i18n: migrate from German-first to English-first default locale

Switch defaultLocale from "de" to "en" and make English the code-level
language throughout. All ~145 hardcoded German strings translated:

- API error messages (52 routes) now return English
- Zod validation messages in English
- Classification/analytics functions return English categories
- Notification type labels in English
- Component strings use i18n t() calls (heatmap, mood chart,
  medication form, intake history, password strength, insights card)
- ~50 new i18n keys in both de.json and en.json

Route migration:
- /stimmung → /mood, /zielwerte → /targets (new pages)
- 301 redirects in proxy.ts for legacy URLs
- Sidebar + bottom nav updated

Bump version to 1.0.1.

src/app/api/admin/data/route.ts

@@ -30,11 +30,11 @@ export const DELETE = apiHandler(async (request: NextRequest) => {
     const body = await request.json();
     confirm = typeof body?.confirm === "string" ? body.confirm : "";
   } catch {
-    return apiError("Ungültige Anfrage", 422);
+    return apiError("Invalid request", 422);
   }
 
   if (confirm !== "DELETE ALL") {
-    return apiError("Bestätigung fehlt", 422);
+    return apiError("Confirmation missing", 422);
   }
 
   const result = await prisma.$transaction(async (tx) => {

src/app/api/admin/monitoring/glitchtip-test/route.ts

@@ -12,10 +12,10 @@ export const POST = apiHandler(async () => {
 
   const settings = await getGlitchtipSettings();
   if (!settings.glitchtipEnabled) {
-    return apiError("Glitchtip ist deaktiviert", 422);
+    return apiError("Glitchtip is disabled", 422);
   }
   if (!settings.glitchtipDsn) {
-    return apiError("Glitchtip DSN fehlt", 422);
+    return apiError("Glitchtip DSN is missing", 422);
   }
 
   const delivery = await sendGlitchtipEvent({
@@ -32,13 +32,13 @@ export const POST = apiHandler(async () => {
   if (!delivery.ok) {
     getEvent()?.addWarning("Glitchtip test event rejected: " + delivery.method + " " + delivery.status + " " + delivery.details);
     return apiError(
-      `Glitchtip-Testevent wurde abgelehnt (HTTP ${delivery.status ?? 502})`,
+      `Glitchtip test event rejected (HTTP ${delivery.status ?? 502})`,
       502,
     );
   }
 
   return apiSuccess({
     sent: true,
-    message: "Glitchtip-Testevent wurde gesendet",
+    message: "Glitchtip test event sent",
   });
 });

src/app/api/admin/monitoring/umami-test/route.ts

@@ -51,18 +51,18 @@ export const POST = apiHandler(async (request: NextRequest) => {
 
   const settings = await getPublicMonitoringSettings();
   if (!settings.umamiEnabled) {
-    return apiError("Umami ist deaktiviert", 422);
+    return apiError("Umami is disabled", 422);
   }
   if (!settings.umamiScriptUrl || !settings.umamiWebsiteId) {
     return apiError(
-      "Umami Script-URL und Website-ID müssen konfiguriert sein",
+      "Umami script URL and website ID must be configured",
       422,
     );
   }
 
   const targetUrls = resolveUmamiSendUrls(settings.umamiScriptUrl);
   if (targetUrls.length === 0) {
-    return apiError("Umami Script-URL ist ungültig", 422);
+    return apiError("Umami script URL is invalid", 422);
   }
 
   const appUrl = resolveAppUrl(request);
@@ -100,7 +100,7 @@ export const POST = apiHandler(async (request: NextRequest) => {
     if (upstream.ok) {
       return apiSuccess({
         sent: true,
-        message: "Umami-Testevent wurde gesendet",
+        message: "Umami test event sent",
       });
     }
 
@@ -117,7 +117,7 @@ export const POST = apiHandler(async (request: NextRequest) => {
 
   getEvent()?.addWarning("Umami test event rejected: " + lastStatus);
   return apiError(
-    `Umami-Testevent wurde abgelehnt (HTTP ${lastStatus})`,
+    `Umami test event rejected (HTTP ${lastStatus})`,
     502,
   );
 });

src/app/api/admin/notifications/test/route.ts

@@ -79,7 +79,7 @@ export const POST = apiHandler(async () => {
   if (channels.length === 0) {
     return apiSuccess({
       sent: false,
-      message: "Keine aktivierten Benachrichtigungskanäle gefunden",
+      message: "No enabled notification channels found",
       results: [],
     });
   }
@@ -89,7 +89,7 @@ export const POST = apiHandler(async () => {
     userId: user.id,
     title: "Test-Notification",
     message:
-      "<b>HealthLog Test:</b> Wenn du diese Nachricht siehst, funktionieren deine Benachrichtigungen!",
+      "<b>HealthLog Test:</b> If you see this message, your notifications are working!",
   };
 
   const results: Array<{
@@ -104,7 +104,7 @@ export const POST = apiHandler(async () => {
       results.push({
         channel: channel.type,
         success: false,
-        error: "SYSTEM_ALERT deaktiviert in Einstellungen",
+        error: "SYSTEM_ALERT disabled in settings",
       });
       continue;
     }
@@ -124,7 +124,7 @@ export const POST = apiHandler(async () => {
             results.push({
               channel: "TELEGRAM",
               success: false,
-              error: `Telegram API hat Fehler gemeldet (chatId: ${config.chatId})`,
+              error: `Telegram API reported error (chatId: ${config.chatId})`,
             });
             continue;
           }
@@ -139,7 +139,7 @@ export const POST = apiHandler(async () => {
             results.push({
               channel: "NTFY",
               success: false,
-              error: `Senden fehlgeschlagen (topic: ${config.topic})`,
+              error: `Send failed (topic: ${config.topic})`,
             });
             continue;
           }
@@ -153,7 +153,7 @@ export const POST = apiHandler(async () => {
           results.push({
             channel: type,
             success: false,
-            error: "Unbekannter Kanaltyp",
+            error: "Unknown channel type",
           });
           continue;
       }
@@ -163,7 +163,7 @@ export const POST = apiHandler(async () => {
       results.push({
         channel: channel.type,
         success: false,
-        error: err instanceof Error ? err.message : "Unbekannter Fehler",
+        error: err instanceof Error ? err.message : "Unknown error",
       });
     }
   }
@@ -173,11 +173,11 @@ export const POST = apiHandler(async () => {
 
   let message: string;
   if (failCount === 0) {
-    message = `Alle ${successCount} Kanäle erfolgreich`;
+    message = `All ${successCount} channels successful`;
   } else if (successCount === 0) {
-    message = `Alle ${failCount} Kanäle fehlgeschlagen`;
+    message = `All ${failCount} channels failed`;
   } else {
-    message = `${successCount} erfolgreich, ${failCount} fehlgeschlagen`;
+    message = `${successCount} successful, ${failCount} failed`;
   }
 
   return apiSuccess({ sent: successCount > 0, message, results });

src/app/api/admin/settings/route.ts

@@ -180,7 +180,7 @@ export const PUT = apiHandler(async (request: NextRequest) => {
   }
 
   if (Object.keys(updates).length === 0) {
-    return apiError("Keine gültigen Felder", 422);
+    return apiError("No valid fields", 422);
   }
 
   const settings = await prisma.appSettings.upsert({

src/app/api/admin/users/[id]/reset-password/route.ts

@@ -32,16 +32,16 @@ export const POST = apiHandler(async (
   const { password } = body as { password?: string };
 
   if (!password || typeof password !== "string") {
-    return apiError("Passwort erforderlich", 422);
+    return apiError("Password required", 422);
   }
 
   const target = await prisma.user.findUnique({ where: { id } });
-  if (!target) return apiError("Benutzer nicht gefunden", 404);
+  if (!target) return apiError("User not found", 404);
 
   const strength = checkPasswordStrength(password, [target.username]);
   if (!strength.isAcceptable) {
     return apiError(
-      strength.feedback[0] || "Passwort zu schwach (Score < 3)",
+      strength.feedback[0] || "Password too weak (score < 3)",
       422,
     );
   }

src/app/api/admin/users/[id]/route.ts

@@ -30,13 +30,13 @@ export const PUT = apiHandler(async (
   }
 
   const target = await prisma.user.findUnique({ where: { id } });
-  if (!target) return apiError("Benutzer nicht gefunden", 404);
+  if (!target) return apiError("User not found", 404);
 
