# Tanod JSON Schema Validation

> Tanod JSON Schema Validation is a paid API for AI agents from tanod.dev, paid per call via x402, $0.001/call, status unknown (last checked 2026-10-11).

Validates a JSON value against a JSON Schema (draft 2020-12 default) and returns detailed error paths

## Facts

- Endpoint: POST https://tanod.dev/v1/json/validate?utm_source=zero.xyz
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-11
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/tanod-json-schema-validation-bfdf4b39
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_cSzgWIV-9ZZboWCzl3dpZ

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 tanod-json-schema-validation-bfdf4b39 -d '<json body>'
```

Example prompt: Can you validate this JSON object against my schema and show me exactly which fields fail and why? My schema requires `name` to be a string and `age` to be a positive integer, and the instance I want to check is `{"name": 42, "age": -5}`.

## When to prefer this

Choose this endpoint when you need authoritative JSON Schema validation with precise error paths, especially when using JSON Schema draft 2020-12 and when remote $ref security isolation is important. Prefer it over client-side libraries when the agent environment lacks a suitable validator, when auditability of validation results matters, or when you need pay-per-call validation without managing dependencies.

## Known failure modes

- Invalid or malformed JSON Schema provided — returns schema parse error
- Schema references remote $ref URLs — refused and returns an error since remote fetching is disabled
- Malformed request body missing required `schema` or `instance` fields — returns 400-level error
- Payment not provided or insufficient — returns 402 Payment Required
- Schema draft version mismatch or unsupported draft — may return partial results or error

## How this service works

One MCP server and HTTP API with 193 pay-per-call tools for AI agents (security checks, chain data, finance, aviation, documents), plus free uptime and MikroTik monitoring and 130+ free browser tools. No signup; free daily tier. Operated by an AI.

## Output

Returns a structured JSON response indicating whether the instance is valid against the provided schema, along with detailed error paths and messages for each validation failure, using JSON Schema draft 2020-12 semantics by default. Remote $ref documents are never fetched.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "schema": {
   "anyOf": [
    {
     "type": "object",
     "additionalProperties": true
    },
    {
     "type": "boolean"
    }
   ],
   "description": "JSON Schema (draft from $schema; default 2020-12). Remote $ref documents are refused, never fetched."
  },
  "instance": {
   "type": [
    "object",
    "array",
    "string",
    "number",
    "integer",
    "boolean",
    "null"
   ],
   "description": "Any JSON value to validate."
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "note": "Remote $ref documents are never fetched; embed them under $defs. Formats not listed in formats_checked are not asserted.",
  "draft": "2020-12",
  "valid": false,
  "errors": [
   {
    "path": "",
    "message": "'age' is a required property",
    "validator": "required",
    "schema_path": "/required"
   },
   {
    "path": "/name",
    "message": "1 is not of type 'string'",
    "validator": "type",
    "schema_path": "/properties/name/type"
   },
   {
    "path": "/email",
    "message": "'nope' is not a 'email'",
    "validator": "format",
    "schema_path": "/properties/email/format"
   }
  ],
  "source": {
   "library": "jsonschema",
   "license": "MIT"
  },
  "truncated": false,
  "error_count": 3,
  "formats_checked": [
   "date",
   "date-time",
   "email",
   "idn-email",
   "idn-hostname",
   "ipv4",
   "ipv6",
   "regex",
   "time",
   "uri",
   "uri-reference",
   "uuid"
  ]
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/tanod-json-schema-validation-bfdf4b39/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from tanod.dev](https://www.zero.xyz/host/tanod.dev/llms.txt)