Parse Headers
This HTTP header viewer is a developer tool that converts raw HTTP header text into structured key-value rows.
How to Use This HTTP Header Viewer
- Paste one header per line in the format
Header-Name: value. - Click Parse to transform raw text into key-value rows.
- Review rows for missing colons, duplicates, or unexpected values.
Inputs and Outputs
| Type | Details |
|---|---|
| Input | Raw HTTP header lines from request or response logs |
| Input format | Header-Name: value per line |
| Output | Readable table with two columns: header name and value |
| Edge behavior | Lines without : are shown as unparsed rows |
Worked Examples
Example 1: Typical response headers
Content-Type: text/html; charset=utf-8
Cache-Control: no-store
X-Frame-Options: DENYResult: three parsed rows with clear header names and values.
Example 2: Edge case with an invalid line
Content-Type: application/json
Invalid Header Line
Authorization: Bearer token123Result: two parsed rows and one unparsed row for Invalid Header Line.
Common Mistakes
- Using spaces instead of a colon between header name and value.
- Pasting request/response start lines and expecting full HTTP message parsing.
- Assuming parsed output means the header policy is valid or secure.
Trust and Limitations
This HTTP header viewer runs in your browser and does not fetch network resources. It only parses text you paste.
It does not validate RFC compliance, simulate browser behavior, or evaluate CORS/cache/security correctness. For related tasks, try the meta tag generator, robots.txt generator, or UTM link builder.
Privacy & Limitations
- All calculations run entirely in your browser -- nothing is sent to any server.
- Results are estimates and may vary based on actual conditions.
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HTTP Header Viewer FAQ
What is an HTTP header viewer?
An HTTP header viewer is a tool that parses raw request or response headers and shows each header name with its value in a readable format.
What input format does this HTTP header viewer expect?
Use one header per line in the format Header-Name: value. Empty lines are ignored. Lines without a colon are displayed as unparsed rows.
Can this tool parse both request and response headers?
Yes. It parses any raw HTTP header lines you paste, regardless of whether they came from an HTTP request or an HTTP response.
Does this HTTP header viewer make network requests?
No. Parsing runs fully in your browser. The tool does not fetch URLs or send your pasted headers to a server.
How are duplicate headers handled?
Duplicate header names are shown as separate rows in the order you paste them so you can inspect repeated values such as Set-Cookie.
Will this validate whether a header is semantically correct?
No. The tool parses formatting only. It does not verify RFC-level correctness, cache behavior, CORS policy, or security outcomes.
Why did a line show as unparsed?
A line is shown as unparsed when it does not contain a colon separator. Add a colon between the header name and value to parse it as a key-value pair.
Is this tool suitable for sensitive data?
It is safer than server-side tools because it runs locally in the browser, but you should still avoid sharing pasted screenshots or logs that contain credentials.