API Development Ready to use
CORS Preflight Simulator
Enter method, headers, and content type to see if a request preflights and which response headers are needed.
How to use
- 1Open the CORS Preflight Simulator tool page.
- 2Enter or paste your input into the provided fields.
- 3The tool processes your input instantly in your browser.
- 4Copy or download the result using the buttons provided.
Privacy & limitations
- Processing happens locally in your browser — nothing is uploaded.
- Works on modern desktop and mobile browsers.
- Very large inputs may take a moment; the interface will show progress.
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