Why are multiple Set-Cookie headers preserved?

Servers frequently send multiple Set-Cookie headers to set different cookies with distinct attributes. Standard JSON objects cannot hold duplicate keys, so this parser groups them into an array.

What is obsolete line folding in HTTP headers?

In older HTTP/1.1 specifications (RFC 2616), headers could span multiple lines if continuation lines began with whitespace. This parser safely unwraps folded headers in compliance with RFC 7230.

Which HTTP security headers are most critical for web applications?

The most critical security headers are Content-Security-Policy (defends against XSS), Strict-Transport-Security (forces HTTPS), X-Frame-Options (prevents clickjacking), X-Content-Type-Options (blocks MIME confusion), and Referrer-Policy (protects user privacy).

How do Cache-Control headers impact API and website performance?

Cache-Control directives like max-age, must-revalidate, and stale-while-revalidate dictate how CDNs and browsers store responses. Misconfigured headers can cause users to see outdated data or overload origin servers.

How does CORS (Cross-Origin Resource Sharing) work in HTTP headers?

CORS uses headers such as Access-Control-Allow-Origin, Access-Control-Allow-Methods, and Access-Control-Allow-Headers to tell browsers whether client-side JavaScript on one domain is permitted to read API data from another domain.

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HTTP Headers Parser

Parse raw HTTP request and response headers into structured key-value data and inspect common security, caching and CORS headers directly in your browser.

Privacy Guarantee: Headers are parsed 100% locally in your browser memory. Authentication tokens, session cookies, and private server paths are never sent to any server.

Local Browser Inspection: Raw HTTP headers are parsed locally in memory. Session cookies, authorization tokens, and server signatures are never stored or transmitted to external servers.

Raw HTTP Headers Input

Samples:

HTTP Response Status

200OK

Security Headers Inspection

6 of 7 detected

Strict-Transport-SecurityDetected

max-age=31536000; includeSubDomains; preload

Enforces HTTPS encrypted connections and protects against SSL-stripping man-in-the-middle attacks.

Content-Security-PolicyDetected

default-src 'self'; script-src 'self' 'unsafe-inline'; object-src 'none'

Restricts the resources (scripts, images, stylesheets) that the browser is allowed to load.

X-Content-Type-OptionsDetected

nosniff

Instructs browsers not to sniff MIME types away from the declared Content-Type.

Referrer-PolicyDetected

strict-origin-when-cross-origin

Controls how much referrer information (URL parameters/origin) is sent along with outbound requests.

Permissions-PolicyDetected

camera=(), microphone=(), geolocation=()

Controls which browser features and APIs (camera, microphone, geolocation) can be activated in the document.

Cross-Origin-Opener-PolicyDetected

same-origin

Ensures top-level document does not share a browsing context group with cross-origin documents.

Cross-Origin-Resource-PolicyNot detected

Blocks cross-origin reads of the given resource by other origins.

Caching Directives

Cache-ControlConfigured

public, max-age=3600, stale-while-revalidate=86400

ETagConfigured

W/"4f-7b5c39a0"

ExpiresNone

AgeNone

Last-ModifiedNone

VaryConfigured

Accept-Encoding

Cross-Origin (CORS) Policy

Access-Control-Allow-OriginConfigured

Access-Control-Allow-MethodsConfigured

GET, POST, OPTIONS

Access-Control-Allow-HeadersConfigured

Content-Type, Authorization

Access-Control-Allow-CredentialsNone

How to Use

Paste raw HTTP response or request headers from browser DevTools, server logs, or cURL -i terminal output.

Navigate between Parsed Cards, Searchable Table, and Clean JSON view tabs.

Check the automated Security Headers Audit panel to evaluate HSTS, CSP, X-Frame-Options, and Referrer-Policy posture.

Inspect Caching and Cache-Control directives (max-age, no-cache, stale-while-revalidate, ETag).

Examine duplicate headers like Set-Cookie grouped cleanly without data loss.

Copy normalized JSON representation or individual header values to clipboard with one click.

Why Use HTTP Headers Parser?

Structured Multi-View Inspector

Explore headers through an interactive card overview, searchable table, or formatted JSON output.

Security & Caching Auditing

Instantly identifies HSTS, CSP, Referrer-Policy, Cache-Control, ETag, and CORS directives.

Preserves Duplicate Headers

Correctly preserves multiple headers with identical keys (such as Set-Cookie) rather than silently overwriting them.

Request & Response Support

Parses both HTTP response status lines and HTTP request method lines with obsolete line-folding support.

About This Tool

The HTTP Headers Parser inspects raw HTTP request and response header dumps from network captures, server logs, or cURL output. It parses status lines, preserves duplicate headers such as Set-Cookie, provides categorized views, and highlights security, caching, and CORS header configurations.

Tags:#HTTP headers parser#HTTP header parser#raw HTTP headers parser#HTTP headers to JSON#HTTP response headers parser#HTTP request headers parser

Frequently Asked Questions

No. This tool is a static passive parser that organizes pasted header text. It checks whether common headers are detected or not without making network requests.

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