About this tool
Generate Access-Control-Allow-Origin, methods, headers, and credentials settings for local and staging APIs.
Use with the HTTP Header Parser when debugging preflight failures. For a full walkthrough of SPA CORS mistakes, see the CORS headers guide on the blog.
Nothing you configure here is uploaded — copy the headers into your server config.
How to use
- Enter the allowed Origin (a specific site URL or * for open APIs).
- List the HTTP methods your API should accept (GET, POST, …).
- Copy the generated Access-Control-* response headers.
- Add them to your API gateway, Express middleware, or serverless response.
Example
SPA talking to an API
Input
origin: https://app.example.com methods: GET,POST
Output
Access-Control-Allow-Origin: https://app.example.com Access-Control-Allow-Methods: GET, POST Access-Control-Allow-Headers: Content-Type, Authorization Access-Control-Max-Age: 86400
Limitations
- Generating headers does not enable CORS on your server — you must deploy them.
- Credentials mode cannot safely pair with Access-Control-Allow-Origin: *.
- Preflight edge cases (custom headers, private network access) may need extra directives.
Related guides
1Related tools
2Frequently asked questions
What does the CORS Header Generator do?
Generate CORS response headers for your API. Runs in your browser — no install, no account.
How do I use the CORS Header Generator?
Enter the allowed Origin (a specific site URL or * for open APIs). List the HTTP methods your API should accept (GET, POST, …). Copy the generated Access-Control-* response headers. Add them to your API gateway, Express middleware, or serverless response.
Is the CORS Header Generator free?
Yes. No signup, no usage limits, no paywall.
Does the CORS Header Generator upload my data?
No. Processing happens locally in JavaScript. Your input is not uploaded, stored, or logged.
What are the limitations of the CORS Header Generator?
Generating headers does not enable CORS on your server — you must deploy them. Credentials mode cannot safely pair with Access-Control-Allow-Origin: *. Preflight edge cases (custom headers, private network access) may need extra directives.