   // Prevent removing the last admin
   if (parsed.data.role === "USER" && target.role === "ADMIN") {
     const adminCount = await prisma.user.count({ where: { role: "ADMIN" } });
     if (adminCount <= 1) {
-      return apiError("Der letzte Admin kann nicht degradiert werden", 400);
+      return apiError("The last admin cannot be demoted", 400);
     }
   }
 

src/app/api/auth/login/route.ts

@@ -17,7 +17,7 @@ export const POST = apiHandler(async (request: NextRequest) => {
     return NextResponse.json(
       {
         data: null,
-        error: "Zu viele Anmeldeversuche. Bitte später erneut versuchen.",
+        error: "Too many login attempts. Please try again later.",
       },
       { status: 429, headers: rateLimitHeaders(rl) },
     );
@@ -31,7 +31,7 @@ export const POST = apiHandler(async (request: NextRequest) => {
   const parsed = loginPasswordSchema.safeParse(body);
 
   if (!parsed.success) {
-    return apiError("Ungültige Anmeldedaten", 422);
+    return apiError("Invalid credentials", 422);
   }
 
   const { email, password } = parsed.data;
@@ -51,7 +51,7 @@ export const POST = apiHandler(async (request: NextRequest) => {
       ipAddress: ip,
       details: { identifier, reason: "user_not_found_or_no_password" },
     });
-    return apiError("Ungültige Anmeldedaten", 401);
+    return apiError("Invalid credentials", 401);
   }
 
   const valid = await verifyPassword(user.passwordHash, password);
@@ -61,7 +61,7 @@ export const POST = apiHandler(async (request: NextRequest) => {
       ipAddress: ip,
       details: { reason: "invalid_password" },
     });
-    return apiError("Ungültige Anmeldedaten", 401);
+    return apiError("Invalid credentials", 401);
   }
 
   const ua = request.headers.get("user-agent");

src/app/api/auth/passkey/login-options/route.ts

@@ -16,7 +16,7 @@ export const POST = apiHandler(async (request: Request) => {
     return NextResponse.json(
       {
         data: null,
-        error: "Zu viele Passkey-Anfragen. Bitte später erneut versuchen.",
+        error: "Too many passkey requests. Please try again later.",
       },
       { status: 429, headers: rateLimitHeaders(rl) },
     );

src/app/api/auth/passkey/login-verify/route.ts

@@ -15,7 +15,7 @@ export const POST = apiHandler(async (request: NextRequest) => {
   const ip = getClientIp(request);
   const rl = await checkRateLimit(`auth:passkey-verify:${ip}`, 10, 15 * 60 * 1000);
   if (!rl.allowed) {
-    return apiError("Zu viele Versuche. Bitte 15 Minuten warten.", 429);
+    return apiError("Too many attempts. Please wait 15 minutes.", 429);
   }
 
   const { data: body, error: jsonError } = await safeJson<Record<string, unknown>>(request);
@@ -25,7 +25,7 @@ export const POST = apiHandler(async (request: NextRequest) => {
   const credential = body.credential;
 
   if (!challengeId || !credential) {
-    return apiError("challengeId und credential erforderlich", 422);
+    return apiError("challengeId and credential required", 422);
   }
 
   const { verification, passkey } = await verifyAuthentication(
@@ -38,7 +38,7 @@ export const POST = apiHandler(async (request: NextRequest) => {
       ipAddress: ip,
       details: { reason: "passkey_verification_failed" },
     });
-    return apiError("Passkey-Verifizierung fehlgeschlagen", 401);
+    return apiError("Passkey verification failed", 401);
   }
 
   const user = await prisma.user.findUnique({
@@ -46,7 +46,7 @@ export const POST = apiHandler(async (request: NextRequest) => {
   });
 
   if (!user) {
-    return apiError("Benutzer nicht gefunden", 404);
+    return apiError("User not found", 404);
   }
 
   const ua = request.headers.get("user-agent");

src/app/api/auth/passkey/register-verify/route.ts

@@ -16,13 +16,13 @@ export const POST = apiHandler(async (request: NextRequest) => {
   const credential = body.credential as Record<string, unknown> | undefined;
 
   if (!challengeId || !credential) {
-    return apiError("challengeId und credential erforderlich", 422);
+    return apiError("challengeId and credential required", 422);
   }
 
   const verification = await verifyRegistration(challengeId, credential);
 
   if (!verification.verified || !verification.registrationInfo) {
-    return apiError("Passkey-Verifizierung fehlgeschlagen", 400);
+    return apiError("Passkey verification failed", 400);
   }
 
   const { registrationInfo } = verification;

src/app/api/auth/passkeys/[id]/route.ts

@@ -18,7 +18,7 @@ export const DELETE = apiHandler(async (
   });
 
   if (!passkey || passkey.userId !== user.id) {
-    return apiError("Passkey nicht gefunden", 404);
+    return apiError("Passkey not found", 404);
   }
 
   // Check: at least 1 auth method must remain
@@ -29,7 +29,7 @@ export const DELETE = apiHandler(async (
 
   if (passkeyCount <= 1 && !hasPassword) {
     return apiError(
-      "Kann nicht gelöscht werden — es muss mindestens eine Anmeldemethode bestehen bleiben",
+      "Cannot delete — at least one authentication method must remain",
       400,
     );
   }

src/app/api/auth/password/route.ts

@@ -23,7 +23,7 @@ export const POST = apiHandler(async (request: NextRequest) => {
   );
   if (!rl.allowed) {
     return apiError(
-      "Zu viele Versuche. Bitte 15 Minuten warten.",
+      "Too many attempts. Please wait 15 minutes.",
       429,
     );
   }
@@ -38,7 +38,7 @@ export const POST = apiHandler(async (request: NextRequest) => {
 
   const { currentPassword, newPassword } = parsed.data;
   if (!user.passwordHash) {
-    return apiError("Für dieses Konto ist kein Passwort gesetzt", 400);
+    return apiError("No password set for this account", 400);
   }
 
   const currentValid = await verifyPassword(
@@ -46,12 +46,12 @@ export const POST = apiHandler(async (request: NextRequest) => {
     currentPassword,
   );
   if (!currentValid) {
-    return apiError("Aktuelles Passwort ist falsch", 401);
+    return apiError("Current password is incorrect", 401);
   }
 
