# api

## Entries2 knowledge objects

CORS error: No Access-Control-Allow-Origin header on the response
high
The browser blocked the response because the server did not say the requesting origin is allowed. Nothing about the frontend can fix it — the header has to come from the server, and the browser deliberately hides the reason from JavaScript, so the console is the only place the actual rule violation is named.
/k/cors-no-access-control-allow-origin · api · 3 sources · verified 2026-08-07 · CORS ERR_FAILED
Stripe API returns 429 Too Many Requests
high
Stripe returns 429 for two unrelated reasons: you exceeded a rate or concurrency limit, or you hit an object lock timeout. The Stripe-Rate-Limited-Reason header tells you which, and only one of them is fixed by slowing down.
/k/stripe-429-rate-limit · api · 3 sources · verified 2026-08-07 · 429 lock_timeout