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HTTP headers lookup

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Free HTTP Headers Lookup Tool

The HTTP Headers Lookup tool instantly fetches and analyzes server response headers for any URL. It helps you troubleshoot caching, security, redirects, and content delivery for faster, safer pages. Use it when debugging errors, verifying CDN behavior, auditing SEO/headers, or validating deployments across environments.

What is HTTP Headers Lookup?

HTTP Headers Lookup is a diagnostic tool that retrieves and displays the HTTP response headers sent by a web server when a URL is requested. These headers include crucial metadata such as status code, content type, cache rules, security policies, compression, and server/CDN hints. By inspecting headers, you can quickly understand how a page is served and why it behaves a certain way.

On Monkey Type, the HTTP Headers Lookup tool makes header analysis simple: enter a URL, run the lookup, and get a clean report of response headers along with optional request details. This immediate visibility helps developers, SEOs, and site owners solve issues without guesswork or command-line tools.

If you need to validate where a hostname resolves before checking headers, use the DNS Lookup tool to confirm A, AAAA, and CNAME records first.

Why Use HTTP Headers Lookup?

Fix redirect loops and chains: See Location headers and status codes (301, 302, 307, 308) to identify and shorten redirect paths, improving speed and crawl efficiency. When needed, pair with the Redirect Checker.
Optimize caching and performance: Inspect Cache-Control, Expires, ETag, and Vary to tune browser and CDN caching for faster loads and lower bandwidth costs.
Harden security: Verify HSTS, Content-Security-Policy, X-Frame-Options, X-Content-Type-Options, and Referrer-Policy to reduce attack surface and compliance risks.
Debug CORS and APIs: Check Access-Control-Allow-Origin and related CORS headers to resolve cross-origin request issues in web apps and integrations.
Confirm content delivery: Validate Content-Type, encoding (gzip/Brotli), and CDN/server identifiers to ensure correct file types, compression, and edge routing. For certificate trust, cross-check with SSL Checker.

How to Use HTTP Headers Lookup on Monkey Type

Enter the URL: Paste the full URL (including https://). Use the exact path you want to inspect, not just the homepage.
Choose method: Select HEAD for faster header-only checks or GET for full request behavior when debugging complex setups.
Toggle redirects: Decide whether to follow redirects. Disable to view the first hop; enable to see final destination headers. For deeper chains, see the Redirect Checker.
Set user agent (optional): Emulate a bot or device to compare how servers/CDNs vary responses by client.
Run the lookup: Click the button to fetch headers. The tool connects over HTTP(S) and records the response sequence.
Review results: See status code, protocol, and complete response headers. Look for caching, security, CORS, compression, and server/CDN indicators. You may also view request headers for context.
Export or copy: Copy headers for tickets, documentation, or CI logs to share findings with your team.

Expected result: you receive a clear, structured list of server headers for the requested URL, plus status codes for each hop if redirects occur.

Key Features

Fast HEAD/GET checks: Choose the method that matches your debugging needs.
Redirect visibility: Inspect each hop’s status and headers to pinpoint issues quickly.
Security header insights: Verify HSTS, CSP, and other protections at a glance.
CORS diagnostics: Validate Access-Control headers for API and SPA reliability.
Compression and content verification: Confirm Content-Type, charset, gzip, or Brotli usage.
User-Agent controls: Compare how servers respond to bots vs. browsers.
Shareable output: Easily copy results into bug reports or change requests.
Complementary tools: combine with IP Lookup to see server locations and providers.

Best Practices & Tips

Check both www and apex: Compare headers for example.com and www.example.com to ensure consistent redirects and policies.
Audit HTTP and HTTPS: Verify HTTP redirects to HTTPS and confirm HSTS is present on the secure endpoint. Use SSL Checker to validate certificate chains.
Inspect cache rules after deploys: Misconfigured Cache-Control can serve stale assets or bypass CDNs. Recheck after every release.
Test with and without redirects: Many issues hide on the first hop. Disable following redirects to see the source problem.
Emulate real clients: Switch User-Agent to replicate how search engines or mobile devices receive headers.
Document baselines: Keep a record of “known-good” headers so regressions after changes are easy to spot.

Common Use Cases

SEO audits: Validate canonical redirects, indexability headers, and correct content types for crawlers. For domain intel, add a WHOIS Lookup.
Performance tuning: Ensure long-lived caching for static assets and end-to-end compression.
Security hardening: Confirm HSTS, CSP, and MIME sniffing protections are applied consistently.
CDN troubleshooting: Compare origin vs. edge headers to find misconfigurations or cache misses.
API debugging: Resolve CORS failures and content negotiation issues (Accept, Content-Type, Vary).

Frequently Asked Questions

What are HTTP response headers?

HTTP response headers are key–value pairs sent by a server describing the response. They include details like status code, Content-Type, Cache-Control, security policies, and more. They guide browsers, crawlers, and CDNs on how to handle content.

Does HTTP Headers Lookup follow redirects?

Yes, you can choose whether to follow redirects. Disable it to examine the first hop’s headers, or enable it to view the final destination. For mapping entire chains, use the Redirect Checker.

When should I use HEAD vs. GET?

Use HEAD for quick header-only checks when content is not needed. Use GET when server behavior changes based on the full request, authentication, or dynamic routing.