diff --git a/apps/api/src/services/query-service.test.ts b/apps/api/src/services/query-service.test.ts
index 201456e..20acda2 100644
--- a/apps/api/src/services/query-service.test.ts
+++ b/apps/api/src/services/query-service.test.ts
@@ -1,10 +1,33 @@
-import { describe, expect, it } from "vitest";
-import { UnsafeScrapeUrlError } from "../lib/scrape-url-safety.js";
+import { beforeEach, describe, expect, it, vi } from "vitest";
+
+const registryExecuteMock = vi.fn();
+const loggerErrorMock = vi.fn();
+
+vi.mock("../providers/index.js", () => ({
+  registry: {
+    execute: (...args: unknown[]) => registryExecuteMock(...args)
+  }
+}));
+
+vi.mock("../lib/logger.js", () => ({
+  logger: {
+    error: (...args: unknown[]) => loggerErrorMock(...args)
+  }
+}));
 
 describe("executeQuery", () => {
+  beforeEach(() => {
+    registryExecuteMock.mockReset();
+    loggerErrorMock.mockReset();
+    vi.resetModules();
+  });
+
   it("rejects unsafe scrape URLs at the service boundary", async () => {
     process.env.X402_PAY_TO_ADDRESS = "GAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAWHF";
-    const { executeQuery } = await import("./query-service.js");
+    const [{ executeQuery }, { UnsafeScrapeUrlError }] = await Promise.all([
+      import("./query-service.js"),
+      import("../lib/scrape-url-safety.js")
+    ]);
 
     await expect(
       executeQuery({
@@ -14,4 +37,40 @@ describe("executeQuery", () => {
       })
     ).rejects.toBeInstanceOf(UnsafeScrapeUrlError);
   });
+
+  it("logs provider failures with safe metadata only", async () => {
+    process.env.X402_PAY_TO_ADDRESS = "GAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAWHF";
+    const providerError = new Error(
+      'upstream failed query="super secret question" url=https://secret.example.test/search payment-response=proof_123 Authorization:Bearer token_abc privateKey=wallet_secret'
+    );
+    registryExecuteMock.mockRejectedValueOnce(providerError);
+
+    const { executeQuery } = await import("./query-service.js");
+
+    await expect(
+      executeQuery({
+        mode: "search",
+        provider: "search.live",
+        q: "super secret question"
+      })
+    ).rejects.toThrow(providerError.message);
+
+    expect(loggerErrorMock).toHaveBeenCalledTimes(1);
+
+    const [payload, message] = loggerErrorMock.mock.calls[0];
+    const serializedPayload = JSON.stringify(payload);
+
+    expect(message).toBe("provider execution failed");
+    expect(payload).toMatchObject({
+      providerId: "search.live",
+      mode: "search",
+      errorClass: "Error"
+    });
+    expect(payload.errorMessage).toContain("[redacted-url]");
+    expect(serializedPayload).not.toContain("super secret question");
+    expect(serializedPayload).not.toContain("https://secret.example.test/search");
+    expect(serializedPayload).not.toContain("proof_123");
+    expect(serializedPayload).not.toContain("token_abc");
+    expect(serializedPayload).not.toContain("wallet_secret");
+  });
 });
diff --git a/apps/api/src/services/query-service.ts b/apps/api/src/services/query-service.ts
index 43264e1..df24cfc 100644
--- a/apps/api/src/services/query-service.ts
+++ b/apps/api/src/services/query-service.ts
@@ -3,6 +3,37 @@ import { registry } from "../providers/index.js";
 import { nanoid } from "nanoid";
 import { QueryResult } from "@query402/shared";
 import { validateScrapeUrl } from "../lib/scrape-url-safety.js";
+import { logger } from "../lib/logger.js";
+
+function getErrorClass(error: unknown): string {
+  if (error instanceof Error && error.name) {
+    return error.name;
+  }
+
+  return typeof error;
+}
+
+function getErrorMessage(error: unknown): string {
+  if (error instanceof Error) {
+    return error.message;
+  }
+
+  return String(error);
+}
+
+function sanitizeErrorMessage(message: string): string {
+  return message
+    .replace(
+      /\b(url|targetUrl)\b\s*[:=]\s*("[^"]*"|'[^']*'|[^,;]+)/gi,
+      "$1=[redacted-url]"
+    )
+    .replace(/\b(payment-response|x-payment-response|authorization)\b\s*[:=]\s*([^\s,;]+)/gi, "$1=[redacted]")
+    .replace(
+      /\b(query|queryOrUrl|q|secret|api[_ -]?key|token|private[_ -]?key|privateKey|seed)\b\s*[:=]\s*("[^"]*"|'[^']*'|[^,;]+)/gi,
+      "$1=[redacted]"
+    )
+    .replace(/https?:\/\/\S+/gi, "[redacted-url]");
+}
 
 export async function executeQuery(params: {
   mode: "search" | "news" | "scrape";
@@ -24,7 +55,23 @@ export async function executeQuery(params: {
 
   // Registry handles provider matching, circuit breaking, timeouts, and fallbacks
   const start = Date.now();
-  const execution = await registry.execute(params.mode, params.provider, safeInput);
+
+  let execution;
+  try {
+    execution = await registry.execute(params.mode, params.provider, safeInput);
+  } catch (error) {
+    logger.error(
+      {
+        providerId: params.provider,
+        mode: params.mode,
+        errorClass: getErrorClass(error),
+        errorMessage: sanitizeErrorMessage(getErrorMessage(error))
+      },
+      "provider execution failed"
+    );
+    throw error;
+  }
+
   const latencyMs = Date.now() - start;
 
   return {