   if (currentPassword === newPassword) {
     return apiError(
-      "Neues Passwort muss sich vom aktuellen unterscheiden",
+      "New password must differ from current password",
       422,
     );
   }
@@ -62,7 +62,7 @@ export const POST = apiHandler(async (request: NextRequest) => {
   ]);
   if (!strength.isAcceptable) {
     return apiError(
-      strength.feedback[0] || "Passwort zu schwach (Score < 3)",
+      strength.feedback[0] || "Password too weak (score < 3)",
       422,
     );
   }

src/app/api/auth/profile/route.ts

@@ -28,7 +28,7 @@ export const PUT = apiHandler(async (request: NextRequest) => {
     });
 
     if (existingUser && existingUser.id !== user.id) {
-      return apiError("E-Mail-Adresse wird bereits verwendet", 409);
+      return apiError("Email already in use", 409);
     }
   }
 

src/app/api/auth/register/route.ts

@@ -18,7 +18,7 @@ export const POST = apiHandler(async (request: NextRequest) => {
       {
         data: null,
         error:
-          "Zu viele Registrierungsversuche. Bitte später erneut versuchen.",
+          "Too many registration attempts. Please try again later.",
       },
       { status: 429, headers: rateLimitHeaders(rl) },
     );
@@ -42,7 +42,7 @@ export const POST = apiHandler(async (request: NextRequest) => {
     // Table may not exist yet; allow registration
   }
   if (!registrationEnabled) {
-    return apiError("Registrierung ist deaktiviert", 403);
+    return apiError("Registration is disabled", 403);
   }
 
   const { data: body, error: jsonError } = await safeJson(request);
@@ -62,14 +62,14 @@ export const POST = apiHandler(async (request: NextRequest) => {
     prisma.user.findUnique({ where: { username } }),
   ]);
   if (existingEmail || existingUsername) {
-    return apiError("Benutzername oder E-Mail-Adresse bereits vergeben", 409);
+    return apiError("Username or email already taken", 409);
   }
 
   // Validate password strength
   const strength = checkPasswordStrength(password, [username, email]);
   if (!strength.isAcceptable) {
     return apiError(
-      strength.feedback[0] || "Passwort zu schwach (Score < 3)",
+      strength.feedback[0] || "Password too weak (score < 3)",
       422,
     );
   }

src/app/api/bugreport/route.ts

@@ -9,10 +9,10 @@ import { NextRequest } from "next/server";
 import { z } from "zod/v4";
 
 const bugReportSchema = z.object({
-  description: z.string().min(10, "Beschreibung zu kurz").max(5000),
+  description: z.string().min(10, "Description too short").max(5000),
   screenshot: z
     .string()
-    .max(7_000_000, "Screenshot zu groß (max. 5 MB)")
+    .max(7_000_000, "Screenshot too large (max 5 MB)")
     .optional(),
 });
 
@@ -21,7 +21,7 @@ export const POST = apiHandler(async (request: NextRequest) => {
 
   const rl = await checkRateLimit(`bugreport:${user.id}`, 3, 60 * 60 * 1000);
   if (!rl.allowed) {
-    return apiError("Maximal 3 Bugreports pro Stunde", 429);
+    return apiError("Maximum 3 bug reports per hour", 429);
   }
 
   annotate({ action: { name: "bugreport.submit" } });
@@ -48,7 +48,7 @@ export const POST = apiHandler(async (request: NextRequest) => {
 
   if (!ghToken || !ghRepo) {
     return apiError(
-      "Bugreport ist nicht konfiguriert (GitHub-Issue-Token/Repository in Admin-Einstellungen fehlt)",
+      "Bug report not configured (GitHub issue token/repository missing in admin settings)",
       500,
     );
   }
@@ -75,15 +75,15 @@ export const POST = apiHandler(async (request: NextRequest) => {
     .slice(0, 5000);
 
   // Build issue body
-  let issueBody = `**Gemeldet von:** ${safeUsername}\n`;
-  issueBody += `**Datum:** ${dateStr}\n\n`;
-  issueBody += `## Beschreibung\n\n${safeDescription}\n`;
-  issueBody += `\n---\n*Erstellt über die HealthLog Bugreport-Funktion*`;
+  let issueBody = `**Reported by:** ${safeUsername}\n`;
+  issueBody += `**Date:** ${dateStr}\n\n`;
+  issueBody += `## Description\n\n${safeDescription}\n`;
+  issueBody += `\n---\n*Created via HealthLog bug report*`;
 
   // If screenshot provided, upload to GitHub as a gist or include as base64
   // For simplicity, we'll note there's a screenshot but GitHub issues don't support inline base64
   if (screenshot) {
-    issueBody += `\n\n**Screenshot:** Ein Screenshot wurde angehängt (siehe Kommentar).`;
+    issueBody += `\n\n**Screenshot:** A screenshot was attached (see comment).`;
   }
 
   // Create the issue
@@ -107,7 +107,7 @@ export const POST = apiHandler(async (request: NextRequest) => {
   if (!issueRes.ok) {
     const errBody = await issueRes.text();
     getEvent()?.addWarning("GitHub issue creation failed: " + errBody);
-    return apiError("Issue konnte nicht erstellt werden", 500);
+    return apiError("Failed to create issue", 500);
   }
 
   const issue = (await issueRes.json()) as {
@@ -123,7 +123,7 @@ export const POST = apiHandler(async (request: NextRequest) => {
 
     // Upload screenshot as issue comment with embedded image
     // GitHub doesn't support base64 in comments, so we note the limitation
-    const commentBody = `### Screenshot\n\n![Screenshot](data:image/${ext};base64,${base64Data.slice(0, 100)}...)\n\n*Hinweis: Der vollständige Screenshot wurde aus Größengründen gekürzt. Bitte den Nutzer direkt kontaktieren.*`;
+    const commentBody = `### Screenshot\n\n![Screenshot](data:image/${ext};base64,${base64Data.slice(0, 100)}...)\n\n*Note: The full screenshot was truncated due to size limits. Please contact the user directly.*`;
 
     await fetch(
       `https://api.github.com/repos/${ghRepo}/issues/${issue.number}/comments`,

src/app/api/doctor-report/route.ts

@@ -16,7 +16,7 @@ export const POST = apiHandler(async (request: NextRequest) => {
 
   const rl = await checkRateLimit(`doctor-report:${user.id}`, 10, 60 * 60 * 1000);
   if (!rl.allowed) {
-    return apiError("Maximal 10 Reports pro Stunde", 429);
+    return apiError("Maximum 10 reports per hour", 429);
   }
 
   const { data: body, error: jsonError } = await safeJson(request);

src/app/api/export/route.ts

@@ -26,7 +26,7 @@ export const GET = apiHandler(async (request: NextRequest) => {
 
   const rl = await checkRateLimit(`export:${user.id}`, 10, 60 * 60 * 1000);
   if (!rl.allowed) {
-    return apiError("Maximal 10 Exports pro Stunde", 429);
+    return apiError("Maximum 10 exports per hour", 429);
   }
 
   annotate({ action: { name: "export.download" } });
@@ -36,10 +36,10 @@ export const GET = apiHandler(async (request: NextRequest) => {
   const type = searchParams.get("type") ?? "all";
 
   if (!["csv", "json"].includes(format)) {
-    return apiError("Format muss csv oder json sein", 422);
+    return apiError("Format must be csv or json", 422);
   }
   if (!["measurements", "medications", "intake", "mood", "all"].includes(type)) {
-    return apiError("Typ muss measurements, medications, intake, mood oder all sein", 422);
+    return apiError("Type must be measurements, medications, intake, mood, or all", 422);
   }
 
   const userId = user.id;

