API & OpenAPI utility
HTTP Header Builder
Validate and normalize an HTTP header block for a request.
● This tool runs entirely in your browser. Your input is never uploaded to our servers.
Output
Your result will appear here…
How to use HTTP Header Builder
- Enter one header per line using Name: value.
- Select Build Headers to validate and normalize the lines.
- Keep authorization values private and avoid storing them in shell history.
Example
Input:
Content-Type: application/json Accept: application/json
Output:
Content-Type: application/json Accept: application/json
Use cases
- Prepare headers for an API request.
- Check header name and value formatting.
- Create a clean header block for curl or documentation.
About this tool
Validate and normalize an HTTP header block for a request. Processing happens locally in your browser, so your input is not sent to a server or included in analytics.
Frequently asked questions
Can I enter Authorization headers?
Yes, but the value remains visible in the output and should be treated as a secret.
Are duplicate headers allowed?
Yes. Multiple lines with the same header name are preserved.
Are headers transmitted?
No. This tool only formats text in your browser.