Pasting only the response body
Header analysis needs the status line and header block, not just HTML or JSON content. Copy the response headers from DevTools or curl.
HTTP Header Parser | Inspect Request & Response Headers
EncodingRuns in Your Browser (No Uploads)
Parse raw HTTP request or response headers into a normalized, readable summary with duplicate detection and cache, security, CORS, and content header groups.
What to do next
Continue with a related workflow or open the next tool that usually follows this task.
Workflow guide
Format JSON for API debugging
Use this workflow when an API response is hard to read, a JSON payload fails validation, or a frontend error points to malformed structured data.
OpenRelated toolBase64 Encoder and Decoder Online | UTF-8 and URL-Safe Text
Encode or decode Base64 text with UTF-8 support and local-only processing.
OpenRelated toolHash Generator Online | MD5, SHA-256 and SHA-512 Checksums
Generate MD5, SHA-1, SHA-256, and SHA-512 checksums locally.
OpenRelated toolJSON Formatter and Validator Online | Format, Minify, Debug
Format, validate, and minify JSON with instant error highlights—fully local.
OpenHow to Use This Tool
Paste raw HTTP request or response headers into the input.
Review the normalized header list and skipped-line warnings.
Check duplicate header names such as Accept or Set-Cookie.
Use the grouped summary to inspect cache, security, CORS, and content headers.
Copy or download the normalized output for debugging notes.
When to Use This Tool
Cache Debugging
Inspect cache-control, etag, expires, vary, and age headers before debugging stale API or CDN responses.
CORS Troubleshooting
Check CORS response headers before testing a frontend request that fails in the browser.
Security Header Review
Review HSTS, CSP, frame, content-type, and referrer-related headers while preparing deployment checks.
API Debugging Notes
Normalize copied request headers from DevTools or curl when documenting API issues.
Common Mistakes
Ignoring duplicate headers
Set-Cookie and cache-related headers can appear more than once. Check duplicates before deciding whether a server or proxy is misconfigured.
Mixing request and response headers
Request headers describe what the browser sent; response headers describe what the server returned. Keep them separate when debugging caching, CORS, or security issues.
Examples
Inspect response headers
Input
HTTP/1.1 200 OK
content-type: application/json
cache-control: public, max-age=3600
strict-transport-security: max-age=31536000; includeSubDomainsOutput
Start line: HTTP/1.1 200 OK
Total headers: 3
Cache headers: cache-control
Security headers: strict-transport-securityFind duplicate request headers
Input
GET /api/users HTTP/1.1
Host: api.example.com
Accept: application/json
Accept: text/plainOutput
Start line: GET /api/users HTTP/1.1
Duplicate header names: 1
Normalized headers:
host: api.example.com
accept: application/json
accept: text/plainHow HTTP Header Parsing Works
The parser recognizes HTTP request and response start lines before reading name/value header pairs.
Header names are grouped case-insensitively while original values are preserved.
Repeated header names are reported as duplicates instead of being overwritten.
Continuation lines are folded into the previous header value for readable output.
Malformed lines are skipped with warnings so a partial log still produces useful results.
Frequently Asked Questions
Can I paste a full response header block?
Yes. Paste the status line and header block from DevTools, curl, a CDN log, or an API client. The parser keeps the start line and normalizes the headers below it.
Are my headers sent to a server?
No. Everything runs locally in your browser. The tool does not fetch URLs, upload headers, or store inspected values.
Does this check security headers?
It highlights common cache, CORS, content, request, response, and security header groups. These are inspection hints, not a complete security audit.
Related workflow guides
Use these focused guides when you need a practical workflow before opening the tool.
Workflow guide
Format JSON for API debugging
Use this workflow when an API response is hard to read, a JSON payload fails validation, or a frontend error points to malformed structured data.
Workflow guideInspect HTTP response headers before debugging APIs
Use this workflow when a browser request, API response, redirect, or CDN cache behaves differently than expected and you need a clean header-level view first.
Related Tools
Explore more developer tools
Base64 Encoder and Decoder Online | UTF-8 and URL-Safe Text
Encode or decode Base64 text with UTF-8 support and local-only processing.
Encoding
Hash Generator Online | MD5, SHA-256 and SHA-512 Checksums
Generate MD5, SHA-1, SHA-256, and SHA-512 checksums locally.
Encoding
JSON Formatter and Validator Online | Format, Minify, Debug
Format, validate, and minify JSON with instant error highlights—fully local.
Formatting
JWT Decoder Online | Decode Claims, Header and Expiration
Decode JWT header, payload, claims, and expiration locally.
Security
URL Encoder and Decoder Online | Query String Percent Encoding
Encode or decode query strings, redirects, and URL components locally.
Encoding