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Parse raw HTTP headers into readable name-value pairs. Use when debugging responses; for URL parts use url-parser. Input: header text ≤10MB. Returns table of headers. 100% client-side.
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Parses HTTP request and response headers with automatic categorization into request, response, entity, and general headers. Includes a security audit that flags missing security headers (like CSP, HSTS, X-Frame-Options), a header builder for constructing custom headers, and cURL/Fetch export of the header configuration. Validates header syntax against RFC standards.
Debugging HTTP headers manually is tedious and security issues like missing CSP or HSTS headers are easy to overlook. This tool centralizes header inspection, security auditing, and code generation in one place to streamline web development and security analysis.
This tool is part of the DevStackIO platform — a collection of free online developer tools from DevStackIO. Browse more free developer resources on DevStackIO.
Web developers debugging API responses, security engineers auditing HTTP security headers, and QA engineers testing server configurations.
Paste raw HTTP headers (from browser dev tools, cURL -v output, or server logs) into the input area
View the categorized output: each header is grouped as request, response, entity, or general
Click the Security Audit button to scan for missing security headers; results highlight what is absent and provide recommendations
Use the Header Builder tab to construct headers manually with key-value pair inputs
Export the header set as a cURL command or a Fetch API JavaScript snippet
Header validation is automatic; invalid headers are flagged with an explanation of the RFC violation
Input: 'Content-Type: text/html\nX-Frame-Options: DENY\nStrict-Transport-Security: max-age=31536000' categorized as entity/response/response with security audit showing HSTS present, CSP missing.Input: 'Content-Type: application/json' built in Header Builder, exported as Fetch: 'fetch(url, {headers: {"Content-Type": "application/json"}})'What security headers does the audit check?
It checks CSP, HSTS, X-Frame-Options, X-Content-Type-Options, Referrer-Policy, Permissions-Policy, and more.
Can I parse headers from a HAR file?
Yes, extract the headers section from the HAR JSON and paste them.
Does it support HTTP/2 pseudo-headers?
Yes, :method, :path, :scheme, :authority are parsed correctly.
Can I export as Python requests code?
Currently supports cURL and Fetch export; Python coming soon.
Authoritative specifications, standards, and in-depth reading for HTTP Header Parser.
Look up HTTP status code meanings and fixes. Use as quick reference; for header debug use http-header-parser. Input: code or search. Returns description. 100% client-side.
Split any URL into protocol, host, path, and query params. Use when inspecting URLs; for encoding query strings use url-encoder. Input: URL text. Returns component table. 100% client-side.
Parse user-agent strings into browser, OS, and device. Use when debugging traffic; for live device data use device-information. Input: UA string. Returns parsed fields. 100% client-side.
Calculate network, broadcast, and host range from CIDR. Use for subnet math; for geo lookup use ip-lookup. Input: IP/CIDR. Returns network details. 100% client-side.
Look up DNS records for any domain. Use when checking DNS; for IP geo use ip-lookup. Input: domain name. Returns A, MX, TXT records. 100% client-side.
Look up geolocation and ISP for any IP address. Use for geo data; for subnet math use ip-calculator. Input: IPv4/IPv6. Returns location and ASN. 100% client-side.
Generate Basic Auth headers from username and password. Use when testing APIs; for JWTs use jwt-generator. Input: credentials text. Returns Authorization header. 100% client-side.
Calculate IPv4 subnets, masks, and host counts. Use for IPv4 planning; for IPv6 use ipv6-calculator. Input: CIDR or mask. Returns subnet table. 100% client-side.
Learn the concepts behind this tool.
HTTP
Hypertext Transfer Protocol is the request-response protocol of the web defined by RFC 9110. A client sends a method and headers, and the server returns a status and body.
View in glossary →CORS
Cross-Origin Resource Sharing is a browser security mechanism that controls cross-origin requests via HTTP headers. Servers must explicitly allow origins, methods, and headers.
View in glossary →API
Application Programming Interface is a contract that defines how software components interact through endpoints, parameters, and data formats. It enables reuse and integration.
View in glossary →REST
Representational State Transfer is an architectural style for APIs using stateless HTTP methods and resource URLs. RESTful services use standard verbs and status codes predictably.
View in glossary →WebSocket
WebSocket is a protocol that upgrades an HTTP connection to a persistent, bidirectional channel per RFC 6455. It enables real-time messaging without repeated polling overhead.
View in glossary →