1. Source
Live TLS ALPN negotiation. The result identifies where its evidence came from.
Free tool, no account required
Free HTTP/2 Test: Live ALPN and TLS Handshake Check
The HTTP/2 Test opens one live TLS connection to the submitted hostname and reads the protocol selected through ALPN. HTTP/2 is confirmed only when the server negotiates h2.
Also known as: HTTP/2 test, ALPN
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Definition
What is an HTTP/2 test?
An HTTP/2 test is a check of whether a server speaks HTTP/2 on a real connection. The Novaverb HTTP/2 Test opens one live HTTPS connection, offers h2 and http/1.1 through TLS ALPN and reports the protocol the endpoint selected, which makes the verdict protocol evidence and not a guessed score or a browser simulation.
Scope
What does the HTTP/2 test check?
The HTTP/2 test checks whether ALPN completed and whether h2 was selected for the submitted hostname. Alongside that verdict it records the selected protocol, the TLS version, the HTTP status code and the timings for TCP connect, TLS plus ALPN and the HTTPS response. The Alt-Svc header is read to note an HTTP/3 advertisement.
Who it is for
Who is the HTTP/2 test for?
The HTTP/2 test is for people who configure or audit how a site is delivered. A developer confirms that enabling h2 on the TLS listener took effect. A site owner behind a CDN checks what visitors negotiate at the public hostname. A technical SEO records the delivery protocol as part of a performance review.
Why it matters
Why use an HTTP/2 test?
An HTTP/2 test catches a site that quietly falls back to HTTP/1.1. A header can claim HTTP/2 while the layer that terminates TLS, often a CDN or reverse proxy, never negotiates it. HTTP/2 multiplexes many requests over one connection, so a missed negotiation leaves resource-heavy pages with the request overhead of HTTP/1.1.
Method
How does the HTTP/2 test work?
The HTTP/2 test works in a short sequence. The input is normalized to the site's origin and a live TLS handshake is completed. The ALPN-negotiated protocol is read, and HTTP/2 is confirmed only when the server actually negotiates h2. The Alt-Svc response header is then read separately to note whether HTTP/3 is advertised.
- We normalize the input to the site's origin and complete a live TLS handshake.
- We read the ALPN-negotiated protocol and confirm HTTP/2 only when the server actually negotiates 'h2' - not from a header that merely claims it.
- We additionally read the Alt-Svc header to note whether HTTP/3 is advertised.
Input
What do you enter into the HTTP/2 test?
Enter a domain or any URL on the site into the HTTP/2 test. Only the origin matters, so the path and query are normalized away before the handshake and the secure origin is tested either way. The exact hostname submitted is the one probed. A search phrase is not an address, and a private host is refused.
Use it like this
yourdomain.comAny address form works. http or https, with or without www, a bare domain or a full path - we normalize it for you. We test the secure origin either way.https://www.yourdomain.com/pageA full URL with a path is fine - HTTP/2 is a connection property, so we check the origin behind it.Avoid this
fast web hostingThat is a search phrase, not an address - enter a domain or URL to test.Result
What does the HTTP/2 test report contain?
The HTTP/2 test report contains a verdict, protocol evidence, a connection timeline and endpoint facts. The verdict reads HTTP/2 is supported or HTTP/2 was not negotiated. Protocol evidence shows h2, ALPN, the selected protocol and the TLS version. The timeline gives timings in milliseconds, and endpoint facts add the status code and the HTTP/3 signal.
Reading it
How do you read an HTTP/2 test result?
Read an HTTP/2 test result from the verdict down. Supported means the TLS handshake selected h2 for this HTTPS endpoint. Not negotiated means the endpoint did not select h2, and a compatible client can fall back to HTTP/1.1. An HTTP/3 signal marked advertised is an Alt-Svc observation only, not a QUIC handshake.
What does an HTTP/2 test measure?
This checker opens one live HTTPS connection, offers h2 and http/1.1 through TLS ALPN, then reports the protocol selected by the endpoint. That makes the verdict protocol evidence - not a guessed score or a browser simulation.
