diff --git a/src/app/api/integrations/moodlog/test/__tests__/route.test.ts b/src/app/api/integrations/moodlog/test/__tests__/route.test.ts
new file mode 100644
index 000000000..b2a77a689
--- /dev/null
+++ b/src/app/api/integrations/moodlog/test/__tests__/route.test.ts
@@ -0,0 +1,155 @@
+import { describe, it, expect, vi, beforeEach, afterEach } from "vitest";
+
+vi.mock("@/lib/api-handler", () => ({
+  apiHandler: <T extends (...args: unknown[]) => unknown>(fn: T) => fn,
+  requireAuth: vi.fn(async () => ({
+    user: { id: "u-1" },
+    session: { id: "s-1" },
+  })),
+}));
+
+vi.mock("@/lib/db", () => ({
+  prisma: {
+    user: {
+      findUnique: vi.fn(),
+    },
+  },
+}));
+
+vi.mock("@/lib/rate-limit", () => ({
+  checkRateLimit: vi.fn(async () => ({ allowed: true })),
+}));
+
+vi.mock("@/lib/logging/context", () => ({
+  annotate: vi.fn(),
+}));
+
+vi.mock("@/lib/crypto", () => ({
+  decrypt: vi.fn((x: string) => x),
+}));
+
+import { POST } from "../route";
+import { prisma } from "@/lib/db";
+import { checkRateLimit } from "@/lib/rate-limit";
+
+interface ApiErrorEnvelope {
+  data: null;
+  error: string;
+}
+interface ApiSuccessEnvelope<T> {
+  data: T;
+  error: null;
+}
+
+const originalFetch = global.fetch;
+
+beforeEach(() => {
+  vi.mocked(checkRateLimit).mockResolvedValue({
+    allowed: true,
+    remaining: 5,
+    resetAt: Date.now() + 60_000,
+  } as never);
+  vi.mocked(prisma.user.findUnique).mockReset();
+  global.fetch = vi.fn() as never;
+});
+
+afterEach(() => {
+  global.fetch = originalFetch;
+});
+
+function emptyRequest(): Request {
+  return new Request("http://localhost/api/integrations/moodlog/test", {
+    method: "POST",
+    headers: { "content-length": "0" },
+  });
+}
+
+describe("POST /api/integrations/moodlog/test", () => {
+  it("happy path returns ok with shape", async () => {
+    const lastSyncedAt = new Date("2026-05-01T10:00:00.000Z");
+    vi.mocked(prisma.user.findUnique).mockResolvedValueOnce({
+      moodLogUrlEncrypted: "https://example.com",
+      moodLogApiKeyEncrypted: "ml-key-123",
+      moodLogLastSyncedAt: lastSyncedAt,
+    } as never);
+    (global.fetch as unknown as ReturnType<typeof vi.fn>).mockResolvedValueOnce(
+      new Response(JSON.stringify({ entries: [] }), { status: 200 }),
+    );
+
+    const response = await POST(emptyRequest() as never);
+    expect(response.status).toBe(200);
+    const body = (await response.json()) as ApiSuccessEnvelope<{
+      ok: boolean;
+      statusCode: number;
+      latencyMs: number;
+      lastSyncedAt: string;
+    }>;
+    expect(body.data.ok).toBe(true);
+    expect(body.data.statusCode).toBe(200);
+    expect(typeof body.data.latencyMs).toBe("number");
+    expect(body.data.lastSyncedAt).toBe(lastSyncedAt.toISOString());
+
+    // Probe must hit the actual sync endpoint with Bearer auth, not a bare HEAD
+    // against the configured URL.
+    const fetchCall = (global.fetch as unknown as ReturnType<typeof vi.fn>).mock
+      .calls[0];
+    const init = fetchCall[1] as RequestInit;
+    expect(init.method).toBe("GET");
+    const headers = init.headers as Record<string, string>;
+    expect(headers.Authorization).toBe("Bearer ml-key-123");
+    expect(init.redirect).toBe("manual");
+  });
+
+  it("rate-limit denial returns 429 with no upstream call", async () => {
+    vi.mocked(checkRateLimit).mockResolvedValueOnce({
+      allowed: false,
+      remaining: 0,
+      resetAt: Date.now() + 60_000,
+    } as never);
+    const response = await POST(emptyRequest() as never);
+    expect(response.status).toBe(429);
+    expect(global.fetch).not.toHaveBeenCalled();
+  });
+
+  it("returns 422 when no moodLog URL configured", async () => {
+    vi.mocked(prisma.user.findUnique).mockResolvedValueOnce({
+      moodLogUrlEncrypted: null,
+      moodLogApiKeyEncrypted: null,
+      moodLogLastSyncedAt: null,
+    } as never);
+    const response = await POST(emptyRequest() as never);
+    expect(response.status).toBe(422);
+    const body = (await response.json()) as ApiErrorEnvelope;
+    expect(body.error).toMatch(/not configured/i);
+    expect(global.fetch).not.toHaveBeenCalled();
+  });
+
+  it("rejects SSRF (private IP) with 422", async () => {
+    vi.mocked(prisma.user.findUnique).mockResolvedValueOnce({
+      moodLogUrlEncrypted: "http://127.0.0.1/moodlog",
+      moodLogApiKeyEncrypted: "ml-key-123",
+      moodLogLastSyncedAt: null,
+    } as never);
+    const response = await POST(emptyRequest() as never);
+    expect(response.status).toBe(422);
+    expect(global.fetch).not.toHaveBeenCalled();
+  });
+
+  it("does not leak upstream URL or Bearer token on upstream rejection", async () => {
+    vi.mocked(prisma.user.findUnique).mockResolvedValueOnce({
+      moodLogUrlEncrypted: "https://example.com",
+      moodLogApiKeyEncrypted: "sk-secret",
+      moodLogLastSyncedAt: null,
+    } as never);
+    (global.fetch as unknown as ReturnType<typeof vi.fn>).mockRejectedValueOnce(
+      new Error(
+        "Authorization: Bearer sk-secret echoed from https://example.com/api/integrations/health-log/mood",
+      ),
+    );
+    const response = await POST(emptyRequest() as never);
+    const text = await response.text();
+    expect(response.status).toBe(502);
+    expect(text).not.toMatch(/sk-/);
+    expect(text).not.toMatch(/example\.com/);
+  });
+});
diff --git a/src/app/api/integrations/moodlog/test/route.ts b/src/app/api/integrations/moodlog/test/route.ts
new file mode 100644
index 000000000..076cf956a
--- /dev/null
+++ b/src/app/api/integrations/moodlog/test/route.ts
@@ -0,0 +1,173 @@
+import type { NextRequest } from "next/server";
+import { apiHandler, requireAuth } from "@/lib/api-handler";
+import { apiSuccess, apiError } from "@/lib/api-response";
+import { checkRateLimit } from "@/lib/rate-limit";
+import { annotate } from "@/lib/logging/context";
+import { prisma } from "@/lib/db";
+import { decrypt } from "@/lib/crypto";
+import { isPublicUrl } from "@/lib/validations/notifications";
+
+export const dynamic = "force-dynamic";
+
+const TIMEOUT_MS = 5_000;
+
+function categoriseHttpStatus(status: number): {
+  code: string;
+  message: string;
+} {
+  if (status === 401 || status === 403) {
+    return {
+      code: "credentials_rejected",
+      message: "moodLog rejected the API key",
+    };
+  }
+  if (status === 404) {
+    return {
+      code: "endpoint_not_found",
+      message: "moodLog endpoint not found at the configured URL",
+    };
+  }
+  if (status === 429) {
+    return {
+      code: "rate_limited",
+      message: "moodLog rate-limited the request",
+    };
+  }
+  if (status >= 500) {
+    return {
+      code: "upstream_error",
+      message: "moodLog returned a server error",
+    };
+  }
+  return { code: "connection_failed", message: "moodLog connection failed" };
+}
+
+function redact(text: string): string {
+  return text
+    .replace(/Bearer\s+\S+/gi, "Bearer [REDACTED]")
+    .replace(/https?:\/\/\S+/gi, "[url]");
+}
+
+export const POST = apiHandler(async (_request: NextRequest) => {
