diff --git a/README.md b/README.md
index 9c4364e..c739ddc 100644
--- a/README.md
+++ b/README.md
@@ -2168,6 +2168,16 @@ the log level and turns the banner on, and that is all it may ever do: it feeds
 constant directly, so no runtime toggle in a release build can reach the
 hardcoded test phrase.
 
+At the raised log level the console also shows the wallet's addresses with their
+balances and ENS names, the token contracts looked up, and a line for each
+request made through `debugFetch` in `src/shared/log.js` (the explorer, the
+price feed, the RPC calls a site makes, and the endpoint checks in settings) and
+for its response. A request is logged by its HTTP method, the origin of its URL
+(scheme, host and port) and, for a JSON-RPC call, the method name; the balance
+refresh and token lookup name the RPC endpoint by its origin too. The URL's path
+and query string, where RPC providers put API keys, and the request body are
+never logged.
+
 ### Key Decisions
 
 - **No framework**: The popup UI is vanilla JS and HTML. The extension is small
diff --git a/TODO.md b/TODO.md
index ab2810c..7ab64fa 100644
--- a/TODO.md
+++ b/TODO.md
@@ -45,6 +45,14 @@ but the review is broader than any of them.
 
 # Completed Steps
 
+- 2026-10-04: Debug mode no longer writes RPC API keys to the console
+  ([#410](https://git.eeqj.de/sneak/AutistMask/issues/410)). `debugFetch` logged
+  every request's full URL and body, so an RPC endpoint with a key in its path
+  or query string printed that key on every request. It now logs the HTTP
+  method, the URL's origin and, for a JSON-RPC call, the method name. The
+  balance refresh and token lookup log the RPC endpoint by its origin too. The
+  README's DEBUG Mode Policy says what debug mode logs.
+
 - 2026-10-04: A site has at most one connection prompt and one signature prompt
   open at a time ([#405](https://git.eeqj.de/sneak/AutistMask/issues/405)). Each
   `eth_requestAccounts` or `personal_sign` call opened another approval window,
diff --git a/src/shared/balances.js b/src/shared/balances.js
index fcff065..6e83741 100644
--- a/src/shared/balances.js
+++ b/src/shared/balances.js
@@ -10,7 +10,7 @@ const {
 } = require("ethers");
 const { ERC20_ABI } = require("./constants");
 const { NETWORKS } = require("./networks");
-const { log, debugFetch } = require("./log");
+const { log, debugFetch, urlOrigin } = require("./log");
 const { deriveAddressFromXpub } = require("./wallet");
 const { TOKEN_BY_ADDRESS } = require("./tokenList");
 const { LOW_HOLDER_THRESHOLD, parseHoldersCount } = require("./holders");
@@ -203,7 +203,7 @@ async function refreshBalances(
     trackedTokens,
     networkId,
 ) {
-    log.debugf("refreshBalances start, rpc:", rpcUrl);
+    log.debugf("refreshBalances start, rpc:", urlOrigin(rpcUrl));
     const provider = getProvider(rpcUrl, networkId);
     const updates = [];
 
@@ -280,7 +280,7 @@ async function refreshBalances(
 // Look up token metadata from its contract.
 // Calls symbol() and decimals() to verify it implements ERC-20.
 async function lookupTokenInfo(contractAddress, rpcUrl, networkId) {
-    log.debugf("lookupTokenInfo", contractAddress, "rpc:", rpcUrl);
+    log.debugf("lookupTokenInfo", contractAddress, "rpc:", urlOrigin(rpcUrl));
     const provider = getProvider(rpcUrl, networkId);
     const contract = new Contract(contractAddress, ERC20_ABI, provider);
 
diff --git a/src/shared/log.js b/src/shared/log.js
index 551fb20..15c2a1c 100644
--- a/src/shared/log.js
+++ b/src/shared/log.js
@@ -42,14 +42,33 @@ const log = {
     },
 };
 
