diff --git a/telemetry-worker/README.md b/telemetry-worker/README.md
index b5e48032..49ea4d66 100644
--- a/telemetry-worker/README.md
+++ b/telemetry-worker/README.md
@@ -1249,6 +1249,22 @@ One new table, `suggest_usage`. Additive; apply it before or after the deploy:
 `npx --yes wrangler@4 d1 migrations apply genclass-dashboard --remote`. Then set the key, as a secret, from your own
 terminal: `npx --yes wrangler@4 secret put OPENAI_API_KEY`.
 
+## Extra keys (two apps merged into one)
+
+When an onboarding left one person with two apps for one site (one with the data, one with the plan), they are merged
+into one app and the key of the app that goes away keeps working: `app_keys` (migration 0022) maps that key to the
+remaining app's own key, and a batch that carries it is aggregated, exported and forwarded under the app's key
+(`src/dashboard.ts` `canonicalToken`; the raw batch in R2 keeps the key the page sent). An app's own key always wins;
+deleting the app deletes its extra keys. No route writes the table; add a key by hand:
+
+```bash
+CLOUDFLARE_ACCOUNT_ID=144bd5f5270b51dbe7faf46227a154f0 npx --yes wrangler@4 d1 execute genclass-dashboard --remote \
+  --command "INSERT INTO app_keys (token, project_token, created) VALUES ('<old gc_ key>', (SELECT token FROM projects WHERE id = '<app id>'), strftime('%Y-%m-%dT%H:%M:%fZ', 'now'))"
+```
+
+A worker keeps a key's answer in memory for up to 5 minutes (30 seconds for an unknown key), so a new extra key counts
+within 30 seconds.
+
 ## Reports by email
 
 A GenClass report about an account's apps goes to the account's email on the schedule it chooses, and an alert goes
diff --git a/telemetry-worker/migrations/0022_app_keys.sql b/telemetry-worker/migrations/0022_app_keys.sql
new file mode 100644
index 00000000..019e6811
--- /dev/null
+++ b/telemetry-worker/migrations/0022_app_keys.sql
@@ -0,0 +1,11 @@
+-- An app's extra keys (owner request, 2026-11-13): when two apps of one account are merged into one (an onboarding that
+-- made two), the key of the app that goes away keeps reporting, counted as the remaining app's own key. A batch that
+-- carries an extra key is aggregated, indexed for export and forwarded under the app's own key (src/collector.ts,
+-- src/dashboard.ts canonicalToken); the raw batch in R2 keeps the key the page sent. Deleting the app deletes its
+-- extra keys. Added by hand for now (telemetry-worker/README.md "Extra keys"): no route writes this table.
+CREATE TABLE IF NOT EXISTS app_keys (
+  token         TEXT PRIMARY KEY,  -- the extra key a page may send (gc_ + 22 base62)
+  project_token TEXT NOT NULL,     -- the app's own key (projects.token)
+  created       TEXT NOT NULL
+) WITHOUT ROWID;
+CREATE INDEX IF NOT EXISTS app_keys_project ON app_keys (project_token);
diff --git a/telemetry-worker/src/auth.ts b/telemetry-worker/src/auth.ts
index 2a30eece..a6ed82ae 100644
--- a/telemetry-worker/src/auth.ts
+++ b/telemetry-worker/src/auth.ts
@@ -1715,6 +1715,8 @@ async function deleteProject(c: C, id: string): Promise<Response> {
     ...["daily", "hourly", "recent", "sessions", "visits", "agent_reports", "agent_log"].map((t) => c.db.prepare(`DELETE FROM ${t} WHERE token = ?`).bind(p.token)),
     c.db.prepare("DELETE FROM projects WHERE id = ? AND account_id = ?").bind(id, a.account.id),
   ]);
+  // its extra keys (migration 0022) go with it; before that migration the table is missing and there is nothing to delete
+  await c.db.prepare("DELETE FROM app_keys WHERE project_token = ?").bind(p.token).run().catch(() => undefined);
   forgetToken(p.token);
   await forgetExports(c.db, c.env.BUCKET, [p.token]).catch(() => undefined);
   // a repository linked to it by the GitHub App is unlinked (on its own: its tables come with migration 0013)
diff --git a/telemetry-worker/src/collector.ts b/telemetry-worker/src/collector.ts
index 886fb4f6..de654483 100644
--- a/telemetry-worker/src/collector.ts
+++ b/telemetry-worker/src/collector.ts
@@ -13,7 +13,8 @@
 // Per-app tokens and dashboards (src/dashboard.ts, src/pages.ts; also routed on genclass.dev/{api/*,start*,dashboard*}):
 // POST /api/projects, GET /api/projects/<secret>, POST and GET /start, GET /start/<secret>, GET /start/open-source (no account; no token to paste, init makes one unless the quiet choice is ticked), GET
 // /dashboard/<secret>. A batch with a known top-level `token` is also aggregated into D1 for that app's dashboard;
-// without one it is stored in R2 only, exactly as before.