+  const { user } = await requireAuth();
+  annotate({ action: { name: "integrations.moodlog.test" } });
+
+  const rl = await checkRateLimit(`moodlog-test:${user.id}`, 5, 60_000);
+  if (!rl.allowed) {
+    return apiError("Too many test requests", 429, {
+      errorCode: "rate_limited_self",
+    });
+  }
+
+  const dbUser = await prisma.user.findUnique({
+    where: { id: user.id },
+    select: {
+      moodLogUrlEncrypted: true,
+      moodLogApiKeyEncrypted: true,
+      moodLogLastSyncedAt: true,
+    },
+  });
+
+  if (!dbUser?.moodLogUrlEncrypted || !dbUser.moodLogApiKeyEncrypted) {
+    return apiError("moodLog not configured", 422, {
+      errorCode: "not_configured",
+    });
+  }
+
+  let baseUrl: string;
+  let apiKey: string;
+  try {
+    baseUrl = decrypt(dbUser.moodLogUrlEncrypted);
+    apiKey = decrypt(dbUser.moodLogApiKeyEncrypted);
+  } catch {
+    return apiError("moodLog credentials unreadable", 422, {
+      errorCode: "credentials_unreadable",
+    });
+  }
+
+  if (!isPublicUrl(baseUrl)) {
+    return apiError("moodLog URL must be a public HTTP(S) endpoint", 422, {
+      errorCode: "url_not_public",
+    });
+  }
+
+  // Probe the actual sync endpoint with the actual auth header — a HEAD on the
+  // bare URL would return 200 from the static landing page even if the API key
+  // is invalid. Use a 1-day window to keep the upstream payload small.
+  let probeUrl: URL;
+  try {
+    probeUrl = new URL("/api/integrations/health-log/mood", baseUrl);
+  } catch {
+    return apiError("moodLog URL is invalid", 422, {
+      errorCode: "url_invalid",
+    });
+  }
+  const yesterday = new Date(Date.now() - 24 * 3600 * 1000)
+    .toISOString()
+    .slice(0, 10);
+  const today = new Date().toISOString().slice(0, 10);
+  probeUrl.searchParams.set("from", yesterday);
+  probeUrl.searchParams.set("to", today);
+
+  const controller = new AbortController();
+  const timer = setTimeout(() => controller.abort(), TIMEOUT_MS);
+  const start = performance.now();
+
+  try {
+    const res = await fetch(probeUrl.toString(), {
+      method: "GET",
+      headers: { Authorization: `Bearer ${apiKey}` },
+      signal: controller.signal,
+      cache: "no-store",
+      // `manual` neutralises the redirect-follow SSRF where a public host
+      // serves a 302 to 169.254.169.254 (cloud metadata) or RFC1918 ranges.
+      redirect: "manual",
+    });
+    const latencyMs = Math.round(performance.now() - start);
+
+    // 3xx in `manual` redirect mode → we never followed; treat as success
+    // failure rather than chase the Location header.
+    if (res.status >= 300 && res.status < 400) {
+      annotate({ meta: { moodlog_test_status: res.status } });
+      return apiError("moodLog redirected — check the configured URL", 502, {
+        errorCode: "redirected",
+      });
+    }
+
+    if (!res.ok) {
+      const cat = categoriseHttpStatus(res.status);
+      annotate({
+        meta: {
+          moodlog_test_status: res.status,
+          moodlog_test_code: cat.code,
+          moodlog_test_latency_ms: latencyMs,
+        },
+      });
+      return apiError(cat.message, 502, { errorCode: cat.code });
+    }
+
+    return apiSuccess({
+      ok: true,
+      statusCode: res.status,
+      latencyMs,
+      lastSyncedAt: dbUser.moodLogLastSyncedAt,
+    });
+  } catch (e) {
+    const err = e as Error;
+    const isAbort = err.name === "AbortError";
+    const code = isAbort ? "timeout" : "connection_failed";
+    annotate({
+      meta: {
+        moodlog_test_code: code,
+        moodlog_test_error: redact(err.message).slice(0, 300),
+      },
+    });
+    return apiError(
+      isAbort ? "moodLog request timed out" : "moodLog connection failed",
+      502,
+      { errorCode: code },
+    );
+  } finally {
+    clearTimeout(timer);
+  }
+});
diff --git a/src/app/api/integrations/withings/test/__tests__/route.test.ts b/src/app/api/integrations/withings/test/__tests__/route.test.ts
new file mode 100644
index 000000000..bfacf8dec
--- /dev/null
+++ b/src/app/api/integrations/withings/test/__tests__/route.test.ts
@@ -0,0 +1,142 @@
+import { describe, it, expect, vi, beforeEach, afterEach } from "vitest";
+
+vi.mock("@/lib/api-handler", () => ({
+  apiHandler: <T extends (...args: unknown[]) => unknown>(fn: T) => fn,
+  requireAuth: vi.fn(async () => ({
+    user: { id: "u-1" },
+    session: { id: "s-1" },
+  })),
+}));
+
+vi.mock("@/lib/db", () => ({
+  prisma: {
+    withingsConnection: {
+      findUnique: vi.fn(),
+    },
+  },
+}));
+
+vi.mock("@/lib/rate-limit", () => ({
+  checkRateLimit: vi.fn(async () => ({ allowed: true })),
+}));
+
+vi.mock("@/lib/logging/context", () => ({
+  annotate: vi.fn(),
+}));
+
+vi.mock("@/lib/crypto", () => ({
+  decrypt: vi.fn((x: string) => x),
+}));
+
+vi.mock("@/lib/withings/sync", () => ({
+  getValidToken: vi.fn(),
+}));
+
+import { POST } from "../route";
+import { prisma } from "@/lib/db";
+import { checkRateLimit } from "@/lib/rate-limit";
+import { getValidToken } from "@/lib/withings/sync";
+
+interface ApiErrorEnvelope {
+  data: null;
+  error: string;
+}
+interface ApiSuccessEnvelope<T> {
+  data: T;
+  error: null;
+}
+
+const originalFetch = global.fetch;
+
+beforeEach(() => {
+  vi.mocked(checkRateLimit).mockResolvedValue({
+    allowed: true,
+    remaining: 5,
+    resetAt: Date.now() + 60_000,
+  } as never);
+  vi.mocked(prisma.withingsConnection.findUnique).mockReset();
+  vi.mocked(getValidToken).mockReset();
+  global.fetch = vi.fn() as never;
+});
+
+afterEach(() => {
+  global.fetch = originalFetch;
+});
+
+function emptyRequest(): Request {
+  return new Request("http://localhost/api/integrations/withings/test", {
+    method: "POST",
+    headers: { "content-length": "0" },
+  });
+}
+
+describe("POST /api/integrations/withings/test", () => {
+  it("happy path returns ok with shape", async () => {
+    const lastSyncedAt = new Date("2026-05-01T10:00:00.000Z");
+    vi.mocked(getValidToken).mockResolvedValueOnce({
+      accessToken: "plain-access",
+      connection: { id: "wc-1", withingsUserId: "wu-1" },
+    });
+    vi.mocked(prisma.withingsConnection.findUnique).mockResolvedValueOnce({
+      lastSyncedAt,
+    } as never);
+    (global.fetch as unknown as ReturnType<typeof vi.fn>).mockResolvedValueOnce(
+      new Response(JSON.stringify({ status: 0, body: {} }), { status: 200 }),
+    );
+
+    const response = await POST(emptyRequest() as never);
+    expect(response.status).toBe(200);
+    const body = (await response.json()) as ApiSuccessEnvelope<{
+      ok: boolean;
+      lastSyncedAt: string;
+      latencyMs: number;
+    }>;
+    expect(body.data.ok).toBe(true);
+    expect(typeof body.data.latencyMs).toBe("number");
+    expect(body.data.lastSyncedAt).toBe(lastSyncedAt.toISOString());
+  });
+
+  it("rate-limit denial returns 429 with no upstream call", async () => {
+    vi.mocked(checkRateLimit).mockResolvedValueOnce({
+      allowed: false,
+      remaining: 0,
+      resetAt: Date.now() + 60_000,
+    } as never);
