Deterministic validation of structured AI-agent tool-result envelopes. Free basic API and optional Base mainnet x402 validation.
Paid verification
How it worksNo sponsored paid call yet.
Pay this endpoint once from your own wallet (Base USDC, up to $1.00) and we call it and record what came back. Your wallet pays the listed recipient directly; Agent Tools never holds funds. Sponsored checks prove delivery; they do not count as demand.
Quality grade
How grading works- ✓ Answers a real HTTP 402 challenge
- ✓ Publishes a /.well-known/x402 descriptor
- ✓ Payment address on record
- ✓ Settlement network declared
- ✓ Price declared
x402 readiness
Readiness is how fully this listing follows its protocol and how it behaved in our probes over 30 days. It is shown for reference and does not move it in search. Search order and leaderboards use the separate quality grade (here B, 63.1/100), which weighs availability, payability and on-chain demand. How the two differ
| Valid payment requirements | 10/10 | Payment requirements carry a payee, a mainnet network and a price. |
| Live 402 challenge | 25/25 | Paid endpoint answers with an HTTP 402 challenge (172 ms). |
| x402 version | n/a | x402 version not observed yet. |
| Signed descriptor | n/a | No x402 standard defines a signed descriptor. |
| Uptime (30 days) | 15/15 | 7/7 probes succeeded over 30 days (100%). |
| Resource declaration | 5/10 | Declares 2 paid resource(s). |
| Verified identity | 5/10 | Publisher descriptor (/.well-known/x402 or OpenAPI) on record; claim this listing to verify domain control. |
| Freshness + modern flags | 3/5 | seen within 30 days; declares x402. |
| Security declaration | n/a | Payment is the access control for an x402 resource. |
Compared with peers
Against 10,082 reachable x402 APIs in our daily snapshot (2026-11-12 06:46 UTC). Display only; it does not change search order.
- Readiness
- Higher than 67% of peers
- This listing 84 · peer median 78
- Latency
- Faster than 60% of peers
- This listing 172 ms · peer median 205 ms
Where it loses the most points, and how to win them back
- Resource declaration −5
— Declare each paid resource with its input and output schema.
Now: Declares 2 paid resource(s).
- Verified identity −5
— Claim the listing and prove control of its domain.
Now: Publisher descriptor (/.well-known/x402 or OpenAPI) on record; claim this listing to verify domain control.
- Freshness + modern flags −2
— Keep the listing current in the registry or source it comes from.
Now: seen within 30 days; declares x402.
Paid endpoints
2 resource(s) advertised by this origin. Each price below is that resource's own x402 price; the headline price is the range across them.
https://apex-agent-tool-result-validator.apex-ai-assets.workers.dev/v1/premium/validate?payload=<url-encoded-json-object>
One deterministic Agent Tool Result Envelope v1.0 validation result. Base Sepolia testnet only.
https://apex-agent-tool-result-validator.apex-ai-assets.workers.dev/v1/premium/mainnet/xpay/validate?payload=%7B%22schema_version%22%3A%221.0%22%2C%22tool_name%22%3A%22inventory_lookup%22%2C%22status%22%3A%22ok%22%2C%22request_id%22%3A%22req_123%22%2C%22timestamp%22%3A%222026-10-30T00%3A00%3A00Z%22%2C%22payload%22%3A%7B%22sku%22%3A%22demo-001%22%2C%22available%22%3Atrue%7D%7D
$0.0050 / call
JSON tool response validation for one bounded Agent Tool Result Envelope v1.0: receive deterministic, test-fixture-compatible JSON errors for MCP and agent-tool output contracts. Base mainnet USDC via the separately selected xpay exact-v2 facilitator lane.
How to call
curl -sS -i -X GET 'https://apex-agent-tool-result-validator.apex-ai-assets.workers.dev/v1/premium/mainnet/xpay/validate?payload=%7B%22schema_version%22%3A%221.0%22%2C%22tool_name%22%3A%22inventory_lookup%22%2C%22status%22%3A%22ok%22%2C%22request_id%22%3A%22req_123%22%2C%22timestamp%22%3A%222026-10-30T00%3A00%3A00Z%22%2C%22payload%22%3A%7B%22sku%22%3A%22demo-001%22%2C%22available%22%3Atrue%7D%7D' # expect HTTP 402 Payment Required (about 0.005 USDC/call)Listed in
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