+// without one it is stored in R2 only, exactly as before. A token that is one of an app's extra keys (app_keys,
+// migration 0022: the key of an app merged into it) is counted under that app's own key (dashboard.ts canonicalToken).
 // Every plan includes the dashboard (billing/plans.json), so a private link opens it, also for an app with no account
 // (Free). A plan file that left the dashboard out would open the locked page instead (src/locked.ts) and its stats
 // would answer 402. Collection never depends on it: every known token is aggregated.
@@ -32,7 +33,7 @@ import {
   agentReport,
   aggregate,
   createProject,
-  knownToken,
+  canonicalToken,
   projectBySecret,
   projectsCreatedSince,
   randomBase62,
@@ -336,12 +337,12 @@ async function ingest(request: Request, env: Env, opts: HandleOptions): Promise<
   // Past its plan's live fixes for the month, the runtime is told to observe only (src/usage.ts): read before this
   // batch is counted (cached a minute), so the batch itself is stored and counted the same either way.
   const db = env.DB;
-  const observe = batch.token && db ? await observeOnly(db, env, batch.token, now).catch(() => false) : false;
+  // the app this batch belongs to, by its own key: an app's extra key (app_keys, migration 0022) counts as that key
+  const token = batch.token && db ? await canonicalToken(db, batch.token, now.getTime()).catch(() => null) : null;
+  const observe = token && db ? await observeOnly(db, env, token, now).catch(() => false) : false;
   // Dashboard aggregation for a known token. Never affects the response (failures are swallowed).
-  if (batch.token && db) {
-    const token = batch.token;
+  if (token && db) {
     const task = (async () => {
-      if (!(await knownToken(db, token, now.getTime()))) return;
       await aggregate(db, token, { ...batch, country }, now).catch(() => undefined);
       // export index, and forwarding for apps on a paid plan (src/paid.ts)
       const f = opts.fetch ?? ((u: string, i?: RequestInit) => fetch(u, i));
diff --git a/telemetry-worker/src/dashboard.ts b/telemetry-worker/src/dashboard.ts
index f3596e7e..35da0fcc 100644
--- a/telemetry-worker/src/dashboard.ts
+++ b/telemetry-worker/src/dashboard.ts
@@ -147,7 +147,7 @@ export async function createProject(
         .prepare("INSERT INTO projects (id, token, secret_hash, name, created, account_id, private_link) VALUES (?, ?, ?, ?, ?, ?, ?)")