src/app/api/ingest/medication/route.ts

@@ -19,7 +19,7 @@ export const POST = apiHandler(async (request: NextRequest) => {
   annotate({ action: { name: "ingest.medication" } });
 
   if (!(await isApiGloballyEnabled())) {
-    return apiError("API ist global deaktiviert", 403);
+    return apiError("API is globally disabled", 403);
   }
 
   const ip = getClientIp(request);
@@ -109,12 +109,12 @@ export const POST = apiHandler(async (request: NextRequest) => {
   });
 
   if (!medication) {
-    return apiError("Medikament nicht gefunden", 404);
+    return apiError("Medication not found", 404);
   }
 
   const medicationScope = `medication:${medication.id}:ingest`;
   if (!apiToken.permissions.includes(medicationScope)) {
-    return apiError("API-Endpoint fuer dieses Medikament ist deaktiviert", 403);
+    return apiError("API endpoint for this medication is disabled", 403);
   }
 
   const event = await prisma.medicationIntakeEvent.create({

src/app/api/insights/generate/route.ts

@@ -27,7 +27,7 @@ export const POST = apiHandler(async (request: NextRequest) => {
   const rl = await checkRateLimit(`insights:${userId}`, 2, 60 * 60 * 1000);
   if (!rl.allowed) {
     return apiError(
-      "Maximal 2 Insights-Generierungen pro Stunde. Bitte spaeter erneut versuchen.",
+      "Maximum 2 insight generations per hour. Please try again later.",
       429,
     );
   }
@@ -44,7 +44,7 @@ export const POST = apiHandler(async (request: NextRequest) => {
 
   if (!dbUser?.openaiKeyEncrypted) {
     return apiError(
-      "Kein OpenAI API-Key hinterlegt. Bitte in den Einstellungen konfigurieren.",
+      "No OpenAI API key configured. Please set it in settings.",
       422,
     );
   }
@@ -105,23 +105,23 @@ export const POST = apiHandler(async (request: NextRequest) => {
     const errBody = await openaiRes.text();
     annotate({ meta: { openai_status: openaiRes.status, openai_error: errBody } });
     if (openaiRes.status === 401) {
-      return apiError("Ungueltiger OpenAI API-Key", 422);
+      return apiError("Invalid OpenAI API key", 422);
     }
-    return apiError("OpenAI-Anfrage fehlgeschlagen", 502);
+    return apiError("OpenAI request failed", 502);
   }
 
   const openaiJson = await openaiRes.json();
   const content = openaiJson.choices?.[0]?.message?.content;
 
   if (!content) {
-    return apiError("Keine Antwort von OpenAI erhalten", 502);
+    return apiError("No response from OpenAI", 502);
   }
 
   let insights: InsightsOutput;
   try {
     insights = JSON.parse(content);
   } catch {
-    return apiError("OpenAI-Antwort konnte nicht verarbeitet werden", 502);
+    return apiError("Failed to parse OpenAI response", 502);
   }
 
   // Cache the result

src/app/api/insights/settings/route.ts

@@ -51,7 +51,7 @@ export const PUT = apiHandler(async (request: NextRequest) => {
     } else {
       if (!key.startsWith("sk-")) {
         return apiError(
-          "Ungueltiges API-Key-Format (muss mit sk- beginnen)",
+          "Invalid API key format (must start with sk-)",
           422,
         );
       }
@@ -63,7 +63,7 @@ export const PUT = apiHandler(async (request: NextRequest) => {
   if (typeof body.privacyMode === "string") {
     const mode = body.privacyMode as string;
     if (!["aggregated", "raw"].includes(mode)) {
-      return apiError("Ungueltiger Privacy-Modus", 422);
+      return apiError("Invalid privacy mode", 422);
     }
     data.insightsPrivacyMode = mode;
     // Clear cache when privacy mode changes
@@ -72,7 +72,7 @@ export const PUT = apiHandler(async (request: NextRequest) => {
   }
 
   if (Object.keys(data).length === 0) {
-    return apiError("Keine Aenderungen", 422);
+    return apiError("No changes", 422);
   }
 
   await prisma.user.update({

src/app/api/insights/targets/route.ts

@@ -161,7 +161,7 @@ export const GET = apiHandler(async () => {
   }
   targets.push({
     type: "WEIGHT",
-    label: "Gewicht",
+    label: "Weight",
     current: latestByType.WEIGHT ?? null,
     average30: avg30ByType.WEIGHT ?? null,
     trend: computeTrend("WEIGHT"),
@@ -186,7 +186,7 @@ export const GET = apiHandler(async () => {
   }
   targets.push({
     type: "BLOOD_PRESSURE",
-    label: "Blutdruck",
+    label: "Blood pressure",
     current: latestByType.BLOOD_PRESSURE_SYS ?? null,
     average30: avg30ByType.BLOOD_PRESSURE_SYS ?? null,
     trend: computeTrend("BLOOD_PRESSURE_SYS"),
@@ -227,7 +227,7 @@ export const GET = apiHandler(async () => {
 
     targets.push({
       type: "BLOOD_PRESSURE_IN_TARGET",
-      label: "Blutdruck im Zielbereich",
+      label: "Blood pressure on target",
       current: bpInTargetRate,
       average30: bpInTargetRate,
       trend: null,
@@ -236,10 +236,10 @@ export const GET = apiHandler(async () => {
       classification:
         bpInTargetRate != null
           ? bpInTargetRate >= 70
-            ? { category: "Gut", color: "#50fa7b" }
+            ? { category: "Good", color: "#50fa7b" }
             : bpInTargetRate >= 40
-              ? { category: "Moderat", color: "#f1fa8c" }
-              : { category: "Niedrig", color: "#ff5555" }
+              ? { category: "Moderate", color: "#f1fa8c" }
+              : { category: "Low", color: "#ff5555" }
           : null,
       source: "ESC/ESH 2018",
     });
@@ -254,7 +254,7 @@ export const GET = apiHandler(async () => {
   }
   targets.push({
     type: "PULSE",
-    label: "Ruhepuls",
+    label: "Resting pulse",
     current: latestByType.PULSE ?? null,
     average30: avg30ByType.PULSE ?? null,
     trend: computeTrend("PULSE"),
@@ -273,7 +273,7 @@ export const GET = apiHandler(async () => {
   }
   targets.push({
     type: "SLEEP_DURATION",
-    label: "Schlafdauer",
+    label: "Sleep duration",
     current: latestByType.SLEEP_DURATION ?? null,
     average30: avg30ByType.SLEEP_DURATION ?? null,
     trend: computeTrend("SLEEP_DURATION"),
@@ -335,7 +335,7 @@ export const GET = apiHandler(async () => {
   }
   targets.push({
     type: "BODY_FAT",
-    label: "Koerperfett",
+    label: "Body fat",
     current: latestByType.BODY_FAT ?? null,
     average30: avg30ByType.BODY_FAT ?? null,
     trend: computeTrend("BODY_FAT"),
@@ -354,11 +354,11 @@ export const GET = apiHandler(async () => {
   }
   targets.push({
     type: "ACTIVITY_STEPS",
-    label: "Schritte/Tag",
+    label: "Steps/day",
     current: latestByType.ACTIVITY_STEPS ?? null,
     average30: avg30ByType.ACTIVITY_STEPS ?? null,
     trend: computeTrend("ACTIVITY_STEPS"),
-    unit: "Schritte",
+    unit: "steps",
     range: stepsRange,
     classification: stepsClassification,
     source: "WHO",
@@ -453,7 +453,7 @@ export const GET = apiHandler(async () => {
 
