Azure

A lot of teams assume Azure Front Door will “handle CORS” because it sits in front of everything. That assumption burns time. I’ve seen this play out the same way more than once: the API works in Postman, works from curl, even works when you hit the backend directly — but the browser says no. Then someone starts adding random Access-Control-* headers at Front Door, somebody else enables caching, and suddenly the failures become intermittent. That’s when the real fun starts. ...

CORS on Azure Functions looks simple until you ship something with auth, multiple environments, and a frontend team that keeps changing origins every sprint. I’ve seen teams treat CORS as a checkbox in the Azure Portal, then spend hours debugging why Authorization headers fail, why local dev works but production doesn’t, or why preflight requests get blocked before their function code even runs. If you’re building browser-facing APIs on Azure Functions, you have a few ways to handle CORS. Some are easy. Some are flexible. Some are traps. ...