sm font-semibold text-gray-700 uppercase tracking-wide mb-3">Bankverbindung</h3>
-        <div className="grid grid-cols-1 md:grid-cols-2 gap-4">
-          <div className="md:col-span-2">
-            <Field label="IBAN" error={errors.bankIban?.message}>
-              <Input {...register("bankIban")} placeholder="DE89 3704 0044 0532 0130 00" />
             </Field>
           </div>
-          <Field label="BIC" error={errors.bankBic?.message}>
-            <Input {...register("bankBic")} placeholder="COBADEFFXXX" />
-          </Field>
-          <Field label="Kreditinstitut" error={errors.bankName?.message}>
-            <Input {...register("bankName")} placeholder="Commerzbank" />
-          </Field>
         </div>
-      </div>
 
-      <div>
-        <h3 className="text-sm font-semibold text-gray-700 uppercase tracking-wide mb-3">Rechnungseinstellungen</h3>
-        <div className="grid grid-cols-1 md:grid-cols-2 gap-4">
-          <Field label="Rechnungsnummern-Präfix" error={errors.invoicePrefix?.message}>
-            <Input {...register("invoicePrefix")} placeholder="RE" />
-          </Field>
+        <div>
+          <h3 className="text-sm font-semibold text-gray-700 uppercase tracking-wide mb-3">Kontakt</h3>
+          <div className="grid grid-cols-1 md:grid-cols-2 gap-4">
+            <Field 
+              label="E-Mail" 
+              error={errors.email?.message}
+              tooltip="Kontakt-E-Mail-Adresse (optional)"
+            >
+              <Input {...register("email")} type="email" placeholder="info@firma.de" />
+            </Field>
+            <Field 
+              label="Telefon" 
+              error={errors.phone?.message}
+              tooltip="Telefonnummer mit Landesvorwahl (optional)"
+            >
+              <Input {...register("phone")} placeholder="+49 30 12345678" />
+            </Field>
+            <Field 
+              label="Website" 
+              error={errors.website?.message}
+              tooltip="URL der Unternehmenswebseite (optional)"
+            >
+              <Input {...register("website")} placeholder="https://firma.de" />
+            </Field>
+          </div>
         </div>
-        <p className="text-xs text-gray-500 mt-1">Format: {"{Präfix}"}-{"{Jahr}"}-{"{Nummer}"} z.B. RE-2024-001</p>
-        <div className="mt-4">
-          <label className="flex items-center gap-2 cursor-pointer select-none">
-            <input
-              type="checkbox"
-              {...register("kleinunternehmer")}
-              className="h-4 w-4 rounded border-gray-300"
-            />
-            <span className="text-sm text-gray-700">
-              Kleinunternehmer (§19 UStG) — keine Umsatzsteuer
-            </span>
-          </label>
-        </div>
-      </div>
 
