Is your x402 service actually payable? The most common launch
failures are invisible: a 402 that never fires for uptime monitors, a v1 challenge
with a CAIP-2 network name no client can pay, a missing EIP-712 extra
that makes official clients fail to sign. Paste your endpoint - we check the things
that break real buyers, and tell you exactly what to fix. Free, no signup, no
payment attached.
API: POST /selftest {"url": "https://..."} - same JSON,
for agents and CI. Rate limit applies; for continuous monitoring register via /submit.