Fastapi

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: ...

If you build APIs with FastAPI, you’re going to touch CORS almost immediately. Usually right after your frontend starts throwing blocked by CORS policy in DevTools and everyone suddenly becomes a browser networking expert. FastAPI makes CORS easy enough to turn on, but the hard part is choosing the right setup. There’s a big difference between “make the error go away” and “configure cross-origin access without creating a mess.” Here’s the practical comparison guide I wish more teams used. ...