+    const response = await POST(emptyRequest() as never);
+    expect(response.status).toBe(429);
+    expect(global.fetch).not.toHaveBeenCalled();
+  });
+
+  it("returns 422 when no Withings connection exists", async () => {
+    vi.mocked(getValidToken).mockResolvedValueOnce(null);
+    const response = await POST(emptyRequest() as never);
+    expect(response.status).toBe(422);
+    const body = (await response.json()) as ApiErrorEnvelope;
+    expect(body.error).toMatch(/not connected/i);
+    expect(global.fetch).not.toHaveBeenCalled();
+  });
+
+  it("sanitises 401 upstream — does not leak Bearer token or upstream URL", async () => {
+    vi.mocked(getValidToken).mockResolvedValueOnce({
+      accessToken: "sk-secret",
+      connection: { id: "wc-1", withingsUserId: "wu-1" },
+    });
+    vi.mocked(prisma.withingsConnection.findUnique).mockResolvedValueOnce({
+      lastSyncedAt: null,
+    } as never);
+    (global.fetch as unknown as ReturnType<typeof vi.fn>).mockResolvedValueOnce(
+      new Response(
+        JSON.stringify({
+          error: "Authorization: Bearer sk-secret echoed",
+          url: "https://wbsapi.withings.net/measure",
+        }),
+        { status: 401 },
+      ),
+    );
+    const response = await POST(emptyRequest() as never);
+    const text = await response.text();
+    expect(response.status).toBe(502);
+    expect(text).not.toMatch(/sk-/);
+    expect(text).not.toMatch(/wbsapi\.withings\.net/);
+  });
+});
diff --git a/src/app/api/integrations/withings/test/route.ts b/src/app/api/integrations/withings/test/route.ts
new file mode 100644
index 000000000..355f2af94
--- /dev/null
+++ b/src/app/api/integrations/withings/test/route.ts
@@ -0,0 +1,181 @@
+import type { NextRequest } from "next/server";
+import { apiHandler, requireAuth } from "@/lib/api-handler";
+import { apiSuccess, apiError } from "@/lib/api-response";
+import { checkRateLimit } from "@/lib/rate-limit";
+import { annotate } from "@/lib/logging/context";
+import { prisma } from "@/lib/db";
+import { getValidToken } from "@/lib/withings/sync";
+
+export const dynamic = "force-dynamic";
+
+const WITHINGS_MEASURE_URL = "https://wbsapi.withings.net/measure";
+const TIMEOUT_MS = 5_000;
+
+type CategorisedError = { code: string; message: string };
+
+function categoriseHttpStatus(status: number): CategorisedError {
+  if (status === 401 || status === 403) {
+    return {
+      code: "credentials_rejected",
+      message: "Withings rejected the credentials",
+    };
+  }
+  if (status === 429) {
+    return {
+      code: "rate_limited",
+      message: "Withings rate-limited the request",
+    };
+  }
+  if (status >= 500) {
+    return {
+      code: "upstream_error",
+      message: "Withings returned a server error",
+    };
+  }
+  return { code: "connection_failed", message: "Withings connection failed" };
+}
+
+// Withings returns HTTP 200 with `status` in the JSON body to signal API-level
+// errors. Reference: https://developer.withings.com/api-reference/#section/Response-status
+function categoriseApiStatus(apiStatus: number): CategorisedError {
+  switch (apiStatus) {
+    case 100:
+    case 101:
+    case 102:
+    case 401:
+      return {
+        code: "credentials_rejected",
+        message: "Withings rejected the credentials",
+      };
+    case 601:
+      return {
+        code: "rate_limited",
+        message: "Withings rate-limited the request",
+      };
+    case 503:
+      return {
+        code: "upstream_error",
+        message: "Withings reported a temporary server error",
+      };
+    default:
+      return {
+        code: "upstream_error",
+        message: "Withings returned an error",
+      };
+  }
+}
+
+export const POST = apiHandler(async (_request: NextRequest) => {
+  const { user } = await requireAuth();
+  annotate({ action: { name: "integrations.withings.test" } });
+
+  const rl = await checkRateLimit(`withings-test:${user.id}`, 5, 60_000);
+  if (!rl.allowed) {
+    return apiError("Too many test requests", 429, {
+      errorCode: "rate_limited_self",
+    });
+  }
+
+  const tokenInfo = await getValidToken(user.id);
+  if (!tokenInfo) {
+    return apiError("Withings not connected", 422, {
+      errorCode: "not_configured",
+    });
+  }
+
+  const connection = await prisma.withingsConnection.findUnique({
+    where: { userId: user.id },
+    select: { lastSyncedAt: true },
+  });
+
+  const params = new URLSearchParams({
+    action: "getmeas",
+    meastypes: "1",
+    lastupdate: Math.floor(Date.now() / 1000 - 60).toString(),
+  });
+
+  const controller = new AbortController();
+  const timer = setTimeout(() => controller.abort(), TIMEOUT_MS);
+  const start = performance.now();
+
+  try {
+    const res = await fetch(WITHINGS_MEASURE_URL, {
+      method: "POST",
+      headers: {
+        "Content-Type": "application/x-www-form-urlencoded",
+        Authorization: `Bearer ${tokenInfo.accessToken}`,
+      },
+      body: params.toString(),
+      signal: controller.signal,
+      redirect: "manual",
+    });
+    const latencyMs = Math.round(performance.now() - start);
+
+    if (!res.ok) {
+      const cat = categoriseHttpStatus(res.status);
+      annotate({
+        meta: {
+          withings_test_status: res.status,
+          withings_test_code: cat.code,
+          withings_test_latency_ms: latencyMs,
+        },
+      });
+      return apiError(cat.message, 502, { errorCode: cat.code });
+    }
+
+    let json: { status?: number } = {};
+    try {
+      json = (await res.json()) as { status?: number };
+    } catch {
+      annotate({
+        meta: { withings_test_code: "upstream_invalid_json" },
+      });
+      return apiError("Withings returned an unparseable response", 502, {
+        errorCode: "upstream_invalid_json",
+      });
+    }
+
+    if (json.status !== 0) {
+      const apiStatus = json.status ?? -1;
+      const cat = categoriseApiStatus(apiStatus);
+      annotate({
+        meta: {
+          withings_test_api_status: apiStatus,
+          withings_test_code: cat.code,
+          withings_test_latency_ms: latencyMs,
+        },
+      });
+      return apiError(cat.message, 502, { errorCode: cat.code });
+    }
+
+    return apiSuccess({
+      ok: true,
+      lastSyncedAt: connection?.lastSyncedAt ?? null,
+      latencyMs,
+    });
+  } catch (e) {
+    const err = e as Error;
+    const isAbort = err.name === "AbortError";
+    const code = isAbort ? "timeout" : "connection_failed";
+    annotate({
+      meta: {
+        withings_test_code: code,
+        withings_test_error: redact(err.message).slice(0, 300),
+      },
+    });
+    return apiError(
+      isAbort ? "Withings request timed out" : "Withings connection failed",
+      502,
+      { errorCode: code },
+    );
+  } finally {
+    clearTimeout(timer);
+  }
+});
+
+// Strip any `Bearer <token>` substring before annotating; the catch path can
+// see DNS / TLS errors that include the request init via err.cause in some
+// runtimes, and we never want a token in Loki.