         .bind(id, token, await sha256Hex(secret), name, created, accountId, accountId ? 0 : 1)
         .run();
-      tokenCache.set(token, { ok: true, exp: now.getTime() + CACHE_OK_MS });
+      tokenCache.set(token, { token, exp: now.getTime() + CACHE_OK_MS });
       return { id, token, secret, name, created };
     } catch (e) {
       if (attempt >= 2) throw e; // a collision is astronomically unlikely; anything else is a real error
@@ -175,28 +175,47 @@ export async function projectBySecret(db: D1Like, secret: string): Promise<Proje
     .first<Project>();
 }
 
-/** Drop a deleted project's token from this isolate's cache, so its batches stop being counted here at once. */
+/** Drop a deleted project's token from this isolate's cache, and its extra keys, so their batches stop being counted here at once. */
 export function forgetToken(token: string): void {
   tokenCache.delete(token);
+  for (const [k, v] of tokenCache) if (v.token === token) tokenCache.delete(k);
 }
 
 const CACHE_OK_MS = 5 * 60_000;
 const CACHE_MISS_MS = 30_000;
-const tokenCache = new Map<string, { ok: boolean; exp: number }>();
+const tokenCache = new Map<string, { token: string | null; exp: number }>();
 export function resetTokenCache(): void {
   tokenCache.clear();
 }
 
-/** Is this a token of a known project? Cached in memory briefly (5 min hits, 30 s misses). */
-export async function knownToken(db: D1Like, token: string, nowMs: number): Promise<boolean> {
-  if (!TOKEN_RE.test(token)) return false;
+/**
+ * The app a batch's token belongs to, as that app's own key: the token itself when it is an app's key, the app's key
+ * when it is one of that app's extra keys (app_keys, migration 0022), else null. Cached in memory briefly (5 min hits,
+ * 30 s misses). An app's own key always wins over an extra key with the same value.
+ */
+export async function canonicalToken(db: D1Like, token: string, nowMs: number): Promise<string | null> {
+  if (!TOKEN_RE.test(token)) return null;
   const c = tokenCache.get(token);
-  if (c && c.exp > nowMs) return c.ok;
-  const row = await db.prepare("SELECT 1 AS ok FROM projects WHERE token = ?").bind(token).first();
-  const ok = !!row;
+  if (c && c.exp > nowMs) return c.token;
+  const own = await db.prepare("SELECT token FROM projects WHERE token = ?").bind(token).first<{ token: string }>();
+  let found = own?.token ?? null;
+  if (!found) {
+    // before migration 0022 the table is missing: that reads as "no extra key"
+    const extra = await db
+      .prepare("SELECT k.project_token AS token FROM app_keys k JOIN projects p ON p.token = k.project_token WHERE k.token = ?")
+      .bind(token)
+      .first<{ token: string }>()
+      .catch(() => null);
+    found = extra?.token ?? null;
+  }
   if (tokenCache.size > 5000) tokenCache.clear();
-  tokenCache.set(token, { ok, exp: nowMs + (ok ? CACHE_OK_MS : CACHE_MISS_MS) });
-  return ok;
+  tokenCache.set(token, { token: found, exp: nowMs + (found ? CACHE_OK_MS : CACHE_MISS_MS) });
+  return found;
+}
+
+/** Is this a token of a known project (its own key or one of its extra keys)? */
+export async function knownToken(db: D1Like, token: string, nowMs: number): Promise<boolean> {
+  return (await canonicalToken(db, token, nowMs)) !== null;
 }
 
 // --------------------------------------------------------------------------------------------- aggregation
diff --git a/telemetry-worker/test/app-keys.test.ts b/telemetry-worker/test/app-keys.test.ts
new file mode 100644
index 00000000..bf7742b0
--- /dev/null
+++ b/telemetry-worker/test/app-keys.test.ts
@@ -0,0 +1,62 @@
+// An app's extra keys (migration 0022, src/dashboard.ts canonicalToken, src/collector.ts ingest): a batch that carries
+// one is counted on the app it belongs to, as if it carried the app's own key; an unknown key is still not counted; an
+// app's own key wins over an extra key with the same value; deleting the app deletes its extra keys.