     targets.push({
       type: "MEDICATION_COMPLIANCE",
-      label: "Einnahmetreue",
+      label: "Medication compliance",
       current: complianceRate7,
       average30: complianceRate30,
       trend: null,
@@ -462,12 +462,12 @@ export const GET = apiHandler(async () => {
       classification:
         complianceRate7 != null
           ? complianceRate7 >= 90
-            ? { category: "Sehr gut", color: "#50fa7b" }
+            ? { category: "Very good", color: "#50fa7b" }
             : complianceRate7 >= 70
-              ? { category: "Gut", color: "#f1fa8c" }
-              : { category: "Niedrig", color: "#ff5555" }
+              ? { category: "Good", color: "#f1fa8c" }
+              : { category: "Low", color: "#ff5555" }
           : null,
-      source: "7-Tage",
+      source: "7-day",
       details: {
         medications: medicationStats.map((medication) => ({
           name: medication.name,
@@ -523,15 +523,15 @@ export const GET = apiHandler(async () => {
     const moodClassification =
       latestMoodScore != null
         ? latestMoodScore >= 3.5
-          ? { category: "Gut", color: "#50fa7b" }
+          ? { category: "Good", color: "#50fa7b" }
           : latestMoodScore >= 2
-            ? { category: "Moderat", color: "#f1fa8c" }
-            : { category: "Niedrig", color: "#ff5555" }
+            ? { category: "Moderate", color: "#f1fa8c" }
+            : { category: "Low", color: "#ff5555" }
         : null;
 
     targets.push({
       type: "MOOD_SCORE",
-      label: "Stimmung",
+      label: "Mood",
       current: latestMoodScore,
       average30: moodAvg30,
       trend: moodTrend,
@@ -551,14 +551,14 @@ export const GET = apiHandler(async () => {
 
       const stabilityClassification =
         stdDev <= 0.5
-          ? { category: "Sehr stabil", color: "#50fa7b" }
+          ? { category: "Very stable", color: "#50fa7b" }
           : stdDev <= 1.0
-            ? { category: "Stabil", color: "#f1fa8c" }
-            : { category: "Schwankend", color: "#ff5555" };
+            ? { category: "Stable", color: "#f1fa8c" }
+            : { category: "Fluctuating", color: "#ff5555" };
 
       targets.push({
         type: "MOOD_STABILITY",
-        label: "Stimmungsstabilitaet",
+        label: "Mood stability",
         current: stdDev,
         average30: stdDev,
         trend: null,

src/app/api/integrations/moodlog/sync/route.ts

@@ -17,7 +17,7 @@ export const POST = apiHandler(async (request: NextRequest) => {
     select: { moodLogGlobal: true },
   });
   if (appSettings && !appSettings.moodLogGlobal) {
-    return apiError("moodLog-Integration ist deaktiviert", 403);
+    return apiError("moodLog integration is disabled", 403);
   }
 
   let fullSync = false;

src/app/api/measurements/[id]/route.ts

@@ -18,7 +18,7 @@ export const GET = apiHandler(async (_request: NextRequest, { params }: RoutePar
   });
 
   if (!measurement || measurement.userId !== user.id) {
-    return apiError("Messwert nicht gefunden", 404);
+    return apiError("Measurement not found", 404);
   }
 
   annotate({
@@ -42,7 +42,7 @@ export const PUT = apiHandler(async (request: NextRequest, { params }: RoutePara
   });
 
   if (!existing || existing.userId !== user.id) {
-    return apiError("Messwert nicht gefunden", 404);
+    return apiError("Measurement not found", 404);
   }
 
   const { data: body, error: jsonError } = await safeJson(request);
@@ -90,7 +90,7 @@ export const DELETE = apiHandler(async (request: NextRequest, { params }: RouteP
   });
 
   if (!existing || existing.userId !== user.id) {
-    return apiError("Messwert nicht gefunden", 404);
+    return apiError("Measurement not found", 404);
   }
 
   await prisma.measurement.delete({ where: { id } });

src/app/api/measurements/route.ts

@@ -134,7 +134,7 @@ export const POST = apiHandler(async (request: NextRequest) => {
     });
   } catch (err) {
     if (err instanceof Prisma.PrismaClientKnownRequestError && err.code === "P2002") {
-      return apiError("Ein Messwert mit diesen Daten existiert bereits", 409);
+      return apiError("A measurement with this data already exists", 409);
     }
     throw err;
   }

src/app/api/medications/[id]/api-endpoint/route.ts

@@ -17,13 +17,13 @@ function medicationScope(medicationId: string): string {
 export const GET = apiHandler(async (_request: NextRequest, { params }: RouteParams) => {
   const { user } = await requireAuth();
   if (!(await isApiGloballyEnabled())) {
-    return apiError("API ist global deaktiviert", 403);
+    return apiError("API is globally disabled", 403);
   }
 
   const { id } = await params;
   const medication = await prisma.medication.findUnique({ where: { id } });
   if (!medication || medication.userId !== user.id) {
-    return apiError("Medikament nicht gefunden", 404);
+    return apiError("Medication not found", 404);
   }
 
   const scope = medicationScope(id);
@@ -56,13 +56,13 @@ export const GET = apiHandler(async (_request: NextRequest, { params }: RoutePar
 export const PUT = apiHandler(async (request: NextRequest, { params }: RouteParams) => {
   const { user } = await requireAuth();
   if (!(await isApiGloballyEnabled())) {
-    return apiError("API ist global deaktiviert", 403);
+    return apiError("API is globally disabled", 403);
   }
 
   const { id } = await params;
   const medication = await prisma.medication.findUnique({ where: { id } });
   if (!medication || medication.userId !== user.id) {
-    return apiError("Medikament nicht gefunden", 404);
+    return apiError("Medication not found", 404);
   }
 
   let enabled = false;
@@ -70,7 +70,7 @@ export const PUT = apiHandler(async (request: NextRequest, { params }: RoutePara
     const body = await request.json();
     enabled = body?.enabled === true;
   } catch {
-    return apiError("Ungültige Anfrage", 422);
+    return apiError("Invalid request", 422);
   }
 
   const scope = medicationScope(id);

src/app/api/medications/[id]/compliance/route.ts

@@ -20,7 +20,7 @@ export const GET = apiHandler(async (_request: Request, { params }: RouteParams)
   });
 
   if (!medication || medication.userId !== user.id) {
-    return apiError("Medikament nicht gefunden", 404);
+    return apiError("Medication not found", 404);
   }
 
   const events = await prisma.medicationIntakeEvent.findMany({

src/app/api/medications/[id]/intake/[eventId]/route.ts

@@ -22,7 +22,7 @@ export const PUT = apiHandler(async (request: NextRequest, { params }: RoutePara
     event.userId !== user.id ||
     event.medicationId !== id
   ) {
-    return apiError("Einnahme nicht gefunden", 404);
+    return apiError("Intake not found", 404);
   }
 
   const { data: body, error: jsonError } = await safeJson(request);
@@ -77,7 +77,7 @@ export const DELETE = apiHandler(async (request: NextRequest, { params }: RouteP
     event.userId !== user.id ||
     event.medicationId !== id
   ) {
-    return apiError("Einnahme nicht gefunden", 404);
+    return apiError("Intake not found", 404);
   }
 
   await prisma.medicationIntakeEvent.delete({ where: { id: eventId } });