How to enable HTTP/2
- Use HTTPS on the public endpoint: Install a valid certificate and make sure the TLS listener is the edge visitors actually reach.
- Enable h2 on the TLS listener: Configure your web server or CDN to advertise the h2 ALPN identifier; keep HTTP/1.1 as a fallback.
- Retest the edge: A CDN can negotiate HTTP/2 for visitors even when the origin uses a different protocol, so test the public hostname.
If HTTP/2 is not negotiated
Check the certificate and SNI hostname, the CDN or load balancer TLS policy, ALPN support in the TLS stack, and whether a proxy is terminating the connection before it reaches your origin.
What this test proves
The selected ALPN protocol on one fresh TLS connection, plus basic connection timing and the HTTP status.
What it does not prove
It does not guarantee faster pages, HTTP/3 availability, browser support on every network, or good Core Web Vitals.
This test performs a live TLS handshake and reads the ALPN-negotiated protocol; HTTP/3 support is inferred from the Alt-Svc header, not a QUIC handshake.
Source
Where does the HTTP/2 test get its data?
The HTTP/2 test gets its data from live TLS ALPN negotiation: one fresh TLS connection from the measurement service to the submitted hostname. The protocol is read from the handshake itself and not from a header that claims support. A CDN in front of the origin answers the check, as it does for visitors.
Limits
What does the HTTP/2 test not tell you?
The HTTP/2 test does not tell you about protocol support on every edge or network path. One live TLS handshake proves the protocol negotiated by this probe. The result does not measure page speed, subresources or Core Web Vitals, does not cover every CDN location and does not confirm that HTTP/3 works.
Evidence
What does an HTTP/2 test result prove?
An HTTP/2 test result proves the ALPN protocol selected on one fresh TLS connection, plus basic connection timing and the HTTP status. Negotiating h2 shows that a connection is multiplexed, not that a page is fast. When the handshake cannot be completed, the test says so and does not claim that HTTP/2 is absent.
2. Boundary
This performs one live TLS handshake to the submitted hostname. It proves the protocol negotiated by this probe, not protocol support on every edge or network path.
3. Next action
Use the finding to verify a problem, then connect a workspace when you need history, monitoring, or site-wide analysis.
Standards
Which standards does the HTTP/2 test apply?
The HTTP/2 test applies two IETF specifications. RFC 9113 defines HTTP/2 itself. RFC 7301 defines Application-Layer Protocol Negotiation, the TLS extension the test reads to learn which protocol was actually agreed. Reading ALPN and not a response header is what makes the answer a measurement instead of a claim.
IETFRFC 9113
HTTP/2
Confirms HTTP/2 support the way the protocol requires it: via ALPN, not a header claim.
Read the specificationIETFRFC 7301
TLS ALPN Extension
Reads the ALPN-negotiated protocol during the live TLS handshake.
Read the specificationWe list a standard only where this tool genuinely reads or measures against it. Where a signal is outside a live check, the result says so instead of implying coverage.
Verification
How can you verify an HTTP/2 test result yourself?
Verify an HTTP/2 test result in a browser. Open the developer tools, load the page with the network panel open and show the protocol column, where a request served over HTTP/2 is listed as h2. Check the public hostname visitors use, because a CDN can negotiate HTTP/2 while the origin uses a different protocol.
Example
What does a typical HTTP/2 test finding look like?
A typical HTTP/2 test finding reads HTTP/2 is supported, with ALPN negotiated, h2 as the selected protocol, the TLS version shown and the HTTP/3 signal marked advertised. The contrasting finding reads HTTP/2 was not negotiated with http/1.1 as the selected protocol, which points at the CDN, load balancer or proxy that terminates TLS.
Cost
Is the HTTP/2 test free?
The HTTP/2 test is free and runs with no account. Each run is one live handshake for one hostname. An account is needed to go further than a single probe: a workspace tracks HTTP/2, HTTP/3 and TLS support across the whole site over time and keeps each result as saved evidence.
In a workspace
What does a Novaverb workspace add to the HTTP/2 test?