-      <div className="flex justify-end pt-2">
-        <Button type="submit" disabled={isSubmitting}>
-          {isSubmitting ? "Speichern..." : submitLabel}
-        </Button>
-      </div>
-    </form>
+        <div>
+          <h3 className="text-sm font-semibold text-gray-700 uppercase tracking-wide mb-3">Bankverbindung</h3>
+          <div className="grid grid-cols-1 md:grid-cols-2 gap-4">
+            <div className="md:col-span-2">
+              <Field 
+                label="IBAN" 
+                error={errors.bankIban?.message}
+                tooltip="Internationale Kontonummer (z.B. DE89 3704 0044...) (optional)"
+              >
+                <Input {...register("bankIban")} placeholder="DE89 3704 0044 0532 0130 00" />
+              </Field>
+            </div>
+            <Field 
+              label="BIC" 
+              error={errors.bankBic?.message}
+              tooltip="Bank Identifier Code (z.B. COBADEFFXXX) (optional)"
+            >
+              <Input {...register("bankBic")} placeholder="COBADEFFXXX" />
+            </Field>
+            <Field 
+              label="Kreditinstitut" 
+              error={errors.bankName?.message}
+              tooltip="Name der Bank (optional)"
+            >
+              <Input {...register("bankName")} placeholder="Commerzbank" />
+            </Field>
+          </div>
+        </div>
+
+        <div>
+          <h3 className="text-sm font-semibold text-gray-700 uppercase tracking-wide mb-3">Rechnungseinstellungen</h3>
+          <div className="grid grid-cols-1 md:grid-cols-2 gap-4">
+            <Field 
+              label="Rechnungsnummern-Präfix" 
+              error={errors.invoicePrefix?.message}
+              tooltip="Präfix für Rechnungsnummern (z.B. RE oder INV)"
+            >
+              <Input {...register("invoicePrefix")} placeholder="RE" />
+            </Field>
+          </div>
+          <p className="text-xs text-gray-500 mt-1">Format: {"{Präfix}"}-{"{Jahr}"}-{"{Nummer}"} z.B. RE-2024-001</p>
+          <div className="mt-4">
+            <label className="flex items-center gap-2 cursor-pointer select-none">
+              <input
+                type="checkbox"
+                {...register("kleinunternehmer")}
+                className="h-4 w-4 rounded border-gray-300"
+              />
+              <span className="text-sm text-gray-700">
+                Kleinunternehmer (§19 UStG) — keine Umsatzsteuer
+              </span>
+            </label>
+          </div>
+        </div>
+
+        <div className="flex justify-end gap-3 pt-2">
+          <Button type="submit" disabled={isSubmitting || !isValid}>
+            {isSubmitting ? "Speichern..." : submitLabel}
+          </Button>
+        </div>
+      </form>
   );
 }
diff --git a/app/components/debug-panel.tsx b/app/components/debug-panel.tsx
new file mode 100644
index 0000000..d4e4cfa
--- /dev/null
+++ b/app/components/debug-panel.tsx
@@ -0,0 +1,116 @@
+/**
+ * Debug panel component - shows in development and when debug mode is enabled
+ * Access via browser console: setDebugMode(true) or localStorage.setItem('DEBUG_MODE', 'true')
+ */
+
+import { useEffect, useState } from "react";
+import { isDebugMode, setDebugMode } from "@/lib/client-validation";
+
+export function DebugPanel() {
+  const [isOpen, setIsOpen] = useState(false);
+  const [debugEnabled, setDebugEnabled] = useState(false);
+
+  useEffect(() => {
+    setDebugEnabled(isDebugMode());
+  }, []);
+
+  const toggleDebug = () => {
+    const newState = !debugEnabled;
+    setDebugMode(newState);
+    setDebugEnabled(newState);
+  };
+
+  // Only show in development
+  if (process.env.NODE_ENV !== "development") {
+    return null;
+  }
+
+  return (
+    <>
+      {/* Floating button */}
+      <button
+        onClick={() => setIsOpen(!isOpen)}
+        className={`fixed bottom-4 right-4 z-40 w-12 h-12 rounded-full font-bold text-white text-lg transition-all ${
+          debugEnabled
+            ? "bg-blue-600 hover:bg-blue-700"
+            : "bg-gray-400 hover:bg-gray-500"
+        }`}
+        title={debugEnabled ? "Debug Mode: ON" : "Debug Mode: OFF"}
+      >
+        🐛
+      </button>
+
+      {/* Debug panel */}
+      {isOpen && (
+        <div className="fixed bottom-20 right-4 z-40 bg-gray-900 text-white rounded-lg shadow-2xl p-4 w-80 max-h-96 overflow-auto">
+          <div className="space-y-3">
+            <div className="flex items-center justify-between">
+              <h3 className="font-bold text-lg">Debug Mode</h3>
+              <button
+                onClick={() => setIsOpen(false)}
+                className="text-gray-400 hover:text-white"
+              >
+                ✕
+              </button>
+            </div>
+
+            <div className="border-t border-gray-700 pt-3">
+              <label className="flex items-center gap-2 cursor-pointer">
+                <input
+                  type="checkbox"
+                  checked={debugEnabled}
+                  onChange={toggleDebug}
+                  className="w-4 h-4"
+                />
+                <span className="text-sm">
+                  {debugEnabled ? "✅ Enabled" : "⭕ Disabled"}
+                </span>
+              </label>
+            </div>
+
+            <div className="bg-gray-800 p-3 rounded text-xs space-y-1">
+              <p className="text-gray-400">Browser Console Commands:</p>
+              <code className="block text-blue-400">
+                setDebugMode(true)
+              </code>
+              <code className="block text-blue-400">
+                localStorage.setItem('DEBUG_MODE', 'true')
+              </code>
+              <code className="block text-green-400">
+                isDebugMode()
+              </code>
+            </div>
+
+            <div className="bg-gray-800 p-3 rounded text-xs">
+              <p className="text-gray-400 mb-1">Current State:</p>
+              <p className="text-yellow-300">
+                DEBUG: <strong>{debugEnabled ? "ON" : "OFF"}</strong>
+              </p>
+              <p className="text-yellow-300">
+                ENV: <strong>{process.env.NODE_ENV}</strong>
+              </p>
+            </div>
+
+            <button
+              onClick={() => {
+                if (debugEnabled) {
+                  console.log("🔍 Debug Info:");
+                  console.log({
+                    url: window.location.href,
+                    userAgent: navigator.userAgent,
+                    timestamp: new Date().toISOString(),
+                  });
+                } else {
+                  alert("Enable Debug Mode first!");
+                }
+              }}
+              className="w-full bg-blue-600 hover:bg-blue-700 px-3 py-2 rounded text-sm font-medium"
+            >
+              Log Debug Info
+            </button>
+          </div>
+        </div>
+      )}
+    </>
+  );
+}
diff --git a/app/components/ui/tooltip.tsx b/app/components/ui/tooltip.tsx
new file mode 100644
index 0000000..71fc4ef
--- /dev/null
+++ b/app/components/ui/tooltip.tsx
@@ -0,0 +1,28 @@
+import * as React from "react"
+import * as TooltipPrimitive from "@radix-ui/react-tooltip"
+
+import { cn } from "@/lib/utils"
+
+const TooltipProvider = TooltipPrimitive.Provider
+
+const Tooltip = TooltipPrimitive.Root
+
+const TooltipTrigger = TooltipPrimitive.Trigger
+
+const TooltipContent = React.forwardRef<
+  React.ElementRef<typeof TooltipPrimitive.Content>,
+  React.ComponentPropsWithoutRef<typeof TooltipPrimitive.Content>
+>(({ className, sideOffset = 4, ...props }, ref) => (
+  <TooltipPrimitive.Content
+    ref={ref}
+    sideOffset={sideOffset}
+    className={cn(
+      "z-50 overflow-hidden rounded-md border border-slate-200 bg-white px-3 py-1.5 text-sm text-slate-950 shadow-md animate-in fade-in-0 zoom-in-95 data-[state=closed]:animate-out data-[state=closed]:fade-out-0 data-[state=closed]:zoom-out-95 data-[side=bottom]:slide-in-from-top-2 data-[side=left]:slide-in-from-right-2 data-[side=right]:slide-in-from-left-2 data-[side=top]:slide-in-from-bottom-2 dark:border-slate-800 dark:bg-slate-950 dark:text-slate-50",
+      className
+    )}
+    {...props}
+  />
+))
+TooltipContent.displayName = TooltipPrimitive.Content.displayName
+
+export { Tooltip, TooltipTrigger, TooltipContent, TooltipProvider }
diff --git a/app/entry.server.tsx b/app/entry.server.tsx
index 5075f22..2efa593 100644
--- a/app/entry.server.tsx
+++ b/app/entry.server.tsx
@@ -1,4 +1,6 @@
 import { startCleanupScheduler } from "./lib/cleanup.server";
+import { initializeDatabase } from "./lib/db-init.server";
+import { logStartupError, logError } from "./lib/error-logger.server";
 import { PassThrough } from "node:stream";
 import type { AppLoadContext, EntryContext } from "react-router";
 import { createReadableStreamFromReadable } from "@react-router/node";
@@ -8,6 +10,12 @@ import { renderToPipeableStream } from "react-dom/server";
 
 startCleanupScheduler();
 
+// Initialize database: run migrations on startup
+initializeDatabase().catch((error) => {
+  logStartupError(error);
+  process.exit(1);
+});
+
 const ABORT_DELAY = 5_000;
 