src/app/api/medications/[id]/intake/import/route.ts

@@ -22,7 +22,7 @@ export const POST = apiHandler(async (request: NextRequest, { params }: RoutePar
   const { id } = await params;
   const medication = await prisma.medication.findUnique({ where: { id } });
   if (!medication || medication.userId !== user.id) {
-    return apiError("Medikament nicht gefunden", 404);
+    return apiError("Medication not found", 404);
   }
 
   const { data: body, error: jsonError } = await safeJson(request);
@@ -39,7 +39,7 @@ export const POST = apiHandler(async (request: NextRequest, { params }: RoutePar
   const parsed = importSchema.safeParse(payload);
   if (!parsed.success) {
     return apiError(
-      `Ungültiges Format: ${parsed.error.issues[0].message}`,
+      `Invalid format: ${parsed.error.issues[0].message}`,
       422,
     );
   }

src/app/api/medications/[id]/intake/purge/route.ts

@@ -13,7 +13,7 @@ export const DELETE = apiHandler(async (request: NextRequest, { params }: RouteP
   const { id } = await params;
   const medication = await prisma.medication.findUnique({ where: { id } });
   if (!medication || medication.userId !== user.id) {
-    return apiError("Medikament nicht gefunden", 404);
+    return apiError("Medication not found", 404);
   }
 
   const { count } = await prisma.medicationIntakeEvent.deleteMany({

src/app/api/medications/[id]/intake/route.ts

@@ -17,7 +17,7 @@ export const POST = apiHandler(async (request: NextRequest, { params }: RoutePar
   const { id } = await params;
   const medication = await prisma.medication.findUnique({ where: { id } });
   if (!medication || medication.userId !== user.id) {
-    return apiError("Medikament nicht gefunden", 404);
+    return apiError("Medication not found", 404);
   }
 
   const { data: body, error: jsonError } = await safeJson(request);
@@ -108,7 +108,7 @@ export const GET = apiHandler(async (request: NextRequest, { params }: RoutePara
   const { id } = await params;
   const medication = await prisma.medication.findUnique({ where: { id } });
   if (!medication || medication.userId !== user.id) {
-    return apiError("Medikament nicht gefunden", 404);
+    return apiError("Medication not found", 404);
   }
 
   const searchParams = Object.fromEntries(request.nextUrl.searchParams);

src/app/api/medications/[id]/phase-config/route.ts

@@ -16,7 +16,7 @@ export const GET = apiHandler(async (_request: NextRequest, { params }: RoutePar
     select: { userId: true },
   });
   if (!medication || medication.userId !== user.id) {
-    return apiError("Medikament nicht gefunden", 404);
+    return apiError("Medication not found", 404);
   }
 
   const config = await prisma.reminderPhaseConfig.findUnique({
@@ -55,7 +55,7 @@ export const PUT = apiHandler(async (request: NextRequest, { params }: RoutePara
     select: { userId: true },
   });
   if (!medication || medication.userId !== user.id) {
-    return apiError("Medikament nicht gefunden", 404);
+    return apiError("Medication not found", 404);
   }
 
   const { data: body, error: jsonError } = await safeJson(request);
@@ -63,7 +63,7 @@ export const PUT = apiHandler(async (request: NextRequest, { params }: RoutePara
   if (jsonError) return jsonError;
   const parsed = phaseConfigSchema.safeParse(body);
   if (!parsed.success) {
-    return apiError("Ungültige Eingabe", 400);
+    return apiError("Invalid input", 400);
   }
 
   const config = await prisma.reminderPhaseConfig.upsert({
@@ -95,7 +95,7 @@ export const DELETE = apiHandler(async (_request: NextRequest, { params }: Route
     select: { userId: true },
   });
   if (!medication || medication.userId !== user.id) {
-    return apiError("Medikament nicht gefunden", 404);
+    return apiError("Medication not found", 404);
   }
 
   await prisma.reminderPhaseConfig.deleteMany({

src/app/api/medications/[id]/route.ts

@@ -24,7 +24,7 @@ export const GET = apiHandler(async (_request: NextRequest, { params }: RoutePar
   });
 
   if (!medication || medication.userId !== user.id) {
-    return apiError("Medikament nicht gefunden", 404);
+    return apiError("Medication not found", 404);
   }
 
   let category = "OTHER";
@@ -52,7 +52,7 @@ export const PUT = apiHandler(async (request: NextRequest, { params }: RoutePara
   const { id } = await params;
   const existing = await prisma.medication.findUnique({ where: { id } });
   if (!existing || existing.userId !== user.id) {
-    return apiError("Medikament nicht gefunden", 404);
+    return apiError("Medication not found", 404);
   }
 
   const { data: body, error: jsonError } = await safeJson(request);
@@ -171,7 +171,7 @@ export const DELETE = apiHandler(async (request: NextRequest, { params }: RouteP
   const { id } = await params;
   const existing = await prisma.medication.findUnique({ where: { id } });
   if (!existing || existing.userId !== user.id) {
-    return apiError("Medikament nicht gefunden", 404);
+    return apiError("Medication not found", 404);
   }
 
   // Revoke API tokens scoped to this medication

src/app/api/monitoring/glitchtip/route.ts

@@ -32,11 +32,11 @@ export const POST = apiHandler(async (request: NextRequest) => {
   try {
     body = await request.json();
   } catch {
-    return apiError("Ungültige JSON-Daten", 422);
+    return apiError("Invalid JSON data", 422);
   }
 
   const parsed = clientErrorSchema.safeParse(body);
-  if (!parsed.success) return apiError("Ungültige Fehlerdaten", 422);
+  if (!parsed.success) return apiError("Invalid error data", 422);
 
   const delivery = await sendGlitchtipEvent({
     dsn: settings.glitchtipDsn,
@@ -54,7 +54,7 @@ export const POST = apiHandler(async (request: NextRequest) => {
 
   if (!delivery.ok) {
     getEvent()?.addWarning("Glitchtip event rejected: " + delivery.method + " " + delivery.status + " " + delivery.details);
-    return apiError("Glitchtip konnte Fehler nicht annehmen", 502);
+    return apiError("Glitchtip could not accept error", 502);
   }
 
   return apiSuccess({ sent: true });

src/app/api/mood-entries/[id]/route.ts

@@ -34,7 +34,7 @@ export const GET = apiHandler(async (_request: NextRequest, { params }: RoutePar
   const entry = await prisma.moodEntry.findUnique({ where: { id } });
 
   if (!entry || entry.userId !== user.id) {
-    return apiError("Stimmungseintrag nicht gefunden", 404);
+    return apiError("Mood entry not found", 404);
   }
 
   annotate({ action: { name: "mood-entries.get" }, meta: { moodEntryId: id } });
@@ -50,7 +50,7 @@ export const PUT = apiHandler(async (request: NextRequest, { params }: RoutePara
   const existing = await prisma.moodEntry.findUnique({ where: { id } });
 
   if (!existing || existing.userId !== user.id) {
-    return apiError("Stimmungseintrag nicht gefunden", 404);
+    return apiError("Mood entry not found", 404);
   }
 
   const { data: body, error: jsonError } = await safeJson(request);
@@ -100,7 +100,7 @@ export const DELETE = apiHandler(async (request: NextRequest, { params }: RouteP
   const existing = await prisma.moodEntry.findUnique({ where: { id } });
 
