# JSON Schema Draft-04 Validator

> JSON Schema Draft-04 Validator is a paid API for AI agents from agentshelf.syntexa.ch, paid per call via x402, $0.005/call, status unknown (last checked 2026-10-24).

Validates a JSON value against a provided JSON Schema draft-04 schema, returning compliance results

## Facts

- Endpoint: POST https://agentshelf.syntexa.ch/v1/check-schema-draft-04?utm_source=zero.xyz
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-24
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/json-schema-draft-04-validator-c1304e85
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_spkMjzIHEQKp3cL1RY9Gy

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 json-schema-draft-04-validator-c1304e85 -d '<json body>'
```

Example prompt: Can you check whether this JSON value — {"age": 25, "name": "Alice"} — is valid against this draft-04 schema: {"type": "object", "properties": {"age": {"type": "integer", "minimum": 0}, "name": {"type": "string"}}, "required": ["name"]}?

## When to prefer this

Use this endpoint when you specifically need draft-04 JSON Schema validation and cannot use a free local validator. Prefer a free alternative (POST /v1/sandbox/check-schema-draft-04) first. Choose this paid endpoint when the free option is unavailable, rate-limited, or when operating in an automated pipeline that already handles x402 micropayments. Note that draft-04 has dialect-specific behavior around exclusiveMaximum/exclusiveMinimum and format keywords — use this only when draft-04 compatibility is explicitly required, not for draft-07 or later.

## Known failure modes

- Schema is not valid draft-04 (returns parse or dialect error)
- Value field is empty or exceeds 20,000 character limit (rejected by input constraints)
- Non-draft-04 schema features used (behavior undefined or incorrect due to dialect differences)
- Malformed JSON in schema or value field (parse error returned)
- Network or payment failure prevents the call from completing

## How this service works

Call when an agent needs a limited JSON Schema draft-04 check. Dialects disagree on exclusive bounds and format. Exact $0.005 USDC. Prefer unpaid POST /v1/sandbox/check-schema-draft-04 first.

## Output

Returns a validation result indicating whether the provided JSON value conforms to the given draft-04 schema, including any specific errors, property violations, or format/exclusive-bound issues detected during the check.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "data": {
   "examples": [
    {
     "a": 1
    }
   ],
   "description": "JSON value for schema-check SKUs. Omit it on string checks such as email or IBAN."
  },
  "value": {
   "type": "string",
   "examples": [
    "{\"a\":1}"
   ],
   "maxLength": 20000,
   "minLength": 1,
   "description": "Value to check. The route description names the format: email, phone, IBAN, postal code, VAT, national id, or similar."
  },
  "schema": {
   "examples": [
    {
     "type": "object",
     "required": [
      "a"
     ],
     "properties": {
      "a": {
       "type": "integer"
      }
     }
    }
   ],
   "description": "JSON Schema document for schema-check SKUs. Omit it on string checks."
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/json-schema-draft-04-validator-c1304e85/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from agentshelf.syntexa.ch](https://www.zero.xyz/host/agentshelf.syntexa.ch/llms.txt)