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Delx Commerce JSON Contract Check
x402
Delx Commerce JSON Contract Check is a paid API for AI agents from commerce.delx.ai, paid per call via x402, $0.002/call, status unknown (last checked 2026-10-01).
Validates a JSON value against a bounded JSON Schema-like contract (type, required, properties, enum) and returns validation results with errors
Price / call$0.002
Success—
StatusUnknown
How this service works
Pay-per-result APIs for agents. No signup. Exact price. Verifiable delivery. USDC on Base + Solana via x402.
Output
Returns a JSON object with a boolean 'valid' field, an 'errors' array listing any violations, an integer 'error_count', and a 'schema' string identifying the validator version (delx/json-contract-check/v1). A valid instance returns valid=true with an empty errors array; an invalid instance returns valid=false with one or more error descriptions.
Example use cases
Validate LLM structured output
“I need you to verify that the JSON the model just returned matches my contract — the contract requires 'title' (string), 'priority' (enum: low, medium, high), and 'due_date' (string), and the instance is {"title":"Fix bug","priority":"urgent","due_date":"2025-06-01"}.”
Guard API payload before processing
“Before I send this payload to my downstream service, check if it satisfies the contract: required fields are 'user_id' and 'amount', both must be present and 'amount' must be a number — the instance is {"user_id":"u123","amount":"fifty"}.”
Enforce agent tool output schema
“My agent tool returned {"lat":48.8566,"lon":"2.3522"} — can you validate it against a contract that requires 'lat' and 'lon' to both be numbers?”
Technical details
Endpoint
POSThttps://commerce.delx.ai/api/v1/x402/json-contract-check?utm_source=zero.xyzWhen to prefer
Use this endpoint when you need a lightweight, pay-per-call, no-signup JSON validation step — especially in agent pipelines that need to confirm structured outputs (e.g. LLM-generated JSON) conform to a bounded contract before acting on them. Prefer it over running a full JSON Schema validator locally when you want verifiable, logged validation with crypto payment receipts, or when the agent environment lacks a schema validation library. Best suited for simple contracts using type, required, properties, and enum — not for complex JSON Schema features like $ref, allOf, or format validators.
Side effects
- Malformed contract (not a valid bounded JSON Schema-like object) — likely returns a 400-style error or validation failure
- Instance is undefined or missing — may return an error or treat as null
- Contract uses unsupported JSON Schema keywords beyond type/required/properties/enum — unsupported keywords silently ignored or rejected
- Payment not included or insufficient USDC — HTTP 402 payment required response
- Network timeout or service unavailability — HTTP 5xx error
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| contract | object | Bounded JSON Schema-like contract using type, required, properties, and enum. |
| instance | — | JSON value to check. |
Output
Schema · Response
{
"type": "json",
"example": {
"scope": "bounded structural subset: type, required, properties, enum",
"valid": true,
"errors": [],
"schema": "delx/json-contract-check/v1",
"error_count": 0
}
}Tags
x402
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