   if (!existing || existing.userId !== user.id) {
-    return apiError("Stimmungseintrag nicht gefunden", 404);
+    return apiError("Mood entry not found", 404);
   }
 
   await prisma.moodEntry.delete({ where: { id } });

src/app/api/mood-entries/route.ts

@@ -113,7 +113,7 @@ export const POST = apiHandler(async (request: NextRequest) => {
   } catch (err) {
     if (err instanceof Prisma.PrismaClientKnownRequestError && err.code === "P2002") {
       return apiError(
-        "Ein Stimmungseintrag mit diesen Daten existiert bereits",
+        "A mood entry with this data already exists",
         409,
       );
     }

src/app/api/notifications/preferences/route.ts

@@ -98,18 +98,18 @@ export const PUT = apiHandler(async (request: NextRequest) => {
   try {
     body = await request.json();
   } catch {
-    return apiError("Ungültige JSON-Daten", 422);
+    return apiError("Invalid JSON data", 422);
   }
 
   const parsed = notificationPreferenceSchema.safeParse(body);
-  if (!parsed.success) return apiError("Ungültige Daten", 422);
+  if (!parsed.success) return apiError("Invalid data", 422);
 
   const { channelId, eventType, enabled } = parsed.data;
 
   const channel = await prisma.notificationChannel.findFirst({
     where: { id: channelId, userId: user.id },
   });
-  if (!channel) return apiError("Kanal nicht gefunden", 404);
+  if (!channel) return apiError("Channel not found", 404);
 
   const preference = await prisma.notificationPreference.upsert({
     where: {

src/app/api/notifications/web-push/route.ts

@@ -30,11 +30,11 @@ export const POST = apiHandler(async (request: NextRequest) => {
   try {
     body = await request.json();
   } catch {
-    return apiError("Ungültige JSON-Daten", 422);
+    return apiError("Invalid JSON data", 422);
   }
 
   const parsed = subscribeSchema.safeParse(body);
-  if (!parsed.success) return apiError("Ungültige Daten", 422);
+  if (!parsed.success) return apiError("Invalid data", 422);
 
   const { endpoint, keys } = parsed.data;
   const userAgent = request.headers.get("user-agent") ?? undefined;
@@ -92,11 +92,11 @@ export const DELETE = apiHandler(async (request: NextRequest) => {
   try {
     body = await request.json();
   } catch {
-    return apiError("Ungültige JSON-Daten", 422);
+    return apiError("Invalid JSON data", 422);
   }
 
   const parsed = unsubscribeSchema.safeParse(body);
-  if (!parsed.success) return apiError("Ungültige Daten", 422);
+  if (!parsed.success) return apiError("Invalid data", 422);
 
   await prisma.pushSubscription.deleteMany({
     where: {

src/app/api/onboarding/complete/route.ts

@@ -24,7 +24,7 @@ export const POST = apiHandler(async (request: NextRequest) => {
   if (jsonError) return jsonError;
   const result = z.safeParse(onboardingSchema, body);
   if (!result.success) {
-    return apiError("Ungültige Eingabe", 422);
+    return apiError("Invalid input", 422);
   }
 
   const data: Record<string, unknown> = {

src/app/api/settings/account/route.ts

@@ -20,12 +20,12 @@ export const DELETE = apiHandler(async (request: NextRequest) => {
     const body = await request.json();
     confirm = typeof body?.confirm === "string" ? body.confirm : "";
   } catch {
-    return apiError("Ungueltige Anfrage", 422);
+    return apiError("Invalid request", 422);
   }
 
   if (confirm !== "DELETE_ACCOUNT") {
     return apiError(
-      "Bestaetigung fehlt. Sende { confirm: 'DELETE_ACCOUNT' }",
+      "Confirmation missing. Send { confirm: 'DELETE_ACCOUNT' }",
       422,
     );
   }
@@ -35,7 +35,7 @@ export const DELETE = apiHandler(async (request: NextRequest) => {
     const adminCount = await prisma.user.count({ where: { role: "ADMIN" } });
     if (adminCount <= 1) {
       return apiError(
-        "Der letzte Admin-Account kann nicht geloescht werden",
+        "The last admin account cannot be deleted",
         400,
       );
     }

src/app/api/settings/data/route.ts

@@ -18,11 +18,11 @@ export const DELETE = apiHandler(async (request: NextRequest) => {
     const body = await request.json();
     confirm = typeof body?.confirm === "string" ? body.confirm : "";
   } catch {
-    return apiError("Ungueltige Anfrage", 422);
+    return apiError("Invalid request", 422);
   }
 
   if (confirm !== "DELETE") {
-    return apiError("Bestaetigung fehlt", 422);
+    return apiError("Confirmation missing", 422);
   }
 
   const userId = user.id;

src/app/api/settings/moodlog/route.ts

@@ -21,7 +21,7 @@ export const PUT = apiHandler(async (request: NextRequest) => {
 
   const parsed = moodLogCredentialsSchema.safeParse(body);
   if (!parsed.success) {
-    return apiError("Ungueltige Eingabe", 422);
+    return apiError("Invalid input", 422);
   }
 
   const { url, apiKey } = parsed.data;

src/app/api/settings/ntfy/route.ts

@@ -51,13 +51,13 @@ export const PUT = apiHandler(async (request: NextRequest) => {
 
   if (jsonError) return jsonError;
   const parsed = ntfySettingsSchema.safeParse(body);
-  if (!parsed.success) return apiError("Ungueltige Daten", 422);
+  if (!parsed.success) return apiError("Invalid data", 422);
 
   const { serverUrl, topic, authToken, enabled } = parsed.data;
 
   if (enabled && (!serverUrl || !topic)) {
     return apiError(
-      "Server-URL und Topic sind erforderlich, wenn ntfy aktiviert ist",
+      "Server URL and topic are required when ntfy is enabled",
       422,
     );
   }

src/app/api/settings/ntfy/test/route.ts

@@ -15,7 +15,7 @@ export const POST = apiHandler(async () => {
 
   const rl = await checkRateLimit(`ntfy-test:${user.id}`, 5, 5 * 60 * 1000);
   if (!rl.allowed) {
-    return apiError("Maximal 5 Tests in 5 Minuten", 429);
+    return apiError("Maximum 5 tests in 5 minutes", 429);
   }
 
   const channel = await prisma.notificationChannel.findUnique({
@@ -25,13 +25,13 @@ export const POST = apiHandler(async () => {
   });
 
   if (!channel) {
-    return apiError("ntfy ist nicht konfiguriert", 400);
+    return apiError("ntfy is not configured", 400);
   }
 
   const config = JSON.parse(decrypt(channel.config)) as NtfyChannelConfig;
 
   if (!config.serverUrl || !config.topic) {
-    return apiError("Server-URL und Topic sind erforderlich", 400);
+    return apiError("Server URL and topic are required", 400);
   }
 
   const success = await sendViaNtfy(config, {
@@ -39,11 +39,11 @@ export const POST = apiHandler(async () => {
     userId: user.id,
     title: "HealthLog Test",
     message:
-      "HealthLog: Verbindung erfolgreich! ntfy-Benachrichtigungen sind aktiv.",
+      "HealthLog: Connection successful! ntfy notifications are active.",
   });
 
   if (!success) {
-    return apiError("Testnachricht konnte nicht gesendet werden", 500);
+    return apiError("Failed to send test message", 500);
   }
 
   annotate({ action: { name: "settings.ntfy.test" }, meta: { success: true } });

