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JSON Validator API

Official registry Developer tools

JSON syntax validation, JSON Schema checking, structure stats. x402 micropayment.

Source code Website Documentation

Install

Add this to your client's MCP configuration (Claude Desktop: claude_desktop_config.json; Cursor: .cursor/mcp.json; VS Code and others use the same "mcpServers" shape).

Remote (sse)
Claude Code 
claude mcp add --transport sse json-validator-api 'https://json-validator.api.klymax402.com/mcp'
JSON configuration (Claude Desktop, Cursor, VS Code) 
{
    "mcpServers": {
        "json-validator-api": {
            "type": "sse",
            "url": "https://json-validator.api.klymax402.com/mcp"
        }
    }
}

Documentation

From the project's README on GitHub, refreshed weekly. Links open on GitHub.

Contents
  1. JSON Validator API
  2. Quickstart -- MCP
  3. Quickstart -- HTTP (x402)
  4. Tools
  5. Example agent prompts
  6. Payment
  7. Part of klymax402
  8. License

JSON Validator API

JSON validator with optional JSON Schema validation and structure stats. Pay-per-call via x402 (USDC on Base L2) -- no API key, no signup, no rate-limit wall.

Part of the klymax402 marketplace -- 100 x402 micropayment APIs for AI agents, one wallet, USDC on Base.

Quickstart -- MCP

Add to your MCP client config (Claude Desktop, Cursor, ElizaOS, etc.):

{
  "mcpServers": {
    "json-validator": {
      "url": "https://json-validator.api.klymax402.com/mcp"
    }
  }
}

Quickstart -- HTTP (x402)

curl -X POST "https://json-validator.api.klymax402.com/api/validate" \
  -H "Content-Type: application/json" \
  -d '{"json":"..."}'
# -> 402 Payment Required, with an x402 payment challenge in the response body

Any x402-aware client (@x402/fetch, x402-agent-tools, ATXP) handles the 402 -> sign -> retry cycle automatically.

Tools

ToolMethodPathPriceDescription
data_validate_jsonPOST/api/validate$0.003Validate JSON and optionally check against a JSON Schema
data_validate_json

Use this when you need to validate JSON syntax or validate JSON data against a JSON Schema. Returns validity status, parse errors, formatted JSON, and structure stats (depth, key count, arrays, total size). Do NOT use for password checking — use security_check_password. Do NOT use for hash generation — use crypto_generate_hash. Do NOT use for cron expressions — use util_parse_cron.

Parameters

NameTypeRequiredDescription
jsonstringyesJSON string to validate
schemaobjectnoOptional JSON Schema to validate against

Example agent prompts

  • "Validate JSON syntax or validate JSON data against a JSON Schema"

Payment

  • Protocol: x402 -- HTTP-native pay-per-call, no signup, no API key
  • Network: Base L2 (eip155:8453)
  • Asset: USDC
  • Facilitator: Coinbase CDP (primary), PayAI (fallback)

Part of klymax402

100 x402 micropayment APIs for AI agents -- one wallet, USDC on Base, zero signup.

License

MIT

Frequently asked questions

What is JSON Validator API?

JSON syntax validation, JSON Schema checking, structure stats. x402 micropayment.

How do I install JSON Validator API?

It runs as a remote server. In Claude Code: claude mcp add --transport sse json-validator-api 'https://json-validator.api.klymax402.com/mcp'. For other clients, paste the JSON configuration from this page into their MCP settings.

Does JSON Validator API need an API key?

Its registry entry lists no required key or secret. Some features may still need an account with the service it connects to.

Is JSON Validator API open source?

Yes. Its code is on GitHub under the MIT license.

Who maintains JSON Validator API?

It is published by Br0ski777. AI.tn lists it but does not maintain or endorse it.

From the official MCP Registry. Listing is not an endorsement: review a server's code and permissions before giving it access to your data.