 export default function handleRequest(
@@ -38,11 +46,20 @@ export default function handleRequest(
           pipe(body);
         },
         onShellError(error: unknown) {
+          logError("SHELL_ERROR", error, {
+            request,
+            route: new URL(request.url).pathname,
+          });
           reject(error);
         },
         onError(error: unknown) {
           responseStatusCode = 500;
-          if (shellRendered) console.error(error);
+          if (shellRendered) {
+            logError("RENDER_ERROR", error, {
+              request,
+              route: new URL(request.url).pathname,
+            });
+          }
         },
       }
     );
diff --git a/app/lib/ERROR_LOGGING_GUIDE.md b/app/lib/ERROR_LOGGING_GUIDE.md
new file mode 100644
index 0000000..0237526
--- /dev/null
+++ b/app/lib/ERROR_LOGGING_GUIDE.md
@@ -0,0 +1,136 @@
+/**
+ * Error Logging Usage Examples
+ * 
+ * Use these patterns in your routes to get better error debugging
+ */
+
+// ============================================================================
+// PATTERN 1: In a loader (data fetching)
+// ============================================================================
+
+import { json, type LoaderFunction } from "react-router";
+import { logRouteError } from "@/lib/error-logger.server";
+import prisma from "@/lib/prisma.server";
+
+export const loader: LoaderFunction = async ({ request, params }) => {
+  try {
+    const company = await prisma.company.findUnique({
+      where: { id: params.id },
+    });
+
+    if (!company) {
+      throw new Error(`Company not found: ${params.id}`);
+    }
+
+    return json({ company });
+  } catch (error) {
+    logRouteError(error, {
+      request,
+      route: request.url,
+      userId: params.userId, // if available
+      metadata: {
+        companyId: params.id,
+      },
+    });
+    throw error; // Re-throw to let React Router handle it
+  }
+};
+
+// ============================================================================
+// PATTERN 2: In an action (mutation/form submission)
+// ============================================================================
+
+import { logActionError } from "@/lib/error-logger.server";
+
+export const action: LoaderFunction = async ({ request, params }) => {
+  try {
+    const formData = await request.formData();
+    const result = await prisma.company.update({
+      where: { id: params.id },
+      data: { name: formData.get("name") },
+    });
+    return json({ success: true, result });
+  } catch (error) {
+    logActionError(error, {
+      request,
+      action: "UPDATE_COMPANY",
+      metadata: {
+        companyId: params.id,
+        method: request.method,
+      },
+    });
+    throw error;
+  }
+};
+
+// ============================================================================
+// PATTERN 3: In an API route (POST/PUT/DELETE)
+// ============================================================================
+
+import { logApiError } from "@/lib/error-logger.server";
+
+export const action: LoaderFunction = async ({ request }) => {
+  try {
+    const data = await request.json();
+    
+    // Validate
+    if (!data.name) {
+      return json(
+        { error: "Name is required" },
+        { status: 400 }
+      );
+    }
+
+    // Process
+    const result = await prisma.company.create({ data });
+    return json({ success: true, result }, { status: 201 });
+  } catch (error) {
+    logApiError(error, {
+      request,
+      endpoint: "/api/companies",
+      statusCode: 500,
+      metadata: {
+        method: request.method,
+      },
+    });
+    return json(
+      { error: "Internal server error" },
+      { status: 500 }
+    );
+  }
+};
+
+// ============================================================================
+// PATTERN 4: Database operations with error context
+// ============================================================================
+
+import { logDatabaseError } from "@/lib/error-logger.server";
+
+async function fetchCompanyWithUsers(companyId: string) {
+  try {
+    return await prisma.company.findUnique({
+      where: { id: companyId },
+      include: { users: true },
+    });
+  } catch (error) {
+    logDatabaseError(error, "company.findUnique", {
+      metadata: { companyId },
+    });
+    throw error;
+  }
+}
+
+// ============================================================================
+// OUTPUT EXAMPLE (Server Console)
+// ============================================================================
+
+/*
+================================================================================
+[ROUTE_ERROR] | 2026-05-02T22:10:30.123Z | Company not found | route: /companies/123 | GET /companies/123 | user: user-id-456
+Stack at Object.loader (file:///app/routes/companies.$id.tsx:12:13)
+    at process._tickCallback (internal/timers.ts:203:26)
+Metadata: {
+  "companyId": "123"
+}
+================================================================================
+*/
diff --git a/app/lib/client-validation.ts b/app/lib/client-validation.ts
new file mode 100644
index 0000000..9bedfca
--- /dev/null
+++ b/app/lib/client-validation.ts
@@ -0,0 +1,244 @@
+/**
+ * Client-side validation and debugging utilities
+ * Mirrors server-side validation for real-time user feedback
+ */
+
+// Debug mode - enable via localStorage: localStorage.setItem('DEBUG_MODE', 'true')
+export function isDebugMode(): boolean {
+  if (typeof window === "undefined") return false;
+  return localStorage.getItem("DEBUG_MODE") === "true";
+}
+
+export function setDebugMode(enabled: boolean): void {
+  if (typeof window === "undefined") return;
+  if (enabled) {
+    localStorage.setItem("DEBUG_MODE", "true");
+    console.log("✅ DEBUG MODE ENABLED");
+  } else {
+    localStorage.removeItem("DEBUG_MODE");
+    console.log("❌ DEBUG MODE DISABLED");
+  }
+}
+
+/**
+ * Log error to browser console (only in debug mode)
+ */
+export function debugLog(type: string, message: string, data?: unknown): void {
+  if (!isDebugMode()) return;
+
+  const style = {
+    error: "color: #ef4444; font-weight: bold;",
+    warning: "color: #f97316; font-weight: bold;",
+    info: "color: #3b82f6; font-weight: bold;",
+    success: "color: #22c55e; font-weight: bold;",
+  };
+
+  const typeStyle = style[type as keyof typeof style] || style.info;
+  console.log(`%c[${type.toUpperCase()}] ${message}`, typeStyle, data);
+}
+
+/**
+ * Validation error type
+ */
+export interface ValidationError {
+  field: string;
+  message: string;
+}
+
+/**
+ * Validate tax ID (Steuernummer): 10 digits
+ */
+export function validateTaxId(val: string | null | undefined): ValidationError | null {
+  if (!val || val === "") return null;
+  if (!/^\d{10}$/.test(val)) {
+    return { field: "taxId", message: "Steuernummer muss 10 Ziffern haben" };
+  }
+  return null;
+}
+
+/**
+ * Validate VAT ID (USt-IdNr): DE + 9 digits
+ */
+export function validateVatId(val: string | null | undefined): ValidationError | null {
+  if (!val || val === "") return null;
+  if (!/^DE\d{9}$/.test(val)) {
+    return { field: "vatId", message: "USt-IdNr. muss im Format DE + 9 Ziffern sein" };
+  }
+  return null;
+}
+
+/**
+ * Validate IBAN
+ */
+export function validateIban(val: string | null | undefined): ValidationError | null {
+  if (!val || val === "") return null;
+  if (!/^[A-Z]{2}\d{2}[A-Z0-9]{1,30}$/.test(val)) {
+    return { field: "bankIban", message: "Ungültige IBAN" };
+  }
+  return null;
+}
+
+/**
+ * Validate BIC
+ */
+export function validateBic(val: string | null | undefined): ValidationError | null {
+  if (!val || val === "") return null;
+  if (!/^[A-Z0-9]{8,11}$/.test(val)) {
+    return { field: "bankBic", message: "Ungültiger BIC" };
+  }
+  return null;
+}
+
+/**
+ * Validate website URL
+ */
+export function validateWebsite(val: string | null | undefined): ValidationError | null {
+  if (!val || val === "") return null;
+  if (!/^https?:\/\//.test(val)) {
+    return { field: "website", message: "Website muss mit http:// oder https:// beginnen" };
+  }
+  if (val.length > 255) {
+    return { field: "website", message: "Website darf maximal 255 Zeichen sein" };
+  }
+  return null;
+}
+
+/**
+ * Validate company form data
+ */
+export interface CompanyFormData {
+  name: string;
+  address: string;
+  zip: string;
+  city: string;
+  taxId?: string;
+  vatId?: string;
+  website?: string;
+  bankIban?: string;
+  bankBic?: string;
+  email?: string;
+  phone?: string;
+  legalForm?: string;
+  country?: string;
+  bankName?: string;
+}
+
+export function validateCompanyForm(
+  data: CompanyFormData
+): ValidationError[] {
+  const errors: ValidationError[] = [];
+
+  // Required fields
+  if (!data.name || data.name.trim() === "") {
+    errors.push({ field: "name", message: "Firmenname erforderlich" });
+  } else if (data.name.length > 255) {
+    errors.push({ field: "name", message: "Firmenname darf maximal 255 Zeichen sein" });
+  }
+
+  if (!data.address || data.address.trim() === "") {
+    errors.push({ field: "address", message: "Adresse erforderlich" });
+  } else if (data.address.length > 500) {
+    errors.push({ field: "address", message: "Adresse darf maximal 500 Zeichen sein" });
+  }
+
+  if (!data.zip || data.zip.trim() === "") {
+    errors.push({ field: "zip", message: "PLZ erforderlich" });
+  } else if (!/^[\d\s-]*$/.test(data.zip)) {
+    errors.push({ field: "zip", message: "PLZ darf nur Zahlen, Bindestriche und Leerzeichen enthalten" });
+  } else if (data.zip.length > 20) {
+    errors.push({ field: "zip", message: "PLZ darf maximal 20 Zeichen sein" });
+  }
+
+  if (!data.city || data.city.trim() === "") {
+    errors.push({ field: "city", message: "Stadt erforderlich" });
+  } else if (data.city.length > 100) {
+    errors.push({ field: "city", message: "Stadt darf maximal 100 Zeichen sein" });
+  }
+
+  // Optional fields with validation
+  if (data.taxId) {
+    const taxError = validateTaxId(data.taxId);
+    if (taxError) errors.push(taxError);
+  }
+
+  if (data.vatId) {
+    const vatError = validateVatId(data.vatId);
+    if (vatError) errors.push(vatError);
+  }
+
+  if (data.website) {
+    const webError = validateWebsite(data.website);