+function redact(text: string): string {
+  return text.replace(/Bearer\s+\S+/gi, "Bearer [REDACTED]");
+}
diff --git a/src/app/api/monitoring/glitchtip/test/__tests__/route.test.ts b/src/app/api/monitoring/glitchtip/test/__tests__/route.test.ts
new file mode 100644
index 000000000..3c4180b46
--- /dev/null
+++ b/src/app/api/monitoring/glitchtip/test/__tests__/route.test.ts
@@ -0,0 +1,164 @@
+import { describe, it, expect, vi, beforeEach, afterEach } from "vitest";
+
+vi.mock("@/lib/api-handler", () => ({
+  apiHandler: <T extends (...args: unknown[]) => unknown>(fn: T) => fn,
+  requireAdmin: vi.fn(async () => ({
+    user: { id: "u-admin" },
+    session: { id: "s-1" },
+  })),
+}));
+
+vi.mock("@/lib/db", () => ({
+  prisma: {
+    appSettings: {
+      findUnique: vi.fn(),
+    },
+  },
+}));
+
+vi.mock("@/lib/rate-limit", () => ({
+  checkRateLimit: vi.fn(async () => ({ allowed: true })),
+}));
+
+vi.mock("@/lib/logging/context", () => ({
+  annotate: vi.fn(),
+}));
+
+vi.mock("@/lib/crypto", () => ({
+  decrypt: vi.fn((x: string) => x),
+}));
+
+vi.mock("@/lib/monitoring/glitchtip", () => ({
+  sendGlitchtipEvent: vi.fn(),
+}));
+
+import { POST } from "../route";
+import { prisma } from "@/lib/db";
+import { checkRateLimit } from "@/lib/rate-limit";
+import { sendGlitchtipEvent } from "@/lib/monitoring/glitchtip";
+
+interface ApiErrorEnvelope {
+  data: null;
+  error: string;
+}
+interface ApiSuccessEnvelope<T> {
+  data: T;
+  error: null;
+}
+
+const originalFetch = global.fetch;
+
+beforeEach(() => {
+  vi.mocked(checkRateLimit).mockResolvedValue({
+    allowed: true,
+    remaining: 5,
+    resetAt: Date.now() + 60_000,
+  } as never);
+  vi.mocked(prisma.appSettings.findUnique).mockReset();
+  vi.mocked(sendGlitchtipEvent).mockReset();
+  global.fetch = vi.fn() as never;
+});
+
+afterEach(() => {
+  global.fetch = originalFetch;
+});
+
+function emptyRequest(): Request {
+  return new Request("http://localhost/api/monitoring/glitchtip/test", {
+    method: "POST",
+    headers: { "content-length": "0" },
+  });
+}
+
+describe("POST /api/monitoring/glitchtip/test", () => {
+  it("happy path returns ok with statusCode", async () => {
+    vi.mocked(prisma.appSettings.findUnique).mockResolvedValueOnce({
+      glitchtipDsn: "https://abc@glitch.example.com/1",
+    } as never);
+    vi.mocked(sendGlitchtipEvent).mockResolvedValueOnce({
+      ok: true,
+      method: "envelope",
+      status: 200,
+    });
+
+    const response = await POST(emptyRequest() as never);
+    expect(response.status).toBe(200);
+    const body = (await response.json()) as ApiSuccessEnvelope<{
+      ok: boolean;
+      statusCode: number;
+      latencyMs: number;
+    }>;
+    expect(body.data.ok).toBe(true);
+    expect(body.data.statusCode).toBe(200);
+    expect(typeof body.data.latencyMs).toBe("number");
+
+    // CRITICAL guard against the `id: "default"` typo regression.
