x402-endpoint-validator

Validate x402 endpoints — test 402 responses, check Bazaar extension, verify payment schemas, confirm .well-known/x402 discovery manifests. For agents and operators who want to verify their x402 implementation works correctly.

Test and validate x402 endpoints. Check that the 402 payment challenge is correctly configured, the Bazaar extension is present, and the .well-known discovery manifest is valid.

What This Validates

1. 402 Response: Does the endpoint return HTTP 402 with proper payment requirements?
2. Payment Schema: Is the accepts array valid (asset, network, payTo, amount)?
3. Bazaar Extension: Does the response include extensions.bazaar with discovery metadata?
4. Well-Known Manifest: Does /.well-known/x402 exist and contain valid JSON?
5. Crawl vs Sync: Does the service return results in the same response or queue a job?

Validate a Single Endpoint

bash

# Trigger a 402 (replace URL and body with the service's expected input)
curl -s -o /dev/null -w "%{http_code}" -X POST https://service.example/services/your-endpoint/jobs \
  -H "Content-Type: application/json" \
  -d '{"url": "https://example.de"}'

Expected: 402

Inspect the Full 402 Response

bash

curl -s -X POST https://service.example/services/your-endpoint/jobs \
  -H "Content-Type: application/json" \
  -d '{"url": "https://example.de"}' | python3 -m json.tool

Check these fields:

Field	Expected	Check
x402Version	2	Protocol version
accepts[].scheme	"exact"	Payment scheme
accepts[].network	"eip155:8453"	Base mainnet
accepts[].asset	"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913"	USDC contract
accepts[].amount	valid number string	In atomic units (6 decimals)
accepts[].payTo	valid address	Where to send payment
accepts[].maxTimeoutSeconds	number	Max wait for result
extensions.bazaar	present	Bazaar discovery metadata
extensions.bazaar.discoverable	true	Indexed on Bazaar

Validate Well-Known Manifest

bash

curl -s https://service.example/.well-known/x402 | python3 -m json.tool

Check:

• x402Version = 2
• serviceName, claim, description are present
• facilitator is declared (e.g. "cdp")
• resources array is non-empty
• Each resource has: url, description, network, payTo, asset, amount, inputSchema

Validate with Agentic Market

Use the official validator at https://agentic.market/validate:

1. Select HTTP method (GET/POST/etc.)
2. Enter your endpoint URL
3. Click Validate

The tool checks x402 configuration, facilitator setup, and Bazaar indexing.

Common Issues

Symptom	Likely Cause
HTTP 200 instead of 402	Endpoint not x402-configured
Missing accepts array	Payment schema not declared
Wrong asset address	USDC on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913
No extensions.bazaar	Bazaar metadata not included
/.well-known/x402 returns 404	Discovery manifest not published
Amount too high/low	Check atomic units (50000 = $0.05)
PAYMENT-SIGNATURE rejected	Wrong tx hash, amount mismatch, or expired quote