+    if (webError) errors.push(webError);
+  }
+
+  if (data.bankIban) {
+    const ibanError = validateIban(data.bankIban);
+    if (ibanError) errors.push(ibanError);
+  }
+
+  if (data.bankBic) {
+    const bicError = validateBic(data.bankBic);
+    if (bicError) errors.push(bicError);
+  }
+
+  if (data.email && data.email.trim()) {
+    if (!/^[^\s@]+@[^\s@]+\.[^\s@]+$/.test(data.email)) {
+      errors.push({ field: "email", message: "Ungültige E-Mail-Adresse" });
+    }
+  }
+
+  if (data.phone && data.phone.length > 20) {
+    errors.push({ field: "phone", message: "Telefonnummer darf maximal 20 Zeichen sein" });
+  }
+
+  if (data.legalForm && data.legalForm.length > 100) {
+    errors.push({ field: "legalForm", message: "Rechtsform darf maximal 100 Zeichen sein" });
+  }
+
+  if (data.country && data.country.length > 2) {
+    errors.push({ field: "country", message: "Ländercode darf maximal 2 Zeichen sein" });
+  }
+
+  if (data.bankName && data.bankName.length > 255) {
+    errors.push({ field: "bankName", message: "Bankname darf maximal 255 Zeichen sein" });
+  }
+
+  // Debug logging
+  if (errors.length > 0) {
+    debugLog("warning", `Validation failed: ${errors.length} error(s)`, errors);
+  } else {
+    debugLog("success", "Validation passed", data);
+  }
+
+  return errors;
+}
+
+/**
+ * Validate API response errors
+ */
+export function handleApiError(error: unknown, endpoint: string): void {
+  debugLog("error", `API Error from ${endpoint}`, error);
+
+  if (error instanceof Response) {
+    debugLog("error", `HTTP ${error.status}: ${error.statusText}`, error);
+  } else if (error instanceof Error) {
+    debugLog("error", error.message, error.stack);
+  } else {
+    debugLog("error", "Unknown error", error);
+  }
+}
+
+/**
+ * Get error message for a specific field
+ */
+export function getFieldError(field: string, errors: ValidationError[]): string | null {
+  const error = errors.find((e) => e.field === field);
+  return error?.message || null;
+}
+
+/**
+ * Check if field has error
+ */
+export function hasFieldError(field: string, errors: ValidationError[]): boolean {
+  return errors.some((e) => e.field === field);
+}
diff --git a/app/lib/db-init.server.ts b/app/lib/db-init.server.ts
new file mode 100644
index 0000000..e6b37e3
--- /dev/null
+++ b/app/lib/db-init.server.ts
@@ -0,0 +1,73 @@
+import { execSync } from "node:child_process";
+import prisma from "./prisma.server";
+
+let initStarted = false;
+let initCompleted = false;
+
+/**
+ * Run Prisma migrations to bring database schema up to date
+ */
+async function runMigrations(): Promise<void> {
+  try {
+    console.log("[DB Init] Running Prisma migrations...");
+    execSync("npx prisma migrate deploy", {
+      stdio: "inherit",
+      env: { ...process.env },
+    });
+    console.log("[DB Init] ✓ Migrations completed successfully");
+  } catch (error) {
+    console.error("[DB Init] ✗ Migration failed:", error);
+    throw new Error("Database migration failed. See logs above.");
+  }
+}
+
+/**
+ * Initialize database: run all pending migrations
+ * Safe to call multiple times (idempotent)
+ */
+export async function initializeDatabase(): Promise<void> {
+  // Prevent concurrent initialization attempts
+  if (initCompleted) return;
+  if (initStarted) {
+    // Wait for initialization to complete
+    while (!initCompleted) {
+      await new Promise((resolve) => setTimeout(resolve, 100));
+    }
+    return;
+  }
+
+  initStarted = true;
+
+  try {
+    await runMigrations();
+    console.log("[DB Init] ✓ Database initialization complete");
+  } catch (error) {
+    console.error("[DB Init] Fatal error during database initialization:", error);
+    throw error;
+  } finally {
+    initCompleted = true;
+  }
+}
+
+/**
+ * Check database health (non-blocking)
+ */
+export async function checkDatabaseHealth(): Promise<{
+  connected: boolean;
+  isEmpty: boolean;
+  error?: string;
+}> {
+  try {
+    const userCount = await prisma.user.count();
+    return {
+      connected: true,
+      isEmpty: userCount === 0,
+    };
+  } catch (error) {
+    return {
+      connected: false,
+      isEmpty: false,
+      error: error instanceof Error ? error.message : "Unknown error",
+    };
+  }
+}
diff --git a/app/lib/error-logger.server.ts b/app/lib/error-logger.server.ts
new file mode 100644
index 0000000..7976623
--- /dev/null
+++ b/app/lib/error-logger.server.ts
@@ -0,0 +1,227 @@
+/**
+ * Comprehensive server-side error logging for debugging
+ * Captures errors with full context: stack traces, request details, environment
+ */
+
+export interface ErrorContext {
+  request?: Request;
+  userId?: string | null;
+  route?: string;
+  metadata?: Record<string, unknown>;
+}
+
+export interface ErrorLogEntry {
+  timestamp: string;
+  type: string;
+  message: string;
+  stack?: string;
+  context?: {
+    method?: string;
+    url?: string;
+    route?: string;
+    userId?: string | null;
+    ipAddress?: string | null;
+    userAgent?: string;
+    metadata?: Record<string, unknown>;
+  };
+  environment: string;
+}
+
+/**
+ * Extract error message and stack from any error type
+ */
+function extractErrorInfo(error: unknown): { message: string; stack?: string } {
+  if (error instanceof Error) {
+    return {
+      message: error.message,
+      stack: error.stack,
+    };
+  }
+
+  if (typeof error === "string") {
+    return { message: error };
+  }
+
+  if (error && typeof error === "object") {
+    const err = error as Record<string, unknown>;
+    return {
+      message: (err.message as string) || String(error),
+      stack: (err.stack as string) || undefined,
+    };
+  }
+
+  return { message: String(error) };
+}
+
+/**
+ * Extract request context
+ */
+function extractRequestContext(
+  request?: Request
+): ErrorLogEntry["context"] {
+  if (!request) return {};
+
+  const url = new URL(request.url);
+  const ipAddress =
+    request.headers.get("x-forwarded-for") ??
+    request.headers.get("x-real-ip") ??
+    null;
+  const userAgent = request.headers.get("user-agent");
+
+  return {
+    method: request.method,
+    url: url.pathname + url.search,
+    ipAddress,
+    userAgent: userAgent ?? undefined,
+  };
+}
+
+/**
+ * Build comprehensive error log entry
+ */
+function buildErrorLogEntry(
+  type: string,
+  error: unknown,
+  context?: ErrorContext
+): ErrorLogEntry {
+  const { message, stack } = extractErrorInfo(error);
+  const requestContext = extractRequestContext(context?.request);
+
+  return {
+    timestamp: new Date().toISOString(),
+    type,
+    message,
+    stack,
+    context: {
+      ...requestContext,
+      route: context?.route,
+      userId: context?.userId,
+      metadata: context?.metadata,
+    },
+    environment: process.env.NODE_ENV || "development",
+  };
+}
+
+/**
+ * Format error log for console output
+ */
+function formatErrorLog(entry: ErrorLogEntry): string {
+  const parts = [
+    `[${entry.type}]`,
+    `${entry.timestamp}`,
+    entry.message,
+  ];
+
+  if (entry.context?.route) parts.push(`route: ${entry.context.route}`);
+  if (entry.context?.method && entry.context?.url) {
+    parts.push(`${entry.context.method} ${entry.context.url}`);
+  }
+  if (entry.context?.userId) parts.push(`user: ${entry.context.userId}`);
+  if (entry.context?.ipAddress) parts.push(`ip: ${entry.context.ipAddress}`);
+
+  let output = parts.join(" | ");
+
+  if (entry.stack) {
+    output += "\n" + entry.stack;
+  }
+
+  if (entry.context?.metadata) {
+    output += "\nMetadata: " + JSON.stringify(entry.context.metadata, null, 2);
+  }
+
+  return output;
+}
+
+/**
+ * Log a route/loader error
+ */
+export function logRouteError(
+  error: unknown,
+  context: ErrorContext & { route: string }
+): void {
+  const entry = buildErrorLogEntry("ROUTE_ERROR", error, context);
+  console.error("\n" + "=".repeat(80));
+  console.error(formatErrorLog(entry));
+  console.error("=".repeat(80) + "\n");
+}
+
+/**
+ * Log an action/mutation error
+ */
+export function logActionError(
+  error: unknown,
+  context: ErrorContext & { action: string }
+): void {
+  const entry = buildErrorLogEntry("ACTION_ERROR", error, {
+    ...context,
+    metadata: {
+      action: context.action,
+      ...context.metadata,
+    },
+  });
+  console.error("\n" + "=".repeat(80));
+  console.error(formatErrorLog(entry));
+  console.error("=".repeat(80) + "\n");
+}
+
+/**
+ * Log a database error
+ */
+export function logDatabaseError(
+  error: unknown,
+  operation: string,
+  context?: Omit<ErrorContext, "metadata">
+): void {
+  const entry = buildErrorLogEntry("DATABASE_ERROR", error, {
+    ...context,
+    metadata: { operation },
+  });
+  console.error("\n" + "=".repeat(80));
+  console.error(formatErrorLog(entry));
+  console.error("=".repeat(80) + "\n");
+}
+
+/**
+ * Log an API error
+ */
+export function logApiError(
+  error: unknown,
+  context: ErrorContext & { endpoint: string; statusCode?: number }
+): void {
+  const entry = buildErrorLogEntry("API_ERROR", error, {
+    ...context,
+    metadata: {
+      endpoint: context.endpoint,
+      statusCode: context.statusCode || 500,
+      ...context.metadata,
+    },
+  });
+  console.error("\n" + "=".repeat(80));
+  console.error(formatErrorLog(entry));
+  console.error("=".repeat(80) + "\n");
+}
+
+/**
+ * Log a server startup error
+ */
+export function logStartupError(error: unknown): void {
+  const entry = buildErrorLogEntry("STARTUP_ERROR", error);
+  console.error("\n" + "=".repeat(80));
+  console.error("🚨 CRITICAL: Server failed to start");
+  console.error(formatErrorLog(entry));
+  console.error("=".repeat(80) + "\n");
+}
+
+/**
+ * Log a generic error with type
+ */
+export function logError(
+  type: string,
+  error: unknown,
+  context?: ErrorContext
+): void {
+  const entry = buildErrorLogEntry(type, error, context);
+  console.error("\n" + "=".repeat(80));
+  console.error(formatErrorLog(entry));
+  console.error("=".repeat(80) + "\n");
+}
diff --git a/app/lib/logger.server.ts b/app/lib/logger.server.ts
index 60bcd51..4790156 100644
--- a/app/lib/logger.server.ts
+++ b/app/lib/logger.server.ts
@@ -47,9 +47,21 @@ export async function log({
     : undefined;
 