+    expect(prisma.appSettings.findUnique).toHaveBeenCalledWith(
+      expect.objectContaining({ where: { id: "singleton" } }),
+    );
+  });
+
+  it("rejects HTTP DSN with 422", async () => {
+    vi.mocked(prisma.appSettings.findUnique).mockResolvedValueOnce({
+      glitchtipDsn: "http://abc@glitch.example.com/1",
+    } as never);
+    const response = await POST(emptyRequest() as never);
+    expect(response.status).toBe(422);
+    const body = (await response.json()) as ApiErrorEnvelope & {
+      meta: { errorCode: string };
+    };
+    expect(body.meta.errorCode).toBe("dsn_not_https");
+    expect(sendGlitchtipEvent).not.toHaveBeenCalled();
+  });
+
+  it("rejects DSN pointing at a private host (SSRF guard)", async () => {
+    vi.mocked(prisma.appSettings.findUnique).mockResolvedValueOnce({
+      glitchtipDsn: "https://abc@127.0.0.1/1",
+    } as never);
+    const response = await POST(emptyRequest() as never);
+    expect(response.status).toBe(422);
+    const body = (await response.json()) as ApiErrorEnvelope & {
+      meta: { errorCode: string };
+    };
+    expect(body.meta.errorCode).toBe("dsn_host_not_public");
+    expect(sendGlitchtipEvent).not.toHaveBeenCalled();
+  });
+
+  it("rate-limit denial returns 429 with no upstream call", async () => {
+    vi.mocked(checkRateLimit).mockResolvedValueOnce({
+      allowed: false,
+      remaining: 0,
+      resetAt: Date.now() + 60_000,
+    } as never);
+    const response = await POST(emptyRequest() as never);
+    expect(response.status).toBe(429);
+    expect(sendGlitchtipEvent).not.toHaveBeenCalled();
+  });
+
+  it("returns 422 when DSN is not configured", async () => {
+    vi.mocked(prisma.appSettings.findUnique).mockResolvedValueOnce({
+      glitchtipDsn: null,
+    } as never);
+    const response = await POST(emptyRequest() as never);
+    expect(response.status).toBe(422);
+    const body = (await response.json()) as ApiErrorEnvelope;
+    expect(body.error).toMatch(/not configured/i);
+    expect(sendGlitchtipEvent).not.toHaveBeenCalled();
+  });
+
+  it("does not leak DSN/Bearer/sk- on upstream 401", async () => {
+    vi.mocked(prisma.appSettings.findUnique).mockResolvedValueOnce({
+      glitchtipDsn: "https://abc@glitch.example.com/1",
+    } as never);
+    vi.mocked(sendGlitchtipEvent).mockRejectedValueOnce(
+      new Error(
+        "401 Unauthorized: Authorization: Bearer sk-secret from https://glitch.example.com/api/1/envelope/",
+      ),
+    );
+    const response = await POST(emptyRequest() as never);
+    const text = await response.text();
+    expect(response.status).toBe(502);
+    expect(text).not.toMatch(/sk-/);
+    expect(text).not.toMatch(/glitch\.example\.com/);
+  });
+});
diff --git a/src/app/api/monitoring/glitchtip/test/route.ts b/src/app/api/monitoring/glitchtip/test/route.ts
new file mode 100644
index 000000000..93c103afb
--- /dev/null
+++ b/src/app/api/monitoring/glitchtip/test/route.ts
@@ -0,0 +1,120 @@
+import type { NextRequest } from "next/server";
+import { apiHandler, requireAdmin } from "@/lib/api-handler";
+import { apiSuccess, apiError } from "@/lib/api-response";
+import { checkRateLimit } from "@/lib/rate-limit";
+import { annotate } from "@/lib/logging/context";
+import { prisma } from "@/lib/db";
+import { sendGlitchtipEvent } from "@/lib/monitoring/glitchtip";
+import { isPublicUrl } from "@/lib/validations/notifications";
+
+export const dynamic = "force-dynamic";
+
+const TIMEOUT_MS = 5_000;
+
+export const POST = apiHandler(async (_request: NextRequest) => {
+  const { user } = await requireAdmin();
+  annotate({ action: { name: "monitoring.glitchtip.test" } });
+
+  const rl = await checkRateLimit(`glitchtip-test:${user.id}`, 5, 60_000);
+  if (!rl.allowed) {
+    return apiError("Too many test requests", 429, {
+      errorCode: "rate_limited_self",
+    });
+  }
+
+  const settings = await prisma.appSettings.findUnique({
+    where: { id: "singleton" },
+    select: { glitchtipDsn: true },
+  });
+
+  if (!settings?.glitchtipDsn) {
+    return apiError("Glitchtip DSN not configured", 422, {
+      errorCode: "not_configured",
+    });
+  }
+
+  // DSN is admin-set, but a compromised/social-engineered admin (or a stored
+  // settings record from a hostile import) could aim Glitchtip at internal
+  // hosts. Validate the host is publicly reachable and uses HTTPS before we
+  // hand the URL to the helper.
+  let dsnHost: string;
+  try {
+    const parsed = new URL(settings.glitchtipDsn);
+    if (parsed.protocol !== "https:") {
+      return apiError("Glitchtip DSN must use HTTPS", 422, {
+        errorCode: "dsn_not_https",
+      });
+    }
+    if (!isPublicUrl(`${parsed.protocol}//${parsed.host}`)) {
+      return apiError("Glitchtip DSN host is not publicly reachable", 422, {
+        errorCode: "dsn_host_not_public",
+      });
+    }
+    dsnHost = parsed.host;
+  } catch {
+    return apiError("Glitchtip DSN is malformed", 422, {
+      errorCode: "dsn_invalid",
+    });
+  }
+
+  const start = performance.now();
+  const send = sendGlitchtipEvent({
+    dsn: settings.glitchtipDsn,
+    input: {
+      environment: process.env.NODE_ENV ?? "production",
+      message: "HealthLog Glitchtip self-test",
+      level: "info",
+      // sourceTag rides through into the event tags. Adding "noise: true" lets
+      // operators silence these in their inbound Glitchtip rules so the test
+      // button doesn't pollute the issue inbox.
+      sourceTag: "self-test:noise",
+    },
+  });
+
+  const timeoutErr = new Error("timeout");
+  timeoutErr.name = "AbortError";
+  const timeout = new Promise<never>((_, reject) =>
+    setTimeout(() => reject(timeoutErr), TIMEOUT_MS),
+  );
+
+  try {
+    const result = await Promise.race([send, timeout]);
+    const latencyMs = Math.round(performance.now() - start);
+
+    if (!result.ok) {
+      annotate({
+        meta: {
+          glitchtip_test_status: result.status ?? null,
+          glitchtip_test_method: result.method ?? null,
+          glitchtip_test_latency_ms: latencyMs,
+          glitchtip_test_host: dsnHost,
+        },
+      });
+      return apiError("Glitchtip rejected the event", 502, {
+        errorCode: "upstream_error",
+      });
+    }
+
+    return apiSuccess({
+      ok: true,
+      statusCode: result.status ?? 200,
+      latencyMs,
+    });
+  } catch (e) {
+    const err = e as Error;
+    const isTimeout = err.name === "AbortError";
+    const code = isTimeout ? "timeout" : "connection_failed";
+    annotate({
+      meta: {
+        glitchtip_test_code: code,
+        glitchtip_test_host: dsnHost,
+        glitchtip_test_error: err.message.slice(0, 200),
+      },
+    });
+    return apiError(
+      isTimeout ? "Glitchtip request timed out" : "Glitchtip connection failed",
+      502,
+      { errorCode: code },
+    );
+  }
+});
diff --git a/src/app/api/monitoring/umami/test/__tests__/route.test.ts b/src/app/api/monitoring/umami/test/__tests__/route.test.ts
new file mode 100644
index 000000000..689992b73
--- /dev/null
+++ b/src/app/api/monitoring/umami/test/__tests__/route.test.ts
@@ -0,0 +1,135 @@
+import { describe, it, expect, vi, beforeEach, afterEach } from "vitest";
+
+vi.mock("@/lib/api-handler", () => ({
+  apiHandler: <T extends (...args: unknown[]) => unknown>(fn: T) => fn,
+  requireAdmin: vi.fn(async () => ({
+    user: { id: "u-admin" },
+    session: { id: "s-1" },
+  })),
+}));
+
+vi.mock("@/lib/db", () => ({
+  prisma: {
+    appSettings: {
+      findUnique: vi.fn(),
+    },
+  },
+}));
+
+vi.mock("@/lib/rate-limit", () => ({
+  checkRateLimit: vi.fn(async () => ({ allowed: true })),
+}));
+
+vi.mock("@/lib/logging/context", () => ({
+  annotate: vi.fn(),
+}));
+
+vi.mock("@/lib/crypto", () => ({
+  decrypt: vi.fn((x: string) => x),
+}));
+
+import { POST } from "../route";
+import { prisma } from "@/lib/db";
+import { checkRateLimit } from "@/lib/rate-limit";
+
+interface ApiErrorEnvelope {
+  data: null;
+  error: string;
+}
+interface ApiSuccessEnvelope<T> {
+  data: T;
+  error: null;
+}
+
+const originalFetch = global.fetch;
+
+beforeEach(() => {
+  vi.mocked(checkRateLimit).mockResolvedValue({
+    allowed: true,
+    remaining: 5,
+    resetAt: Date.now() + 60_000,
+  } as never);
+  vi.mocked(prisma.appSettings.findUnique).mockReset();
+  global.fetch = vi.fn() as never;
+});
+
+afterEach(() => {
+  global.fetch = originalFetch;
+});
+
+function emptyRequest(): Request {
+  return new Request("http://localhost/api/monitoring/umami/test", {
+    method: "POST",
+    headers: { "content-length": "0" },
+  });
+}
+
+describe("POST /api/monitoring/umami/test", () => {
+  it("happy path returns ok with hasMarker=true", async () => {
+    vi.mocked(prisma.appSettings.findUnique).mockResolvedValueOnce({
+      umamiScriptUrl: "https://analytics.example.com/script.js",
+    } as never);
+    (global.fetch as unknown as ReturnType<typeof vi.fn>).mockResolvedValueOnce(
+      new Response("(function(){window.umami=function(){};})();", {
+        status: 200,
+      }),
+    );
+
+    const response = await POST(emptyRequest() as never);
+    expect(response.status).toBe(200);
+    const body = (await response.json()) as ApiSuccessEnvelope<{
+      ok: boolean;
+      statusCode: number;
+      hasMarker: boolean;
+    }>;
+    expect(body.data.ok).toBe(true);
+    expect(body.data.hasMarker).toBe(true);
+    expect(body.data.statusCode).toBe(200);
+
+    // CRITICAL guard: AppSettings is keyed on `id: "singleton"` everywhere
+    // else in the codebase. A typo here ("default") would silently make the
+    // route return 422 in prod even with valid settings.
