diff --git a/apps/web/src/lib/server/metrics/metrics.test.ts b/apps/web/src/lib/server/metrics/metrics.test.ts
index 3fa6005..cfa9cb6 100644
--- a/apps/web/src/lib/server/metrics/metrics.test.ts
+++ b/apps/web/src/lib/server/metrics/metrics.test.ts
@@ -302,6 +302,21 @@ describe('siteMetrics', () => {
 		expect(empty.byDay).toEqual([]);
 	});
 
+	it('never calls fetch with the api object as `this` — workerd rejects that', async () => {
+		const thisValues: unknown[] = [];
+		const api = {
+			accountId: 'acct',
+			token: 'tok',
+			fetch: function (this: unknown) {
+				thisValues.push(this);
+				return Promise.resolve(new Response(JSON.stringify({ data: [] })));
+			} as typeof fetch
+		};
+		await siteMetrics(api, DID, 7);
+		expect(thisValues.length).toBeGreaterThan(0);
+		for (const t of thisValues) expect(t).toBe(globalThis);
+	});
+
 	it('surfaces an API failure with the status', async () => {
 		const api = {
 			accountId: 'acct',
diff --git a/apps/web/src/lib/server/metrics/query.ts b/apps/web/src/lib/server/metrics/query.ts
index 5b022ef..d1b68ff 100644
--- a/apps/web/src/lib/server/metrics/query.ts
+++ b/apps/web/src/lib/server/metrics/query.ts
@@ -49,7 +49,9 @@ export function didLiteral(did: string): string {
 }
 
 async function sql(api: MetricsApi, query: string): Promise<Record<string, unknown>[]> {
-	const res = await api.fetch(
+	// fetch rejects a foreign `this` (the api object a method call would pass).
+	const res = await api.fetch.call(
+		globalThis,
 		`https://api.cloudflare.com/client/v4/accounts/${api.accountId}/analytics_engine/sql`,
 		{
 			method: 'POST',