Documentation JavaScript Examples - A/B Testing Configure an A/B test by regulating the type of response based on cookies. Useful for randomized experiments with two variants.A/B testing function handleRequest(request) { const NAME = "TestA/B" const TEST_RESPONSE = new Response("Cookie A") const CONTROL_RESPONSE = new Response("Cookie B") const cookie = request.headers.get("cookie") if (cookie && cookie.includes(`${NAME}=a`)) { return CONTROL_RESPONSE } else if (cookie && cookie.includes(`${NAME}=b`)) { return TEST_RESPONSE } else { const group = Math.random() < 0.5 ? "test" : "control" const response = group === "control" ? CONTROL_RESPONSE : TEST_RESPONSE response.headers.append("Set-Cookie", `${NAME}=${group}; path=/`) return response } } addEventListener("fetch", event => { event.respondWith(handleRequest(event.request)) }) Contributors