Http Header Viewer
What This HTTP Headers Tool Can Do
- Categorizes headers into security, performance, SEO, deprecated and other groups for faster scanning
- Computes simple scores for overall, security, performance and SEO headers to show where you stand at a glance
- Highlights security headers like CSP, HSTS, Referrer-Policy, X-Frame-Options, COOP/COEP/CORP and Origin-Agent-Cluster
- Analyzes Set-Cookie flags to spot missing Secure, HttpOnly or SameSite attributes
- Detects deprecated or risky headers such as X-XSS-Protection, X-Powered-By and Server banners that leak implementation details
- Helps tune performance headers like Cache-Control, Content-Encoding, ETag, Last-Modified and Server-Timing
- Surfaces SEO-related headers like Link (canonical/alternate) and X-Robots-Tag, plus Content-Language when present
- No account, no API key – just paste a public URL, inspect the headers and iterate on your config
🛠️ How to Use the HTTP Headers Viewer for http-headers-viewer
1. Enter the URL
🔗 Paste any valid HTTP or HTTPS URL into the input field. Public endpoints or publicly exposed APIs work best.
2. Fetch the headers
🌐 The backend requests the URL and collects response headers, following redirects when possible. Only headers and basic metadata are inspected – not the full HTML body.
3. Review categories & scores
🧠 Headers are grouped into security, performance, SEO, cookies, deprecated and other buckets. The tool derives scores, issues, warnings and recommendations from your header configuration.
4. Fix and re-test
🔁 Adjust your server, CDN or reverse-proxy configuration, then re-run the check until scores and warnings match your targets. Use it as a quick feedback loop whenever you touch infrastructure.
Technical Details
Request & Response Handling
The tool focuses on response headers and basic connection metadata rather than full page content.
| Aspect | Behavior | Notes |
|---|---|---|
| HTTP method | HEAD or GET (implementation-dependent) | Only headers are inspected; bodies are ignored unless a GET fallback is required. |
| Redirects | Redirect chain recorded when available | Useful to debug 301/302 chains, canonical targets and misconfigured jumps. |
| HTTP version | Captured when provided | Helps identify HTTP/1.1 vs HTTP/2/3 setups and potential upgrade opportunities. |
| Server banner | Read from the Server header | Used to warn about potential information leakage (framework, version). |
| Error handling | Error field surfaced separately | If the fetch fails, you still get a readable error state instead of a crash. |
Header Classification & Analysis
Headers are normalized, then analyzed into typed buckets with dedicated checks and hints.
| Category | Typical Headers | Checks & Insights |
|---|---|---|
| Security | Content-Security-Policy, Strict-Transport-Security, X-Frame-Options, Referrer-Policy, Permissions-Policy, COOP/COEP/CORP, Origin-Agent-Cluster | Validates presence, flags weak or missing directives, detects unsafe CSP patterns and development origins. |
| Performance | Cache-Control, Content-Encoding, ETag, Last-Modified, Accept-Ranges, Link (preload/prefetch), Server-Timing | Checks for caching hints, compression, byte-range support and performance-related Link headers. |
| SEO | Link (canonical/alternate), X-Robots-Tag, Content-Language | Detects canonical/alternate hints and robot directives at header level, plus language metadata where present. |
| Cookies | Set-Cookie | Scans for Secure, HttpOnly, SameSite attributes and warns when flags are missing or look weak. |
| Deprecated | X-XSS-Protection, Public-Key-Pins, legacy CSP variants | Flags headers that should be removed or replaced with modern alternatives. |
Scoring Model
Scores are heuristic, not a full security audit, but they help prioritize work and compare environments.
| Score | What It Measures | How It’s Computed |
|---|---|---|
| Overall score | General header hygiene | Ratio across all weighted headers – mostly presence-based with mild weighting. |
| Security score | Security-related hardening | Weights CSP, HSTS, framing control, Referrer-Policy, Permissions-Policy, COOP/COEP/CORP and Origin-Agent-Cluster. |
| Performance score | Caching & transfer efficiency | Weights Cache-Control, Content-Encoding, ETag, Last-Modified, Accept-Ranges, Server-Timing and performance-related Link usage. |
| SEO score | Header-level SEO signals | Weights X-Robots-Tag, canonical/alternate Link headers and Content-Language when present. |
CLI Alternatives for Header Inspection
Prefer the terminal or integrating header checks into CI/CD? Use these commands as local companions to this tool:
Linux/macOS
View response headers using curl
curl -I https://example.comSends a HEAD request and prints response headers for a quick sanity check.
Verbose output with headers and TLS negotiation
curl -v https://example.comUseful when debugging redirects, TLS configuration and connection details.
Windows (PowerShell)
Fetch and inspect headers with Invoke-WebRequest
(Invoke-WebRequest -Uri https://example.com).HeadersDisplays headers as a PowerShell object, ready for additional filtering or scripting.
Practical Applications
Security Header Review
- Check for missing CSP, HSTS, Referrer-Policy or Permissions-Policy headers on key endpoints.
- Detect unsafe CSP directives such as 'unsafe-inline' without nonces or hashes.
- Spot cookies missing Secure or SameSite attributes and plan fixes for session-hardening.
Performance & Caching Diagnostics
- Inspect Cache-Control, ETag and Content-Encoding configuration across static and dynamic routes.
- Verify presence of performance hints such as preload or preconnect Link headers from your CDN.
- Compare performance-related headers between staging, preview and production environments.
SEO & Redirect Chain Analysis
- Inspect 301/302 redirect chains and confirm the final landing URL is canonical and secure.
- Check canonical and alternate Link headers on HTML pages or localized versions.
- Validate X-Robots-Tag directives for indexing, snippet behavior and media handling.
❓ Frequently Asked Questions
❓What are HTTP response headers and why do they matter?
HTTP response headers are key–value pairs sent by the server before the body. They control caching, security policies, redirects, CORS, cookies and how browsers and crawlers interpret your site. Getting them right is critical for security, performance and SEO.🔒Are the URLs I test stored anywhere?
🧪Can I use this to inspect API responses?
API endpoint is publicly reachable from the server making the request. This is especially useful to inspect CORS headers, rate limiting hints, cache behavior and content types on JSON or XML APIs.🕵️♂️Does it work for pages behind authentication?
📈Is the score a full security audit?
Pro Tips
Compare headers between staging, preview and production to spot missing security hardening or caching rules in one environment.
Treat the Server and X-Powered-By headers as information leaks – remove or minimize them in production whenever possible.
Tune Cache-Control and Content-Encoding first for static assets – they often deliver the biggest performance wins with minimal risk.
Run this tool after each major infrastructure change (CDN, reverse proxy, TLS offload, new host) to confirm headers still look correct.
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