   try {
+    // Validate that userId exists in the database if provided
+    let validatedUserId = userId;
+    if (userId) {
+      const userExists = await prisma.user.findUnique({
+        where: { id: userId },
+        select: { id: true },
+      });
+      if (!userExists) {
+        validatedUserId = null; // User doesn't exist, log as anonymous
+      }
+    }
+
     await prisma.auditLog.create({
       data: {
-        userId: userId ?? null,
+        userId: validatedUserId ?? null,
         action,
         entity: entity ?? null,
         entityId: entityId ?? null,
diff --git a/app/lib/schemas.ts b/app/lib/schemas.ts
index 993a1bf..d7f97ed 100644
--- a/app/lib/schemas.ts
+++ b/app/lib/schemas.ts
@@ -35,7 +35,7 @@ export const taxRateSchema = z
 export const ibanSchema = z
   .string()
   .refine(
-    (iban) => /^[A-Z]{2}\d{2}[A-Z0-9]{1,30}$/.test(iban),
+    (iban) => iban === "" || /^[A-Z]{2}\d{2}[A-Z0-9]{1,30}$/.test(iban),
     "Ungültige IBAN"
   );
 
@@ -44,14 +44,20 @@ export const ibanSchema = z
  */
 export const taxIdSchema = z
   .string()
-  .regex(/^\d{10}$/, "Steuernummer muss 10 Ziffern haben");
+  .refine(
+    (val) => val === "" || /^\d{10}$/.test(val),
+    "Steuernummer muss 10 Ziffern haben"
+  );
 
 /**
  * VAT ID (Umsatzsteuer-IdNr): DE + 9 digits
  */
 export const vatIdSchema = z
   .string()
-  .regex(/^DE\d{9}$/, "USt-IdNr. muss im Format DE + 9 Ziffern sein");
+  .refine(
+    (val) => val === "" || /^DE\d{9}$/.test(val),
+    "USt-IdNr. muss im Format DE + 9 Ziffern sein"
+  );
 
 // ===== Invoice Schemas =====
 
@@ -131,8 +137,8 @@ export const companySchema = z.object({
     .string()
     .max(100, "Rechtsform darf maximal 100 Zeichen sein")
     .optional(),
-  taxId: taxIdSchema.optional(),
-  vatId: vatIdSchema.optional(),
+  taxId: taxIdSchema.nullable(),
+  vatId: vatIdSchema.nullable(),
   address: z
     .string()
     .min(1, "Adresse erforderlich")
@@ -162,14 +168,22 @@ export const companySchema = z.object({
     .optional(),
   website: z
     .string()
-    .url("Ungültige URL")
+    .refine(
+      (val) => val === "" || /^https?:\/\//.test(val),
+      "Website muss mit http:// oder https:// beginnen"
+    )
     .max(255, "Website darf maximal 255 Zeichen sein")
-    .optional(),
-  bankIban: ibanSchema.optional(),
+    .optional()
+    .or(z.literal("")),
+  bankIban: ibanSchema.nullable(),
   bankBic: z
     .string()
-    .regex(/^[A-Z0-9]{8,11}$/, "Ungültiger BIC")
-    .optional(),
+    .refine(
+      (val) => val === "" || /^[A-Z0-9]{8,11}$/.test(val),
+      "Ungültiger BIC"
+    )
+    .optional()
+    .or(z.literal("")),
   bankName: z
     .string()
     .max(255, "Bankname darf maximal 255 Zeichen sein")
diff --git a/app/root.tsx b/app/root.tsx
index cab0814..5688e11 100644
--- a/app/root.tsx
+++ b/app/root.tsx
@@ -1,21 +1,61 @@
 import { Links, Meta, Outlet, Scripts, ScrollRestoration, isRouteErrorResponse, useRouteError } from "react-router";
 import "./app.css";
+import { DebugPanel } from "./components/debug-panel";
 
