# x402 Doctor – Diagnose x402 Payment Endpoint

> x402 Doctor – Diagnose x402 Payment Endpoint is a paid API for AI agents from x402-doctor.fizzl.eu, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-10).

Diagnoses and debugs an x402 payment endpoint by running a suite of read-only checks across the 402 challenge, accepts configuration, resource URL, Solana settlement readiness, wallet/agent compatibility, and discovery/browser paywall setup, returning each check with a status and fix hint.

## Facts

- Endpoint: GET https://x402-doctor.fizzl.eu/api/v1/diagnose?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-10
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/x402-doctor-diagnose-x402-payment-endpoint-ec454433
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_MVaORFkAjoLV4EIAcYfRe

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 x402-doctor-diagnose-x402-payment-endpoint-ec454433
```

Example prompt: Can you diagnose why my x402 payment endpoint at https://my-api.example.com/premium-data is broken — check the 402 challenge, accepts config, Solana settlement readiness, and tell me which wallets and agents can actually pay it?

## When to prefer this

Use this endpoint when an x402-protected API or MCP server is behaving unexpectedly — payments failing, agents unable to transact, or the paywall not rendering in browsers. It is the go-to read-only diagnostic tool covering every layer of the x402 stack (challenge format, accepts[] config, settlement, wallet compatibility, and discovery) in a single call, without ever executing a real payment.

## Known failure modes

- Target URL is not publicly reachable (network timeout or DNS failure)
- Endpoint does not return a 402 response at all (not an x402 endpoint)
- Malformed or missing 402 challenge header prevents check execution
- Solana RPC unavailable causing settlement checks to be skipped
- Invalid URL format provided as input

## How this service works

Why is my x402 endpoint broken? Diagnose and debug an x402 payment endpoint (or MCP server) when payments fail: checks the 402 challenge, accepts[] (network, payTo, amount, asset), resource URL, Solana settlement readiness, which wallets and agents can pay, Bazaar/OpenAPI discovery and the browser paywall. Returns every check with a fix hint. Read-only: never pays.

## Output

Returns an overall pass/warn/fail status, a list of individual checks (each with an id, group, status, message, and optional fix hint), the detected HTTP method, the parsed 402 challenge object, and a per-wallet breakdown showing which networks allow payment and which fail with reasons.

## 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",
     "required": [
      "url"
     ],
     "properties": {
      "url": {
       "type": "string",
       "description": "The x402 endpoint to diagnose (public http(s) URL)."
      },
      "method": {
       "enum": [
        "GET",
        "POST"
       ],
       "type": "string",
       "description": "HTTP method of the endpoint. Default: try GET, then POST."
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "required": [
      "url",
      "overall",
      "checks"
     ],
     "properties": {
      "url": {
       "type": "string"
      },
      "checks": {
       "type": "array",
       "items": {
        "type": "object",
        "required": [
         "id",
         "status",
         "message"
        ],
        "properties": {
         "id": {
          "type": "string"
         },
         "hint": {
          "type": "string"
         },
         "group": {
          "enum": [
           "challenge",
           "accepts",
           "resource",
           "settlement",
           "wallets",
           "discovery",
           "browser"
          ],
          "type": "string"
         },
         "status": {
          "enum": [
           "pass",
           "warn",
           "fail",
           "info",
           "skip"
          ],
          "type": "string"
         },
         "message": {
          "type": "string"
         }
        }
       }
      },
      "method": {
       "enum": [
        "GET",
        "POST",
        null
       ],
       "type": [
        "string",
        "null"
       ]
      },
      "overall": {
       "enum": [
        "pass",
        "warn",
        "fail"
       ],
       "type": "string"
      },
      "wallets": {
       "type": "array",
       "items": {
        "type": "object",
        "properties": {
         "no": {
          "type": "array",
          "items": {
           "type": "object",
           "p
… (truncated)
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/x402-doctor-diagnose-x402-payment-endpoint-ec454433/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402-doctor.fizzl.eu](https://www.zero.xyz/host/x402-doctor.fizzl.eu/llms.txt)