# Json Schema Validator — MCP tool `findutils:json_schema_validator`

Returns whether a JSON document is valid against a JSON Schema (draft-07 subset) and lists every violation with its JSON pointer path, message and keyword. Checks type, required, properties, items, min/maxLength, pattern, format, minimum, maximum, enum and min/maxItems.

- Category: seo
- MCP server: https://mcp.findutils.com/ (Streamable HTTP, no API keys, 120 req/min per IP)
- REST endpoint: POST https://api.findutils.com/api/tools/json-schema-validator/execute (no API keys, 60 req/min per IP)
- Reference page: https://findutils.com/mcp/json-schema-validator/
- Same tool on the other surface: https://findutils.com/api/json-schema-validator/

## Connect

```bash
claude mcp add findutils --transport http https://mcp.findutils.com/
```

Claude Desktop (`claude_desktop_config.json`):

```json
{
  "mcpServers": {
    "findutils": {
      "url": "https://mcp.findutils.com/"
    }
  }
}
```

## Call the tool (verified example)

```bash
curl -X POST https://mcp.findutils.com/ \
  -H "Content-Type: application/json" \
  -d '{
    "jsonrpc": "2.0",
    "id": 1,
    "method": "tools/call",
    "params": {
      "name": "json_schema_validator",
      "arguments": {
        "schema": "{\"type\":\"object\",\"required\":[\"name\"],\"properties\":{\"name\":{\"type\":\"string\"}}}",
        "data": "{\"name\":\"Ann\"}"
      }
    }
  }'
```

## Input schema

| Argument | Type | Required | Description |
|---|---|---|---|
| `schema` | string | yes | The JSON Schema (text). |
| `data` | string | yes | The JSON document to validate (text). |

Example arguments (verified):

```json
{
  "schema": "{\"type\":\"object\",\"required\":[\"name\"],\"properties\":{\"name\":{\"type\":\"string\"}}}",
  "data": "{\"name\":\"Ann\"}"
}
```

Decoded `schema` argument (readability only — send it as a string):

```json
{
  "type": "object",
  "required": [
    "name"
  ],
  "properties": {
    "name": {
      "type": "string"
    }
  }
}
```

Decoded `data` argument (readability only — send it as a string):

```json
{
  "name": "Ann"
}
```

## Also a REST endpoint

```bash
curl -X POST https://api.findutils.com/api/tools/json-schema-validator/execute \
  -H "Content-Type: application/json" \
  -d '{
    "schema": "{\"type\":\"object\",\"required\":[\"name\"],\"properties\":{\"name\":{\"type\":\"string\"}}}",
    "data": "{\"name\":\"Ann\"}"
  }'

# Parameter schema
curl https://api.findutils.com/api/tools/json-schema-validator
```

Full REST reference: https://findutils.com/api/json-schema-validator/ · OpenAPI 3.1 spec: https://findutils.com/api/openapi.json

---
Full catalog: POST https://mcp.findutils.com/ with method `tools/list` · https://findutils.com/mcp/ · https://findutils.com/llms.txt