 export function ErrorBoundary() {
   const error = useRouteError();
-  const message = isRouteErrorResponse(error)
+  
+  // Get error details
+  const isResponse = isRouteErrorResponse(error);
+  const status = isResponse ? error.status : 500;
+  const statusText = isResponse ? error.statusText : "Internal Server Error";
+  const message = isResponse
     ? `${error.status} ${error.statusText}`
     : error instanceof Error
     ? error.message
     : String(error);
   const stack = error instanceof Error ? error.stack : undefined;
+
+  // Log error details for debugging
+  if (typeof console !== "undefined") {
+    console.error("\n" + "=".repeat(80));
+    console.error("[ERROR_BOUNDARY]", new Date().toISOString());
+    console.error(`Status: ${status} ${statusText}`);
+    console.error(`Message: ${message}`);
+    if (stack) console.error("Stack:\n" + stack);
+    if (error && typeof error === "object") {
+      console.error("Full Error Object:", error);
+    }
+    console.error("=".repeat(80) + "\n");
+  }
+
   return (
     <html lang="de">
-      <head><meta charSet="utf-8" /><Meta /><Links /></head>
+      <head>
+        <meta charSet="utf-8" />
+        <Meta />
+        <Links />
+      </head>
       <body style={{ fontFamily: "monospace", padding: "2rem", background: "#fff1f2", color: "#9f1239" }}>
-        <h1 style={{ fontSize: "1.5rem", fontWeight: 700, marginBottom: "1rem" }}>Fehler</h1>
-        <pre style={{ whiteSpace: "pre-wrap", wordBreak: "break-word", background: "#ffe4e6", padding: "1rem", borderRadius: "0.5rem" }}>{message}</pre>
-        {import.meta.env.DEV && stack && <pre style={{ marginTop: "1rem", fontSize: "0.75rem", color: "#64748b", whiteSpace: "pre-wrap" }}>{stack}</pre>}
+        <h1 style={{ fontSize: "1.5rem", fontWeight: 700, marginBottom: "1rem" }}>
+          {status} Fehler
+        </h1>
+        <p style={{ marginBottom: "1rem", fontSize: "0.9rem" }}>
+          {statusText}
+        </p>
+        <pre style={{ whiteSpace: "pre-wrap", wordBreak: "break-word", background: "#ffe4e6", padding: "1rem", borderRadius: "0.5rem" }}>
+          {message}
+        </pre>
+        {import.meta.env.DEV && stack && (
+          <details style={{ marginTop: "1rem" }}>
+            <summary style={{ cursor: "pointer", fontWeight: 600, color: "#64748b" }}>
+              Stack Trace (Dev Only)
+            </summary>
+            <pre style={{ marginTop: "0.5rem", fontSize: "0.75rem", color: "#64748b", whiteSpace: "pre-wrap", background: "#f1f5f9", padding: "1rem", borderRadius: "0.5rem" }}>
+              {stack}
+            </pre>
+          </details>
+        )}
         <Scripts />
       </body>
     </html>
@@ -45,5 +85,10 @@ export function Layout({ children }: { children: React.ReactNode }) {
 }
 
 export default function App() {
-  return <Outlet />;
+  return (
+    <>
+      <Outlet />
+      <DebugPanel />
+    </>
+  );
 }
diff --git a/app/routes.ts b/app/routes.ts
index 05fb5ad..ad4a1f6 100644
--- a/app/routes.ts
+++ b/app/routes.ts
@@ -45,6 +45,7 @@ export default [
   route("api/companies/:id/customers", "routes/api.companies.$id.customers.ts"),
   route("api/companies/:id/invoices", "routes/api.companies.$id.invoices.ts"),
   route("api/companies/:id/money", "routes/api.companies.$id.money.ts"),
+  route("api/admin/companies/:id/delete", "routes/api.admin.companies.$id.delete.ts"),
   route("api/customers", "routes/api.customers.ts"),
   route("api/customers/:id", "routes/api.customers.$id.ts"),
   route("api/services", "routes/api.services.ts"),
diff --git a/app/routes/admin.mandanten.tsx b/app/routes/admin.mandanten.tsx
index 57e985c..f53db2f 100644
--- a/app/routes/admin.mandanten.tsx
+++ b/app/routes/admin.mandanten.tsx
@@ -2,7 +2,8 @@ import { Link, useLoaderData } from "react-router";
 import { requireAdmin } from "@/session.server";
 import prisma from "@/lib/prisma.server";
 import { Badge } from "@/components/ui/badge";
-import { Building2, Archive } from "lucide-react";
+import { Building2, Archive, Trash2 } from "lucide-react";
+import { useState } from "react";
 
 export async function loader({ request }: { request: Request }) {
   await requireAdmin(request);
@@ -68,6 +69,37 @@ function MandantenTabelle({
   title: string;
   archived?: boolean;
 }) {
+  const [deleteConfirm, setDeleteConfirm] = useState<string | null>(null);
+  const [isDeleting, setIsDeleting] = useState(false);
+
+  const handleDelete = async (companyId: string, companyName: string) => {
+    if (deleteConfirm !== companyId) {
+      setDeleteConfirm(companyId);
+      return;
+    }
+
+    setIsDeleting(true);
+    try {
+      const response = await fetch(`/api/admin/companies/${companyId}/delete`, {
+        method: "DELETE",
+      });
+
+      if (response.ok) {
+        // Reload the page to refresh the list
+        window.location.reload();
+      } else {
+        const error = await response.json();
+        alert(`Fehler beim Löschen: ${error.error || response.statusText}`);
+        setDeleteConfirm(null);
+      }
+    } catch (error) {
+      alert(`Fehler beim Löschen: ${error}`);
+      setDeleteConfirm(null);
+    } finally {
+      setIsDeleting(false);
+    }
+  };
+
   if (companies.length === 0) return null;
 