+    expect(prisma.appSettings.findUnique).toHaveBeenCalledWith(
+      expect.objectContaining({ where: { id: "singleton" } }),
+    );
+  });
+
+  it("rate-limit denial returns 429 with no upstream call", async () => {
+    vi.mocked(checkRateLimit).mockResolvedValueOnce({
+      allowed: false,
+      remaining: 0,
+      resetAt: Date.now() + 60_000,
+    } as never);
+    const response = await POST(emptyRequest() as never);
+    expect(response.status).toBe(429);
+    expect(global.fetch).not.toHaveBeenCalled();
+  });
+
+  it("returns 422 when URL not configured", async () => {
+    vi.mocked(prisma.appSettings.findUnique).mockResolvedValueOnce({
+      umamiScriptUrl: null,
+    } as never);
+    const response = await POST(emptyRequest() as never);
+    expect(response.status).toBe(422);
+    const body = (await response.json()) as ApiErrorEnvelope;
+    expect(body.error).toMatch(/not configured/i);
+    expect(global.fetch).not.toHaveBeenCalled();
+  });
+
+  it("does not leak Bearer/sk- or upstream URL on upstream 401", async () => {
+    vi.mocked(prisma.appSettings.findUnique).mockResolvedValueOnce({
+      umamiScriptUrl: "https://analytics.example.com/script.js",
+    } as never);
+    (global.fetch as unknown as ReturnType<typeof vi.fn>).mockResolvedValueOnce(
+      new Response(
+        "Authorization: Bearer sk-secret echoed back from https://analytics.example.com/script.js",
+        { status: 401 },
+      ),
+    );
+    const response = await POST(emptyRequest() as never);
+    const text = await response.text();
+    expect(response.status).toBe(502);
+    expect(text).not.toMatch(/sk-/);
+    expect(text).not.toMatch(/analytics\.example\.com/);
+  });
+});
diff --git a/src/app/api/monitoring/umami/test/route.ts b/src/app/api/monitoring/umami/test/route.ts
new file mode 100644
index 000000000..6f1767648
--- /dev/null
+++ b/src/app/api/monitoring/umami/test/route.ts
@@ -0,0 +1,129 @@
+import type { NextRequest } from "next/server";
+import { apiHandler, requireAdmin } from "@/lib/api-handler";
+import { apiSuccess, apiError } from "@/lib/api-response";
+import { checkRateLimit } from "@/lib/rate-limit";
+import { annotate } from "@/lib/logging/context";
+import { prisma } from "@/lib/db";
+import { isPublicUrl } from "@/lib/validations/notifications";
+
+export const dynamic = "force-dynamic";
+
+const TIMEOUT_MS = 5_000;
+const MAX_BODY_BYTES = 256 * 1024;
+
+function redact(text: string): string {
+  return text.replace(/https?:\/\/\S+/gi, "[url]");
+}
+
+export const POST = apiHandler(async (_request: NextRequest) => {
+  const { user } = await requireAdmin();
+  annotate({ action: { name: "monitoring.umami.test" } });
+
+  const rl = await checkRateLimit(`umami-test:${user.id}`, 5, 60_000);
+  if (!rl.allowed) {
+    return apiError("Too many test requests", 429, {
+      errorCode: "rate_limited_self",
+    });
+  }
+
+  const settings = await prisma.appSettings.findUnique({
+    where: { id: "singleton" },
+    select: { umamiScriptUrl: true },
+  });
+
+  if (!settings?.umamiScriptUrl) {
+    return apiError("Umami script URL not configured", 422, {
+      errorCode: "not_configured",
+    });
+  }
+
+  const url = settings.umamiScriptUrl;
+  if (!isPublicUrl(url) || !url.startsWith("https://")) {
+    return apiError("Umami URL must be a public HTTPS endpoint", 422, {
+      errorCode: "url_not_public",
+    });
+  }
+
+  const controller = new AbortController();
+  const timer = setTimeout(() => controller.abort(), TIMEOUT_MS);
+  const start = performance.now();
+
+  try {
+    const res = await fetch(url, {
+      method: "GET",
+      signal: controller.signal,
+      cache: "no-store",
+      // `manual` neutralises a redirect-follow SSRF — even though the URL was
+      // checked with isPublicUrl(), a public host can 302 to a private IP.
+      redirect: "manual",
+    });
+    const latencyMs = Math.round(performance.now() - start);
+
+    if (res.status >= 300 && res.status < 400) {
+      annotate({ meta: { umami_test_status: res.status } });
+      return apiError("Umami URL redirects — check configuration", 502, {
+        errorCode: "redirected",
+      });
+    }
+
+    // Cap response read to 256 KB so a hostile public server can't stream
+    // gigabytes through us; combined with the 5 s abort, RAM use stays bounded.