+import { beforeEach, describe, expect, it } from "vitest";
+import { canonicalToken, resetTokenCache } from "../src/dashboard.js";
+import { call, createApp, now, resetClock, sendBatch, setup, signedIn } from "./account-helpers.js";
+
+const page = (route: string): Record<string, unknown> => ({ t: "session", seq: 0, at: 0, host: "shop.example", route, effectiveMode: "observe" });
+
+const OLD = "gc_OLDKEYOLDKEYOLDKEYOLDKEY0".slice(0, 25);
+
+const loads = (sql: ReturnType<typeof setup>["sql"], token: string): number =>
+  Number((sql.db.prepare("SELECT COALESCE(SUM(count), 0) AS n FROM daily WHERE token = ? AND metric = 'sessions' AND key = ''").get(token) as { n: number }).n);
+
+beforeEach(() => {
+  resetClock();
+  resetTokenCache();
+});
+
+describe("extra keys of an app (migration 0022)", () => {
+  it("a batch with an app's extra key is counted on that app; an unknown key is not", async () => {
+    const { env, sql } = setup();
+    const { cookie } = await signedIn(env);
+    const app = await createApp(env, cookie, "Glyco site");
+    expect(OLD).toMatch(/^gc_[A-Za-z0-9]{22}$/);
+    sql.db.prepare("INSERT INTO app_keys (token, project_token, created) VALUES (?, ?, ?)").run(OLD, app.token, now().toISOString());
+    await sendBatch(env, app.token, [page("/")], { sid: "aaaaaaaaaaaa" });
+    await sendBatch(env, OLD, [page("/pricing")], { sid: "bbbbbbbbbbbb" });
+    await sendBatch(env, "gc_UNKNOWNUNKNOWNUNKNOWN0".slice(0, 25), [page("/")], { sid: "cccccccccccc" });
+    expect(loads(sql, app.token)).toBe(2);
+    expect(loads(sql, OLD)).toBe(0);
+    expect(await canonicalToken(env.DB!, OLD, now().getTime())).toBe(app.token);
+    // the dashboard shows both pages under the one app
+    const routes = sql.db.prepare("SELECT key FROM daily WHERE token = ? AND metric = 'page_route' ORDER BY key").all(app.token) as { key: string }[];
+    expect(routes.map((r) => r.key)).toEqual(["/", "/pricing"]);
+  });
+
+  it("an app's own key wins over an extra key with the same value, and a key whose app is gone counts nowhere", async () => {
+    const { env, sql } = setup();
+    const { cookie } = await signedIn(env);
+    const a = await createApp(env, cookie, "A");
+    const b = await createApp(env, cookie, "B");
+    sql.db.prepare("INSERT INTO app_keys (token, project_token, created) VALUES (?, ?, ?)").run(b.token, a.token, now().toISOString());
+    expect(await canonicalToken(env.DB!, b.token, now().getTime())).toBe(b.token);
+    resetTokenCache();
+    sql.db.prepare("INSERT INTO app_keys (token, project_token, created) VALUES (?, ?, ?)").run(OLD, "gc_NOSUCHAPPNOSUCHAPPNOSU", now().toISOString());
+    expect(await canonicalToken(env.DB!, OLD, now().getTime())).toBeNull();
+  });
+
+  it("deleting the app deletes its extra keys, and the key stops counting at once", async () => {
+    const { env, sql } = setup();
+    const { cookie } = await signedIn(env);
+    const app = await createApp(env, cookie, "Shop");
+    sql.db.prepare("INSERT INTO app_keys (token, project_token, created) VALUES (?, ?, ?)").run(OLD, app.token, now().toISOString());
+    await sendBatch(env, OLD, [page("/")]);
+    expect(loads(sql, app.token)).toBe(1);
+    const del = await call(env, "DELETE", `/api/account/projects/${app.id}`, { body: { confirm: "delete" }, cookie });
+    expect(del.status).toBe(204);
+    expect(sql.db.prepare("SELECT COUNT(*) AS n FROM app_keys").get()).toEqual({ n: 0 });
+    expect(await canonicalToken(env.DB!, OLD, now().getTime())).toBeNull();
+  });
+});