   return (
@@ -113,13 +145,25 @@ function MandantenTabelle({
                 </td>
                 <td className="px-4 py-3 text-right text-slate-600">{company._count.invoices}</td>
                 <td className="px-4 py-3 text-right text-slate-600">{company._count.customers}</td>
-                <td className="px-4 py-3 text-right">
+                <td className="px-4 py-3 text-right space-x-2 flex justify-end">
                   <Link
                     to={`/companies/${company.id}`}
                     className="text-indigo-600 hover:text-indigo-800 font-medium text-xs"
                   >
                     Öffnen →
                   </Link>
+                  <button
+                    onClick={() => handleDelete(company.id, company.name)}
+                    disabled={isDeleting}
+                    className={`text-xs font-medium flex items-center gap-1 px-2 py-1 rounded transition-colors ${
+                      deleteConfirm === company.id
+                        ? "bg-red-100 text-red-700 hover:bg-red-200"
+                        : "text-slate-500 hover:text-red-600"
+                    } ${isDeleting ? "opacity-50 cursor-not-allowed" : ""}`}
+                  >
+                    <Trash2 className="w-3.5 h-3.5" />
+                    {deleteConfirm === company.id ? "Bestätigen?" : "Löschen"}
+                  </button>
                 </td>
               </tr>
             ))}
diff --git a/app/routes/api.admin.companies.$id.delete.ts b/app/routes/api.admin.companies.$id.delete.ts
new file mode 100644
index 0000000..5cf3dd9
--- /dev/null
+++ b/app/routes/api.admin.companies.$id.delete.ts
@@ -0,0 +1,34 @@
+import { requireAdmin } from "@/session.server";
+import prisma from "@/lib/prisma.server";
+import { log } from "@/lib/logger.server";
+
+export async function action({ request, params }: { request: Request; params: { id: string } }) {
+  const user = await requireAdmin(request);
+
+  if (request.method !== "DELETE") {
+    return Response.json({ error: "Method not allowed" }, { status: 405 });
+  }
+
+  const company = await prisma.company.findUnique({
+    where: { id: params.id },
+  });
+
+  if (!company) {
+    return Response.json({ error: "Company not found" }, { status: 404 });
+  }
+
+  await prisma.company.delete({
+    where: { id: params.id },
+  });
+
+  await log({
+    userId: user.id,
+    action: "DELETE_COMPANY",
+    entity: "Company",
+    entityId: params.id,
+    metadata: { companyName: company.name },
+    request,
+  });
+
+  return Response.json({ ok: true });
+}
diff --git a/app/routes/api.companies.ts b/app/routes/api.companies.ts
index 3037b76..504dabf 100644
--- a/app/routes/api.companies.ts
+++ b/app/routes/api.companies.ts
@@ -1,36 +1,56 @@
 import { getApiUser } from "@/session.server";
 import prisma from "@/lib/prisma.server";
 import { log } from "@/lib/logger.server";
+import { logApiError } from "@/lib/error-logger.server";
 import { companySchema } from "@/lib/schemas";
 
 export async function loader({ request }: { request: Request }) {
-  const user = await getApiUser(request);
-  if (!user) return Response.json({ error: "Unauthorized" }, { status: 401 });
+  try {
+    const user = await getApiUser(request);
+    if (!user) return Response.json({ error: "Unauthorized" }, { status: 401 });
 
-  const companies = await prisma.company.findMany({
-    where: { userId: user.id },
-    include: { _count: { select: { invoices: true, customers: true } } },
-    orderBy: { name: "asc" },
-  });
+    const companies = await prisma.company.findMany({
+      where: { userId: user.id },
+      include: { _count: { select: { invoices: true, customers: true } } },
+      orderBy: { name: "asc" },
+    });
 
-  return Response.json(companies);
+    return Response.json(companies);
+  } catch (error) {
+    logApiError(error, {
+      request,
+      endpoint: "/api/companies",
+      statusCode: 500,
+    });
+    return Response.json({ error: "Internal server error" }, { status: 500 });
+  }
 }
 
 export async function action({ request }: { request: Request }) {
-  const user = await getApiUser(request);
-  if (!user) return Response.json({ error: "Unauthorized" }, { status: 401 });
+  try {
+    const user = await getApiUser(request);
+    if (!user) return Response.json({ error: "Unauthorized" }, { status: 401 });
 
-  const body = await request.json();
-  const parsed = companySchema.safeParse(body);
-  if (!parsed.success) {
-    return Response.json({ error: parsed.error.issues }, { status: 400 });
+    const body = await request.json();
+    const parsed = companySchema.safeParse(body);
+    if (!parsed.success) {
+      console.warn("[CompanyAPI] Validation failed:", parsed.error.issues);
+      return Response.json({ error: parsed.error.issues }, { status: 400 });
+    }
+
+    const company = await prisma.company.create({
+      data: { ...parsed.data, userId: user.id },
+    });
+
+    await log({ userId: user.id, action: "CREATE_COMPANY", entity: "Company", entityId: company.id, request });
+
+    return Response.json(company, { status: 201 });
+  } catch (error) {
+    logApiError(error, {
+      request,
+      endpoint: "/api/companies",
+      statusCode: 500,
+    });
+    return Response.json({ error: "Internal server error" }, { status: 500 });
   }
-
-  const company = await prisma.company.create({
-    data: { ...parsed.data, userId: user.id },
-  });
-
-  await log({ userId: user.id, action: "CREATE_COMPANY", entity: "Company", entityId: company.id, request });
-
-  return Response.json(company, { status: 201 });
 }
diff --git a/app/routes/api.invoices.$id.ts b/app/routes/api.invoices.$id.ts
index e119409..f9846b5 100644
--- a/app/routes/api.invoices.$id.ts
+++ b/app/routes/api.invoices.$id.ts
@@ -5,6 +5,8 @@ import { calcItemAmounts, calcInvoiceTotals, calcItemAmountsKleinunternehmer } f
 import { log } from "@/lib/logger.server";
 import { InvoiceStatus } from "@prisma/client";
 import { invoiceUpdateSchema, invoiceStatusSchema, invoiceItemSchema } from "@/lib/schemas";
+import { writeFile, mkdir } from "node:fs/promises";
+import { join, resolve } from "node:path";
 
 async function getInvoice(id: string, userId: string) {
   return prisma.invoice.findFirst({
@@ -13,6 +15,39 @@ async function getInvoice(id: string, userId: string) {
   });
 }
 
+/** Storage root for documents */
+function storageRoot(): string {
+  return resolve(process.env.BELEG_STORAGE_PATH ?? "data/documents");
+}
+
+/** Generate and save invoice PDF as beleg (receipt) */
+async function generateAndSaveInvoicePDF(invoice: Awaited<ReturnType<typeof getInvoice>>, userId: string): Promise<string | null> {
+  if (!invoice) return null;
+
+  try {
+    const { renderToBuffer } = await import("@react-pdf/renderer");
+    const React = (await import("react")).default;
+    const { InvoicePDFDocument } = await import("@/components/invoice/invoice-pdf");
+
+    // eslint-disable-next-line @typescript-eslint/no-explicit-any
+    const element = React.createElement(InvoicePDFDocument as any, { invoice }) as any;
+    const buffer = await renderToBuffer(element);
+
+    // Save to storage
+    const safeName = `${invoice.id}-${Date.now()}.pdf`;
+    const userDir = join(storageRoot(), userId);
+    await mkdir(userDir, { recursive: true });
+    await writeFile(join(userDir, safeName), Buffer.from(buffer));
+
+    // Return as "beleg:{userId}/{storedName}|{originalName}"
+    const originalName = `rechnung-${invoice.number ?? invoice.id}.pdf`;
+    return `beleg:${userId}/${safeName}|${originalName}`;
+  } catch {
+    console.error("Failed to generate invoice PDF");
+    return null;
+  }
+}
+
 export async function loader({ request, params }: { request: Request; params: { id: string } }) {
   const user = await getApiUser(request);
   if (!user) return Response.json({ error: "Unauthorized" }, { status: 401 });
@@ -148,6 +183,16 @@ export async function action({ request, params }: { request: Request; params: {
 