-// Fetch wrapper that debug-logs every request and response.
+// The origin (scheme, host and port) of a URL, for logging in place of the
+// URL: RPC providers put API keys in the path or the query string. A URL that
+// does not parse gives "", so logging never stops a request.
+function urlOrigin(url) {
+    try {
+        return new URL(url).origin;
+    } catch {
+        return "";
+    }
+}
+
+// Fetch wrapper that debug-logs every request and response. It logs the
+// URL's origin and, for a JSON-RPC body, the method name: never the full URL
+// or body, which can carry an API key or a signed transaction.
 async function debugFetch(url, opts) {
     const method = (opts && opts.method) || "GET";
-    const body = opts && opts.body;
-    log.debugf("fetch →", method, url, body || "");
+    const origin = urlOrigin(url);
+    let rpcMethod = "";
+    try {
+        rpcMethod = JSON.parse(opts.body).method || "";
+    } catch {
+        // no body, or a body that is not JSON
+    }
+    log.debugf("fetch →", method, origin, rpcMethod);
     const resp = await fetch(url, opts);
-    log.debugf("fetch ←", resp.status, url);
+    log.debugf("fetch ←", resp.status, origin);
     return resp;
 }
 
-module.exports = { log, debugFetch, setRuntimeDebug, isDebug };
+module.exports = { log, debugFetch, urlOrigin, setRuntimeDebug, isDebug };
diff --git a/tests/debugFetch.test.js b/tests/debugFetch.test.js
new file mode 100644
index 0000000..20f5165
--- /dev/null
+++ b/tests/debugFetch.test.js
@@ -0,0 +1,44 @@
+// What debugFetch writes to the console in debug mode.
+//
+// RPC providers put the API key in the URL's path or query string, and the
+// debug log used to print the whole URL and request body, so turning debug
+// mode on wrote the key to the console
+// (https://git.eeqj.de/sneak/AutistMask/issues/410). The log now names the
+// HTTP method, the URL's origin and the JSON-RPC method, and nothing else of
+// the request.
+
+const { debugFetch, setRuntimeDebug } = require("../src/shared/log");
+
+const realFetch = globalThis.fetch;
+
+afterEach(() => {
+    globalThis.fetch = realFetch;
+    setRuntimeDebug(false);
+    jest.restoreAllMocks();
+});
+
+test("logs the origin and JSON-RPC method, not the key in the URL", async () => {
+    setRuntimeDebug(true);
+    const consoleLog = jest.spyOn(console, "log").mockImplementation(() => {});
+    globalThis.fetch = jest.fn(async () => ({ status: 200 }));
+
+    await debugFetch(
+        "https://rpc.example.invalid/v3/PATHKEY123?token=QUERYTOKEN456",
+        {
+            method: "POST",
+            headers: { "Content-Type": "application/json" },
+            body: JSON.stringify({
+                jsonrpc: "2.0",
+                id: 1,
+                method: "eth_chainId",
+                params: [],
+            }),
+        },
+    );
+
+    const logged = consoleLog.mock.calls.flat().join(" ");
+    expect(logged).not.toContain("PATHKEY123");
+    expect(logged).not.toContain("QUERYTOKEN456");
+    expect(logged).toContain("https://rpc.example.invalid");
+    expect(logged).toContain("eth_chainId");
+});
diff --git a/tests/sendDisplayFloor.test.js b/tests/sendDisplayFloor.test.js
index c366314..1e0b885 100644
--- a/tests/sendDisplayFloor.test.js
+++ b/tests/sendDisplayFloor.test.js
@@ -66,6 +66,7 @@ jest.mock("../src/shared/log", () => ({
         status: 200,
         json: async () => mockExplorer.items,
     })),
+    urlOrigin: () => "",
     setRuntimeDebug: () => {},
     isDebug: () => false,
 }));
diff --git a/tests/symbolSpoof.test.js b/tests/symbolSpoof.test.js
index 94163be..b0b6090 100644
--- a/tests/symbolSpoof.test.js
+++ b/tests/symbolSpoof.test.js
@@ -44,6 +44,7 @@ jest.mock("../src/shared/log", () => ({
         errorf: () => {},
     },
     debugFetch: jest.fn(),
+    urlOrigin: () => "",
     setRuntimeDebug: () => {},
     isDebug: () => false,
 }));