🚀 HTTP/2 Checker - Test HTTP/2 Protocol Support

🚀 HTTP/2 Protocol Check

Enter a complete URL (including https://)

⚡ Quick Tests

📚 Protocol Versions

HTTP/1.0: Legacy (1996)
HTTP/1.1: Standard (1997)
HTTP/2: Modern (2015)
HTTP/3: Future (2022)

📊 Test Results

{{ results.length }} site(s) tested
No tests run yet. Enter a URL and click "Check HTTP/2" to begin.
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{{ result.url }}
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Protocol Analysis:
Protocol: {{ result.protocolInfo.version }}
TLS: {{ result.protocolInfo.tls ? 'Yes' : 'No' }}
ALPN: {{ result.protocolInfo.alpn || 'N/A' }}
Response Time: {{ result.protocolInfo.responseTime }}ms
HTTP/2 Features:
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Server Information:
Server: {{ result.serverInfo.server }}
Via: {{ result.serverInfo.via }}
CDN: {{ result.serverInfo.cdn }}
Error:

🌐 Browser Support

Chrome 40+ ✅ Full Support
Firefox 36+ ✅ Full Support
Safari 9+ ✅ Full Support
Edge 12+ ✅ Full Support
Internet Explorer ❌ Not Supported

💡 Implementation Tips

✅ Enable HTTP/2
Nginx: http2 on; Apache: Protocols h2 h2c http/1.1
🔒 Require HTTPS
Most browsers only support HTTP/2 over TLS
⚡ Optimize Resources
Reduce concatenation, enable server push
⚠️

ℹ️ About HTTP/2 Checker

What This HTTP/2 Checker Tests

This HTTP/2 checker tests whether a website negotiates the h2 protocol for a live URL. HTTP/2 keeps the same HTTP request and response semantics as modern HTTP, but sends them over a binary framing layer with multiplexed streams and compressed headers. It is useful for checking CDN configuration, reverse proxies, load balancers, web server upgrades, and redirects that may silently fall back to HTTP/1.1.

What HTTP/2 Support Means

Protocol signals

  • ALPN result: HTTPS sites usually advertise h2 through TLS Application-Layer Protocol Negotiation.
  • Binary framing: Requests and responses are split into frames and streams instead of plain HTTP/1.1 text messages.
  • Multiplexing: Several requests can share one connection without waiting for each response in order.
  • HPACK: Repeated headers are compressed to reduce cookie, cache, and metadata overhead.

Common checks

  • Confirm that https://example.com negotiates h2 instead of http/1.1.
  • Compare apex, www, and redirected URLs after a CDN or web server change.
  • Verify that a reverse proxy still offers HTTP/2 after TLS certificate or cipher changes.
  • Spot legacy SPDY references; SPDY is obsolete and should not be treated as HTTP/2 support.

HTTP/2 vs HTTP/1.1 Results

When the checker reports HTTP/2

  • The tested endpoint negotiated h2 for this connection.
  • Multiplexed streams and HPACK header compression are available for compatible clients.
  • The result does not prove the whole site is faster; performance still depends on caching, asset layout, priorities, and origin latency.

When the checker reports HTTP/1.1

  • The endpoint did not negotiate h2 from this test environment.
  • Possible causes include disabled HTTP/2 on the server, CDN rules, TLS or ALPN misconfiguration, or a redirect to a different host.
  • Cleartext HTTP/2 (h2c) exists, but public browser-facing HTTP/2 is normally tested over HTTPS.

Specifications and Edge Cases

The current HTTP/2 specification is RFC 9113. HTTP semantics are defined separately in RFC 9110, HPACK header compression is defined in RFC 7541, and TLS ALPN is defined in RFC 7301.

Limitations

  • Results can vary by region, IPv4 vs IPv6 path, CDN edge, SNI hostname, and whether redirects are followed.
  • This tool checks protocol negotiation, not TLS certificate quality, HTTP security headers, Core Web Vitals, or HTTP/3 support.
  • Server Push is part of the HTTP/2 history, but many modern deployments disable it; lack of useful push behavior does not mean HTTP/2 is unavailable.
  • Testing an internal or firewalled hostname may fail from the public server even when it works on your local network.
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