CORS Mistakes in Retool Apps and How to Fix Them
Retool makes it deceptively easy to wire up APIs fast. That’s great right up until the browser starts yelling about CORS and half the team decides “the API is broken.” Usually, the API is fine. The browser is doing exactly what it should do, and your Retool app is running into the same cross-origin rules as any other frontend. I’ve seen the same mistakes over and over with Retool setups: wrong origin assumptions, broken preflight handling, credentials mixed with wildcards, and APIs that technically work in Postman but fail instantly in the browser. Here’s the stuff that trips people up most often, and how I’d fix it. ...