+    let body = "";
+    if (res.body) {
+      const reader = res.body.getReader();
+      const decoder = new TextDecoder();
+      let total = 0;
+      try {
+        while (total < MAX_BODY_BYTES) {
+          const { done, value } = await reader.read();
+          if (done) break;
+          total += value.byteLength;
+          body += decoder.decode(value, { stream: true });
+        }
+        body += decoder.decode();
+      } finally {
+        reader.releaseLock();
+      }
+    }
+
+    if (!res.ok) {
+      annotate({
+        meta: {
+          umami_test_status: res.status,
+          umami_test_latency_ms: latencyMs,
+        },
+      });
+      return apiError("Umami connection failed", 502, {
+        errorCode: "upstream_error",
+      });
+    }
+
+    // Look for tracker-shape signal rather than a literal "umami" substring —
+    // a 404 page that mentions "Powered by Umami" would otherwise slip through.
+    const hasMarker = /umami\.track|window\.umami|"umami"/i.test(body);
+
+    return apiSuccess({
+      ok: hasMarker,
+      statusCode: res.status,
+      latencyMs,
+      hasMarker,
+    });
+  } catch (e) {
+    const err = e as Error;
+    const isAbort = err.name === "AbortError";
+    const code = isAbort ? "timeout" : "connection_failed";
+    annotate({
+      meta: {
+        umami_test_code: code,
+        umami_test_error: redact(err.message).slice(0, 300),
+      },
+    });
+    return apiError(
+      isAbort ? "Umami request timed out" : "Umami connection failed",
+      502,
+      { errorCode: code },
+    );
+  } finally {
+    clearTimeout(timer);
+  }
+});
diff --git a/src/app/api/notifications/web-push/test/__tests__/route.test.ts b/src/app/api/notifications/web-push/test/__tests__/route.test.ts
new file mode 100644
index 000000000..ba8532fe8
--- /dev/null
+++ b/src/app/api/notifications/web-push/test/__tests__/route.test.ts
@@ -0,0 +1,176 @@
+import { describe, it, expect, vi, beforeEach, afterEach } from "vitest";
+
+vi.mock("@/lib/api-handler", () => ({
+  apiHandler: <T extends (...args: unknown[]) => unknown>(fn: T) => fn,
+  requireAuth: vi.fn(async () => ({
+    user: { id: "u-1" },
+    session: { id: "s-1" },
+  })),
+}));
+
+vi.mock("@/lib/db", () => ({
+  prisma: {
+    pushSubscription: {
+      findFirst: vi.fn(),
+    },
+  },
+}));
+
+vi.mock("@/lib/rate-limit", () => ({
+  checkRateLimit: vi.fn(async () => ({ allowed: true })),
+}));
+
+vi.mock("@/lib/logging/context", () => ({
+  annotate: vi.fn(),
+}));
+
+vi.mock("@/lib/crypto", () => ({
+  decrypt: vi.fn((x: string) => x),
+}));
+
+vi.mock("@/lib/notifications/vapid-config", () => ({
+  getVapidConfig: vi.fn(async () => ({
+    subject: "mailto:test@example.com",
+    publicKey:
+      "BNcRdreALRFXTkOOUHK1EtK2wtaz5Ry4YfYCA_0QTpQtUbVlUls0VJXg7A8u-Ts1XbjhazAkj7I99e8QcYP7DkM",
+    privateKey: "private-key-stub",
+  })),
+}));
+
+const sendNotification = vi.fn();
+vi.mock("web-push", () => ({
+  default: {
+    setVapidDetails: vi.fn(),
+    sendNotification: (...args: unknown[]) => sendNotification(...args),
+  },
+  setVapidDetails: vi.fn(),
+  sendNotification: (...args: unknown[]) => sendNotification(...args),
+}));
+
+import { POST } from "../route";
+import { prisma } from "@/lib/db";
+import { checkRateLimit } from "@/lib/rate-limit";
+
+interface ApiErrorEnvelope {
+  data: null;
+  error: string;
+}
+interface ApiSuccessEnvelope<T> {
+  data: T;
+  error: null;
+}
+
+const originalFetch = global.fetch;
+
+beforeEach(() => {
+  vi.mocked(checkRateLimit).mockResolvedValue({
+    allowed: true,
+    remaining: 5,
+    resetAt: Date.now() + 60_000,
+  } as never);
+  vi.mocked(prisma.pushSubscription.findFirst).mockReset();
+  sendNotification.mockReset();
+  global.fetch = vi.fn() as never;
+});
+
+afterEach(() => {
+  global.fetch = originalFetch;
+});
+
+function emptyRequest(): Request {
+  return new Request("http://localhost/api/notifications/web-push/test", {
+    method: "POST",
+    headers: { "content-length": "0" },
+  });
+}
+
+describe("POST /api/notifications/web-push/test", () => {
+  it("happy path returns ok and sends to one subscription", async () => {
+    vi.mocked(prisma.pushSubscription.findFirst).mockResolvedValueOnce({
+      id: "p-1",
+      userId: "u-1",
+      endpoint: "https://fcm.googleapis.com/fcm/send/abc123token",
+      p256dh: "p256",
+      auth: "auth",
+    } as never);
+    sendNotification.mockResolvedValueOnce({ statusCode: 201 });
+
+    const response = await POST(emptyRequest() as never);
+    expect(response.status).toBe(200);
+    const body = (await response.json()) as ApiSuccessEnvelope<{
+      ok: boolean;
+      sent: number;
+      latencyMs: number;
+      perEndpoint: Array<{ host: string; status: number | null }>;
+    }>;
+    expect(body.data.ok).toBe(true);
+    expect(body.data.sent).toBe(1);
+    expect(body.data.perEndpoint).toHaveLength(1);
+    expect(body.data.perEndpoint[0].host).toBe("fcm.googleapis.com");
+    // never the full endpoint URL (the routing token is the only thing
+    // protecting that subscription from anyone who learns it).
+    const text = JSON.stringify(body);
+    expect(text).not.toMatch(/abc123token/);
+
+    // Spec: only the most-recent subscription gets the test push, not all.
