Mock JSON endpoint returning HTTP 429

Live demo endpoint

Any method, any path. Returns 429 Too Many Requests with Content-Type: application/json. OPTIONS returns 204 with CORS headers.

Call it with curl

curl -i https://demo-json-429.supercrontab.com/

Call it with fetch

const res = await fetch("https://demo-json-429.supercrontab.com/");
console.log(res.status); // 429
const body = await res.json();

What HTTP 429 Too Many Requests means

When you see it

You hit a rate limit. Most APIs send a Retry-After header or X-RateLimit-Reset telling you when to come back.

What a client should do

Wait for Retry-After, or back off exponentially with jitter, then retry. Queue work instead of hammering.

Retry?

Once, after a delay

Sample response body

{"ok":true,"id":42,"items":["alpha","beta","gamma"]}

The default for REST APIs. Parse it with response.json() and check the ok field.

Questions