# HTTP/3 & Modern Transport Protocol Checker

> HTTP/3 & Modern Transport Protocol Checker is a paid API for AI agents from intel.rallylive.ca, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-14).

Checks a domain for HTTP/3 (QUIC), HTTP/2, and Encrypted Client Hello (ECH) support by inspecting DNS HTTPS records (ALPN, ECH, IP hints) and the Alt-Svc response header.

## Facts

- Endpoint: GET https://intel.rallylive.ca/monitor/http3
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/http-3-modern-transport-protocol-checker-8b748017
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_an5ewg5kEW7wF-x_3NLxx

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability http-3-modern-transport-protocol-checker-8b748017
```

Example prompt: Can you check whether cloudflare.com supports HTTP/3 and Encrypted Client Hello — I want to see what's in its DNS HTTPS record and Alt-Svc header?

## When to prefer this

Choose this endpoint when you need to specifically audit HTTP/3 (QUIC) and ECH readiness for a domain, combining both DNS HTTPS record inspection and Alt-Svc header analysis in a single call. Prefer this over generic DNS lookup endpoints when you need protocol-layer and transport-layer details together, especially for performance or security auditing workflows.

## Known failure modes

- Domain does not exist or fails DNS resolution — no results returned
- Domain does not have a DNS HTTPS record — ALPN and ECH fields will be absent or null
- Alt-Svc header not present on the domain's HTTP response — h3 advertisement not detectable
- Network timeout reaching the target domain — error response
- Invalid domain format provided — request rejected

## How this service works

HTTP/3 and modern-transport support: checks the DNS HTTPS record (alpn, ech, ipv4hint), the Alt-Svc response header for h3, and reports whether HTTP/3 (QUIC), HTTP/2 and Encrypted Client Hello are advertised. Useful for protocol-compatibility and performance audits. $0.01 per domain.

## Output

Returns a structured report indicating whether the domain advertises HTTP/3 (QUIC) and HTTP/2 support, details from the DNS HTTPS record (including ALPN values, ECH parameters, and IPv4 hints), and the Alt-Svc response header contents showing h3 advertisement status.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "properties": {}
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/http-3-modern-transport-protocol-checker-8b748017/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from intel.rallylive.ca](https://www.zero.xyz/host/intel.rallylive.ca/llms.txt)