+    expect(prisma.pushSubscription.findFirst).toHaveBeenCalledWith(
+      expect.objectContaining({
+        where: { userId: "u-1" },
+        orderBy: { createdAt: "desc" },
+      }),
+    );
+    expect(sendNotification).toHaveBeenCalledTimes(1);
+  });
+
+  it("rate-limit denial returns 429 with no upstream call", async () => {
+    vi.mocked(checkRateLimit).mockResolvedValueOnce({
+      allowed: false,
+      remaining: 0,
+      resetAt: Date.now() + 60_000,
+    } as never);
+    const response = await POST(emptyRequest() as never);
+    expect(response.status).toBe(429);
+    expect(sendNotification).not.toHaveBeenCalled();
+  });
+
+  it("returns 422 when no subscriptions registered", async () => {
+    vi.mocked(prisma.pushSubscription.findFirst).mockResolvedValueOnce(null);
+    const response = await POST(emptyRequest() as never);
+    expect(response.status).toBe(422);
+    const body = (await response.json()) as ApiErrorEnvelope;
+    expect(body.error).toMatch(/no push subscriptions/i);
+    expect(sendNotification).not.toHaveBeenCalled();
+  });
+
+  it("does not leak Bearer/sk- or full endpoint URL when upstream rejects", async () => {
+    vi.mocked(prisma.pushSubscription.findFirst).mockResolvedValueOnce({
+      id: "p-1",
+      userId: "u-1",
+      endpoint: "https://fcm.googleapis.com/fcm/send/abc123token",
+      p256dh: "p256",
+      auth: "auth",
+    } as never);
+    sendNotification.mockRejectedValueOnce(
+      Object.assign(
+        new Error(
+          "401 Unauthorized: Authorization: Bearer sk-secret from https://fcm.googleapis.com/fcm/send/abc123token",
+        ),
+        { statusCode: 401 },
+      ),
+    );
+    const response = await POST(emptyRequest() as never);
+    const text = await response.text();
+    expect(response.status).toBe(200);
+    expect(text).not.toMatch(/sk-/);
+    expect(text).not.toMatch(/abc123token/);
+    const parsed = JSON.parse(text) as ApiSuccessEnvelope<{
+      ok: boolean;
+      sent: number;
+      perEndpoint: Array<{ host: string; status: number | null }>;
+    }>;
+    expect(parsed.data.ok).toBe(false);
+    expect(parsed.data.sent).toBe(0);
+    expect(parsed.data.perEndpoint[0].host).toBe("fcm.googleapis.com");
+    expect(parsed.data.perEndpoint[0].status).toBe(401);
+  });
+});
diff --git a/src/app/api/notifications/web-push/test/route.ts b/src/app/api/notifications/web-push/test/route.ts
new file mode 100644
index 000000000..4ec620890
--- /dev/null
+++ b/src/app/api/notifications/web-push/test/route.ts
@@ -0,0 +1,103 @@
+import type { NextRequest } from "next/server";
+import { apiHandler, requireAuth } from "@/lib/api-handler";
+import { apiSuccess, apiError } from "@/lib/api-response";
+import { checkRateLimit } from "@/lib/rate-limit";
+import { annotate } from "@/lib/logging/context";
+import { prisma } from "@/lib/db";
+import { decrypt } from "@/lib/crypto";
+import { getVapidConfig } from "@/lib/notifications/vapid-config";
+
+export const dynamic = "force-dynamic";
+
+function hostFromEndpoint(endpoint: string): string {
+  try {
+    return new URL(endpoint).host;
+  } catch {
+    return "unknown";
+  }
+}
+
+// Strip any URL from a stringified web-push library error. Push providers (FCM,
+// Mozilla autopush, etc.) embed the full subscription endpoint into 410/404
+// error messages — that endpoint token is the routing secret, so it must never
+// land in our Wide Events.
+function redactPushError(text: string): string {
+  return text.replace(/https?:\/\/\S+/gi, "[endpoint]");
+}
+
+export const POST = apiHandler(async (_request: NextRequest) => {
+  const { user } = await requireAuth();
+  annotate({ action: { name: "notifications.web-push.test" } });
+
+  const rl = await checkRateLimit(`web-push-test:${user.id}`, 5, 60_000);
+  if (!rl.allowed) {
+    return apiError("Too many test requests", 429, {
+      errorCode: "rate_limited_self",
+    });
+  }
+
+  // Spec: only the most-recent subscription receives the test push. A user
+  // with phone + tablet + desktop should not get three buzzes per click.
+  const subscription = await prisma.pushSubscription.findFirst({
+    where: { userId: user.id },
+    orderBy: { createdAt: "desc" },
+  });
+
+  if (!subscription) {
+    return apiError("No push subscriptions registered", 422, {
+      errorCode: "not_configured",
+    });
+  }
+
+  const config = await getVapidConfig();
+  if (!config) {
+    return apiError("VAPID keys not configured", 422, {
+      errorCode: "vapid_not_configured",
+    });
+  }
+
+  const webpush = await import("web-push");
+  webpush.setVapidDetails(config.subject, config.publicKey, config.privateKey);
+
+  const pushPayload = JSON.stringify({
+    title: "HealthLog",
+    body: "This is a test notification from HealthLog",
+    tag: "self-test",
+  });
+
+  const host = hostFromEndpoint(subscription.endpoint);
+  const start = performance.now();
+
+  try {
+    const p256dh = decrypt(subscription.p256dh);
+    const auth = decrypt(subscription.auth);
+
+    const result = await webpush.sendNotification(
+      { endpoint: subscription.endpoint, keys: { p256dh, auth } },
+      pushPayload,
+    );
+    const latencyMs = Math.round(performance.now() - start);
+
+    return apiSuccess({
+      ok: true,
+      sent: 1,
+      latencyMs,
+      perEndpoint: [{ host, status: result.statusCode ?? 201 }],
+    });
+  } catch (err: unknown) {
+    const status = (err as { statusCode?: number }).statusCode ?? null;
+    const message = redactPushError((err as Error).message ?? "").slice(0, 200);
+    annotate({
+      meta: {
+        web_push_test_status: status,
+        web_push_test_host: host,
+        web_push_test_error: message,
+      },
+    });
+    return apiSuccess({
+      ok: false,
+      sent: 0,
+      perEndpoint: [{ host, status }],
+    });
+  }
+});
diff --git a/src/lib/api-response.ts b/src/lib/api-response.ts
index 4a27a5e74..68590c4c2 100644
--- a/src/lib/api-response.ts
+++ b/src/lib/api-response.ts
@@ -4,8 +4,22 @@ export function apiSuccess<T>(data: T, status = 200) {
   return NextResponse.json({ data, error: null }, { status });
 }
 
-export function apiError(message: string, status = 400) {
-  return NextResponse.json({ data: null, error: message }, { status });
+/**
+ * `meta` is additive — clients that ignore it see the unchanged
+ * `{ data: null, error: <string> }` envelope. New callers can pass
+ * `{ errorCode: "credentials_rejected" }` so the UI translates the message
+ * via `t("settings.testConnection.errors." + errorCode)` instead of
+ * displaying the server's English fallback.
+ */
+export function apiError(
+  message: string,
+  status = 400,
+  meta?: { errorCode?: string } & Record<string, unknown>,
+) {
+  return NextResponse.json(
+    { data: null, error: message, ...(meta ? { meta } : {}) },
+    { status },
+  );
 }
 
 /**
diff --git a/src/lib/withings/sync.ts b/src/lib/withings/sync.ts
index 1a6fa2e65..0afb7c6a3 100644
--- a/src/lib/withings/sync.ts
+++ b/src/lib/withings/sync.ts
@@ -27,7 +27,7 @@ export function getWithingsWebhookCallbackUrl(): string {
 /**
  * Get valid access token for a user, refreshing if expired.
  */
-async function getValidToken(userId: string): Promise<{
+export async function getValidToken(userId: string): Promise<{
   accessToken: string;
   connection: { id: string; withingsUserId: string };
 } | null> {
@@ -45,7 +45,9 @@ async function getValidToken(userId: string): Promise<{
     try {
       const creds = await getUserWithingsCredentials(userId);
       if (!creds) {
-        getEvent()?.addWarning(`No credentials found for user ${userId} during token refresh`);
+        getEvent()?.addWarning(
+          `No credentials found for user ${userId} during token refresh`,
+        );
         return null;
       }
 
@@ -161,6 +163,8 @@ export async function setupWebhook(userId: string): Promise<void> {
     );
     getEvent()?.addMeta("webhook_subscribed", userId);
   } catch (err) {
-    getEvent()?.addWarning(`Webhook subscribe failed for user ${userId}: ${err}`);
+    getEvent()?.addWarning(
+      `Webhook subscribe failed for user ${userId}: ${err}`,
+    );
   }
 }