src/app/api/settings/telegram/route.ts

@@ -47,14 +47,14 @@ export const PUT = apiHandler(async (request: NextRequest) => {
       telegramEnabled: true,
     },
   });
-  if (!current) return apiError("Benutzer nicht gefunden", 404);
+  if (!current) return apiError("User not found", 404);
 
   const { data: body, error: jsonError } = await safeJson(request);
 
   if (jsonError) return jsonError;
   const result = z.safeParse(telegramSettingsSchema, body);
   if (!result.success) {
-    return apiError("Ungueltige Eingabe", 422);
+    return apiError("Invalid input", 422);
   }
 
   const { botToken, chatId, enabled } = result.data;
@@ -68,7 +68,7 @@ export const PUT = apiHandler(async (request: NextRequest) => {
 
   if (enabled && (!hasTokenAfter || !hasChatIdAfter)) {
     return apiError(
-      "Fuer aktiviertes Telegram werden Bot-Token und Chat-ID benoetigt",
+      "Bot token and chat ID are required when Telegram is enabled",
       422,
     );
   }
@@ -82,7 +82,7 @@ export const PUT = apiHandler(async (request: NextRequest) => {
     const appUrl = process.env.APP_URL ?? process.env.NEXT_PUBLIC_APP_URL;
     if (!appUrl) {
       return apiError(
-        "Server-Konfiguration fehlerhaft: APP_URL (oder NEXT_PUBLIC_APP_URL) fehlt.",
+        "Server configuration error: APP_URL (or NEXT_PUBLIC_APP_URL) is missing.",
         500,
       );
     }
@@ -92,14 +92,14 @@ export const PUT = apiHandler(async (request: NextRequest) => {
       appBaseUrl = new URL(appUrl);
     } catch {
       return apiError(
-        "Server-Konfiguration fehlerhaft: APP_URL ist ungueltig.",
+        "Server configuration error: APP_URL is invalid.",
         500,
       );
     }
 
     if (appBaseUrl.protocol !== "https:") {
       return apiError(
-        "Telegram-Webhook benoetigt eine oeffentliche HTTPS-URL (kein http/localhost).",
+        "Telegram webhook requires a public HTTPS URL (no http/localhost).",
         422,
       );
     }
@@ -107,7 +107,7 @@ export const PUT = apiHandler(async (request: NextRequest) => {
     const localHosts = new Set(["localhost", "127.0.0.1", "::1"]);
     if (localHosts.has(appBaseUrl.hostname.toLowerCase())) {
       return apiError(
-        "Telegram-Webhook benoetigt eine oeffentlich erreichbare Domain (localhost ist nicht erlaubt).",
+        "Telegram webhook requires a publicly reachable domain (localhost is not allowed).",
         422,
       );
     }
@@ -117,7 +117,7 @@ export const PUT = apiHandler(async (request: NextRequest) => {
       !["80", "88", "443", "8443"].includes(appBaseUrl.port)
     ) {
       return apiError(
-        "Telegram-Webhook erlaubt nur die Ports 80, 88, 443 oder 8443.",
+        "Telegram webhook only allows ports 80, 88, 443, or 8443.",
         422,
       );
     }
@@ -131,7 +131,7 @@ export const PUT = apiHandler(async (request: NextRequest) => {
     );
     if (!ok) {
       return apiError(
-        "Telegram-Webhook konnte nicht gesetzt werden. Pruefe Bot-Token und Erreichbarkeit.",
+        "Failed to set Telegram webhook. Check bot token and reachability.",
         422,
       );
     }

src/app/api/settings/telegram/test/route.ts

@@ -14,7 +14,7 @@ export const POST = apiHandler(async () => {
 
   const rl = await checkRateLimit(`telegram-test:${user.id}`, 5, 5 * 60 * 1000);
   if (!rl.allowed) {
-    return apiError("Maximal 5 Tests in 5 Minuten", 429);
+    return apiError("Maximum 5 tests in 5 minutes", 429);
   }
 
   const dbUser = await prisma.user.findUnique({
@@ -24,7 +24,7 @@ export const POST = apiHandler(async () => {
 
   if (!dbUser?.telegramBotToken || !dbUser?.telegramChatId) {
     return apiError(
-      "Bot-Token und Chat-ID muessen zuerst gespeichert werden",
+      "Bot token and chat ID must be saved first",
       422,
     );
   }
@@ -33,12 +33,12 @@ export const POST = apiHandler(async () => {
   const ok = await sendTelegramMessage(
     botToken,
     dbUser.telegramChatId,
-    "HealthLog: Verbindung erfolgreich! Telegram-Benachrichtigungen sind aktiv.",
+    "HealthLog: Connection successful! Telegram notifications are active.",
   );
 
   if (!ok) {
     return apiError(
-      "Nachricht konnte nicht gesendet werden. Pruefe Bot-Token und Chat-ID.",
+      "Failed to send message. Check bot token and chat ID.",
       422,
     );
   }

src/app/api/tokens/[id]/route.ts

@@ -14,14 +14,14 @@ export const DELETE = apiHandler(async (_request: Request, { params }: RoutePara
   annotate({ action: { name: "tokens.revoke" } });
 
   if (!(await isApiGloballyEnabled())) {
-    return apiError("API ist global deaktiviert", 403);
+    return apiError("API is globally disabled", 403);
   }
 
   const { id } = await params;
   const token = await prisma.apiToken.findUnique({ where: { id } });
 
   if (!token || token.userId !== user.id) {
-    return apiError("Token nicht gefunden", 404);
+    return apiError("Token not found", 404);
   }
 
   await prisma.apiToken.update({

src/app/api/tokens/route.ts

@@ -9,7 +9,7 @@ import { NextRequest } from "next/server";
 import { z } from "zod/v4";
 
 const createTokenSchema = z.object({
-  name: z.string().min(1, "Name erforderlich").max(100),
+  name: z.string().min(1, "Name required").max(100),
   expiresInDays: z.number().int().min(1).max(365).optional(),
 });
 
@@ -18,7 +18,7 @@ export const GET = apiHandler(async () => {
   annotate({ action: { name: "tokens.list" } });
 
   if (!(await isApiGloballyEnabled())) {
-    return apiError("API ist global deaktiviert", 403);
+    return apiError("API is globally disabled", 403);
   }
 
   const tokens = await prisma.apiToken.findMany({
@@ -43,7 +43,7 @@ export const POST = apiHandler(async (request: NextRequest) => {
   annotate({ action: { name: "tokens.create" } });
 
   if (!(await isApiGloballyEnabled())) {
-    return apiError("API ist global deaktiviert", 403);
+    return apiError("API is globally disabled", 403);
   }
 
   const { data: body, error: jsonError } = await safeJson(request);

src/app/api/withings/credentials/route.ts

@@ -41,7 +41,7 @@ export const PUT = apiHandler(async (request: NextRequest) => {
   if (jsonError) return jsonError;
   const result = z.safeParse(withingsCredentialsSchema, body);
   if (!result.success) {
-    return apiError("Client-ID und Client-Secret sind erforderlich", 422);
+    return apiError("Client ID and Client Secret are required", 422);
   }
 
   await prisma.user.update({

src/app/api/withings/disconnect/route.ts

@@ -19,7 +19,7 @@ export const POST = apiHandler(async () => {
   });
 
   if (!connection) {
-    return apiError("Keine Withings-Verbindung vorhanden", 404);
+    return apiError("No Withings connection", 404);
   }
 
   // Try to unsubscribe webhook (best-effort)