A Novaverb workspace adds a whole-site view and a record over time to the HTTP/2 test. Site Health Audit is the product that continues the job: a source-aware technical checklist that prioritizes supported findings and records fresh rechecks. A protocol finding can be moved into a task and rechecked once the configuration changes.
When to go further
When is a free HTTP/2 test not enough?
A free HTTP/2 test is not enough when a site is served from several hostnames or CDN locations. One probe describes one HTTPS edge at one moment. Each additional hostname needs its own check, a configuration that changes needs recurring measurement, and any question about speed needs field or browser measurements instead.
Next step
What should you do after running the HTTP/2 test?
After running the HTTP/2 test, a not negotiated result leads to a short list of actions. Confirm HTTPS with a valid certificate on the public endpoint. Enable h2 on the TLS listener of the web server or CDN and keep HTTP/1.1 as a fallback. Then retest the public hostname. A supported result needs no change.
Related tools
Which free tools pair with the HTTP/2 test?
The HTTP/2 test pairs with free tools that measure what a protocol check does not. The HTTP/3 Test attempts a real QUIC handshake, which this test only infers from Alt-Svc. The Server Response Time Checker measures Time to First Byte with DNS, TCP and TLS latency. The Core Web Vitals Checker shows real-user LCP, INP and CLS data.
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Questions
What do people ask about the HTTP/2 test?
The HTTP/2 test FAQ answers what HTTP/2 is, how browser and server negotiate it and how to enable it on a site. Other questions compare HTTP/1.1 with HTTP/2, explain why HTTP/2 requires HTTPS in browsers, cover which TLS version a server should use and ask whether HTTP/2 makes a page faster.
What does the Novaverb HTTP/2 Test check?
It performs a live TLS handshake and reads the ALPN-negotiated protocol to confirm whether your server actually serves HTTP/2. It also reports the TLS version and whether HTTP/3 is advertised via the Alt-Svc header.
What is HTTP/2?
HTTP/2 is a major revision of HTTP that multiplexes many requests over a single connection, adds header compression (HPACK), and enables prioritization. It reduces round-trip overhead versus HTTP/1.1, speeding delivery of pages with many resources.
How is HTTP/2 negotiated between browser and server?
Over HTTPS, HTTP/2 is negotiated during the TLS handshake using ALPN (Application-Layer Protocol Negotiation). The client offers h2, and if the server agrees, the connection uses HTTP/2. This test reads exactly that ALPN result.
How do I enable HTTP/2 on my site?
Enable the HTTP/2 module in your web server or CDN (for example the http2 directive in modern server builds) and ensure HTTPS with ALPN is active. HTTP/2 in browsers effectively requires TLS, so a valid certificate is prerequisite.
What is the difference between HTTP/1.1 and HTTP/2?
HTTP/1.1 sends requests largely one-at-a-time per connection and can suffer head-of-line blocking. HTTP/2 multiplexes concurrent streams over one connection and compresses headers, cutting latency for resource-heavy pages without opening many parallel connections.
Does this test confirm HTTP/3 support?
No. HTTP/3 here is only inferred from the Alt-Svc response header, which advertises an h3 endpoint. This ALPN-based test confirms HTTP/2 directly but does not perform a QUIC handshake to prove HTTP/3 works.
Why does HTTP/2 require HTTPS?
The specification allows cleartext HTTP/2, but every major browser only supports it over TLS via ALPN. In practice you need a valid certificate and HTTPS for browsers to negotiate and use HTTP/2 at all.
What TLS version should my server use with HTTP/2?
TLS 1.3 is preferred for its faster handshake and stronger defaults, with TLS 1.2 as an acceptable minimum. HTTP/2's blocklist forbids obsolete ciphers, so modern TLS configuration avoids fallback to HTTP/1.1.
The test says HTTP/2 is not negotiated. What now?
Confirm HTTPS with ALPN is enabled and the HTTP/2 module is on at whichever layer terminates TLS, often a CDN or reverse proxy rather than your origin. Some hosts serve HTTP/2 only at the edge.
Does HTTP/2 make a page faster?
It can reduce request overhead when a page loads many resources, but this protocol check does not measure page rendering or real-user speed. Compare field and browser measurements before attributing a speed change to HTTP/2.