Nextjs

CORS on Railway usually breaks for the same boring reasons it breaks everywhere else: wrong origin, missing preflight handling, credentials mixed with *, or a proxy layer eating headers. Railway itself is not the hard part. Your app is. This guide is the version I wish I could paste into every “CORS error on Railway” thread. What Railway changes Railway gives you deployed services on Railway-owned domains and often custom domains on top. That means your frontend and backend commonly end up on different origins: ...

Stripe webhooks and CORS get mixed together constantly, and that usually means someone is solving the wrong problem. I’ve seen this play out the same way more than once: payments work in Stripe Checkout, the webhook endpoint is live, then somebody opens DevTools, sees a failed browser request, and starts adding Access-Control-Allow-Origin: * to the webhook route. A few commits later, webhook signature verification breaks, preflight requests start showing up where they never mattered, and the team is less sure than before what CORS even applies to. ...

tRPC is great right up until your frontend and API live on different origins and the browser starts throwing CORS errors that look unrelated to your code. I’ve seen this happen a lot with tRPC because the transport feels “magic” when everything is same-origin. Then you split your app across app.example.com and api.example.com, or you run Vite on localhost:5173 against a backend on localhost:3000, and suddenly every request is blocked before your resolver runs. ...