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Ajax

AJAX “CORS Works in Postman But Fails in Browser” — Preflight Hell

- 12.12.25 - ErcanOPAK

99% of devs forget this:

Preflight requires BOTH headers:

Access-Control-Allow-Origin: *
Access-Control-Allow-Headers: *

✔ Fix server side

Add:

Access-Control-Allow-Methods: GET,POST,PUT,DELETE

💡 Why Postman Works

Postman does NOT run preflight.
Browser does.

Related posts:

AJAX “POST Works Locally but Not in Production” — HTTPS Mixed Content

AJAX Cache Nightmare — Why Your GET Requests Don’t Update

Ajax Calls Fail Only Behind Load Balancer

Post Views: 4

Post navigation

JS “Object Mutation Side Effects” — The Hidden Reference Bug
Windows 11 “CPU Stays High for No Reason” — SearchIndexer Loop Bug

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