# JSON Validator with Optional JSON Schema Check

> JSON Validator with Optional JSON Schema Check is a paid API for AI agents from json-validator.api.klymax402.com, paid per call via x402, $0.003/call, status unknown (last checked 2026-09-15).

Validates a JSON string for syntactic correctness and optionally validates it against a provided JSON Schema

## Facts

- Endpoint: GET https://json-validator.api.klymax402.com/api/validate
- Price: $0.003/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/json-validator-with-optional-json-schema-check-4dddd4bd
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_fSMzyA8eOJJ2---9b6GJ6

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-validator-with-optional-json-schema-check-4dddd4bd
```

Example prompt: Can you check if this JSON is valid and also verify it conforms to my schema? Here's the JSON: {"name":"Alice","age":30} and the schema requires 'name' as a string and 'age' as an integer.

## When to prefer this

Use this endpoint when you need to quickly verify that a JSON string is syntactically correct and/or structurally valid against a known JSON Schema. Ideal for API development, data pipeline validation, form submission checking, or automated testing workflows where you need a lightweight, stateless JSON validation call without setting up a local validator.

## Known failure modes

- Malformed or empty 'json' parameter returns a parse error
- Invalid JSON Schema object causes schema validation to fail or be skipped
- Very large JSON strings may time out or be rejected
- Missing required 'json' parameter returns a 400-level error
- Schema references external $ref URIs that cannot be resolved

## How this service works

Validate JSON and optionally check against a JSON Schema

## Output

The agent receives a response indicating whether the JSON string is syntactically valid, and if a JSON Schema was provided, whether the JSON conforms to that schema — including any specific validation errors or mismatches detected.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "json": {
   "type": "string",
   "description": "JSON string to validate"
  },
  "schema": {
   "type": "object",
   "description": "Optional JSON Schema to validate against"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/json-validator-with-optional-json-schema-check-4dddd4bd/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from json-validator.api.klymax402.com](https://www.zero.xyz/host/json-validator.api.klymax402.com/llms.txt)