HTTP Header Builder / Parser
Compose headers or parse raw header blocks in seconds.
Header input
Runs in your browser
Tip: one header per line in "Key: Value" format.
Output
Privacy note: processing happens locally in your browser.
What this tool does
Build headers from key-value pairs or parse raw header blocks into structured data.
When to use it
Use it when debugging API calls, caching, or content negotiation.
Best practices
Use proper casing, avoid duplicate headers unless allowed, and validate values.
How to build or parse headers
Add key-value pairs or paste raw headers.
- Enter header pairs or paste raw headers.
- Click Build or Parse.
- Copy the output.
FAQ
Does this tool upload headers?
No. Everything runs locally in your browser.
Can I parse response headers?
Yes, paste any raw header block.
Does it normalize casing?
It keeps your input as-is.