   // Handle Buchung sync: Create when PAID, delete when unpaying
   if (newStatus === "PAID" && oldStatus !== "PAID") {
+    // Generate and save invoice PDF as beleg
+    const belegUrl = await generateAndSaveInvoicePDF(invoice, user.id);
+
+    // Calculate weighted average tax rate (kann mehrere Items mit unterschiedlichen Steuersätzen geben)
+    let averageTaxRate = 0;
+    if (invoice.taxTotal > 0 && invoice.netTotal > 0) {
+      // steuersatz = (taxTotal / netTotal) * 100
+      averageTaxRate = Math.round((invoice.taxTotal / invoice.netTotal) * 100);
+    }
+
     // Create a Buchung for the invoice payment
     const buchung = await prisma.buchung.create({
       data: {
@@ -159,6 +204,8 @@ export async function action({ request, params }: { request: Request; params: {
         description: `Rechnung ${invoice.number}`,
         kategorie: "Rechnungseinnahme",
         isBusinessRecord: true,
+        steuersatz: invoice.kleinunternehmer ? 0 : averageTaxRate, // 0 for Kleinunternehmer
+        belegUrl: belegUrl, // Attach the generated invoice PDF
       },
     });
 
@@ -179,7 +226,7 @@ export async function action({ request, params }: { request: Request; params: {
       action: "UPDATE_INVOICE_STATUS",
       entity: "Invoice",
       entityId: params.id,
-      metadata: { oldStatus, newStatus, buchungId: buchung.id },
+      metadata: { oldStatus, newStatus, buchungId: buchung.id, belegUrl, steuersatz: averageTaxRate },
       request,
     });
 
diff --git a/app/routes/companies.new.tsx b/app/routes/companies.new.tsx
index e679ea7..2792640 100644
--- a/app/routes/companies.new.tsx
+++ b/app/routes/companies.new.tsx
@@ -1,3 +1,4 @@
+
 import { Link, useNavigate } from "react-router";
 
 export const handle = {
diff --git a/app/routes/companies.tsx b/app/routes/companies.tsx
index 69d1c47..fb7ce04 100644
--- a/app/routes/companies.tsx
+++ b/app/routes/companies.tsx
@@ -230,6 +230,12 @@ export default function CompaniesPage() {
 
             {/* Aktionen */}
             <div className="flex gap-2 p-4 border-b border-slate-100">
+              <Button variant="outline" size="sm" asChild className="flex-1">
+                <Link to={`/companies/${selected.id}`}>
+                  <ChevronRight className="h-3.5 w-3.5" />
+                  Dashboard
+                </Link>
+              </Button>
               <Button variant="outline" size="sm" asChild className="flex-1">
                 <Link to={`/companies/${selected.id}/edit`}>
                   <Edit className="h-3.5 w-3.5" />
diff --git a/docker-compose.yml b/docker-compose.yml
index 9ad19c6..7551108 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -21,7 +21,7 @@ services:
 
   app:
   # registry.henryathome.home64.de/henry/annasrechnungsmanager:latest
-    image: annasrechnungsmanager:latest
+    image: git.henryathome.home64.de/henry/annasrechnungsmanager:latest
     container_name: annas_app
     restart: unless-stopped
     ports:
diff --git a/package-lock.json b/package-lock.json
index 2899e68..2bc6605 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -17,6 +17,7 @@
         "@radix-ui/react-separator": "^1.1.8",
         "@radix-ui/react-slot": "^1.2.4",
         "@radix-ui/react-toast": "^1.2.15",
+        "@radix-ui/react-tooltip": "^1.2.8",
         "@react-pdf/renderer": "^4.3.2",
         "@react-router/node": "^7.13.1",
         "@react-router/serve": "^7",
@@ -2075,6 +2076,58 @@
         }
       }
     },
+    "node_modules/@radix-ui/react-tooltip": {
+      "version": "1.2.8",
+      "resolved": "https://registry.npmjs.org/@radix-ui/react-tooltip/-/react-tooltip-1.2.8.tgz",
+      "integrity": "sha512-tY7sVt1yL9ozIxvmbtN5qtmH2krXcBCfjEiCgKGLqunJHvgvZG2Pcl2oQ3kbcZARb1BGEHdkLzcYGO8ynVlieg==",
+      "license": "MIT",
+      "dependencies": {
+        "@radix-ui/primitive": "1.1.3",
+        "@radix-ui/react-compose-refs": "1.1.2",
+        "@radix-ui/react-context": "1.1.2",
+        "@radix-ui/react-dismissable-layer": "1.1.11",
+        "@radix-ui/react-id": "1.1.1",
+        "@radix-ui/react-popper": "1.2.8",
+        "@radix-ui/react-portal": "1.1.9",
+        "@radix-ui/react-presence": "1.1.5",
+        "@radix-ui/react-primitive": "2.1.3",
+        "@radix-ui/react-slot": "1.2.3",
+        "@radix-ui/react-use-controllable-state": "1.2.2",
+        "@radix-ui/react-visually-hidden": "1.2.3"
+      },
+      "peerDependencies": {
+        "@types/react": "*",
+        "@types/react-dom": "*",
+        "react": "^16.8 || ^17.0 || ^18.0 || ^19.0 || ^19.0.0-rc",
+        "react-dom": "^16.8 || ^17.0 || ^18.0 || ^19.0 || ^19.0.0-rc"
+      },
+      "peerDependenciesMeta": {
+        "@types/react": {
+          "optional": true
+        },
+        "@types/react-dom": {
+          "optional": true
+        }
+      }
+    },
+    "node_modules/@radix-ui/react-tooltip/node_modules/@radix-ui/react-slot": {
+      "version": "1.2.3",
+      "resolved": "https://registry.npmjs.org/@radix-ui/react-slot/-/react-slot-1.2.3.tgz",
+      "integrity": "sha512-aeNmHnBxbi2St0au6VBVC7JXFlhLlOnvIIlePNniyUNAClzmtAUEY8/pBiK3iHjufOlwA+c20/8jngo7xcrg8A==",
+      "license": "MIT",
+      "dependencies": {
+        "@radix-ui/react-compose-refs": "1.1.2"
+      },
+      "peerDependencies": {
+        "@types/react": "*",
+        "react": "^16.8 || ^17.0 || ^18.0 || ^19.0 || ^19.0.0-rc"
+      },
+      "peerDependenciesMeta": {
+        "@types/react": {
+          "optional": true
+        }
+      }
+    },
     "node_modules/@radix-ui/react-use-callback-ref": {
       "version": "1.1.1",
       "resolved": "https://registry.npmjs.org/@radix-ui/react-use-callback-ref/-/react-use-callback-ref-1.1.1.tgz",
diff --git a/package.json b/package.json
index 87ddee8..e6879ef 100644
--- a/package.json
+++ b/package.json
@@ -29,6 +29,7 @@
     "@radix-ui/react-separator": "^1.1.8",
     "@radix-ui/react-slot": "^1.2.4",
     "@radix-ui/react-toast": "^1.2.15",
+    "@radix-ui/react-tooltip": "^1.2.8",
     "@react-pdf/renderer": "^4.3.2",
     "@react-router/node": "^7.13.1",
     "@react-router/serve": "^7",
diff --git a/prisma/migrations/20260502_add_belegurl/migration.sql b/prisma/migrations/20260502_add_belegurl/migration.sql
new file mode 100644
index 0000000..e5de6c4
--- /dev/null
+++ b/prisma/migrations/20260502_add_belegurl/migration.sql
@@ -0,0 +1 @@
+ALTER TABLE `buchungen` ADD COLUMN `belegUrl` LONGTEXT;