About Json Validator X402
Json Validator X402 is a JSON validation API for AI agents and developers. It checks syntax, optionally validates against JSON Schema, and returns formatted data and structure statistics, with x402 pay-per-call access.
Key features
- 01Validate JSON syntax
- 02Check data against JSON Schema
- 03Return parse errors and formatted JSON
- 04Report structure statistics
- 05Pay per call with USDC on Base
Use cases
- 01Check generated JSON before passing it to another tool
- 02Validate an API payload against a JSON Schema
- 03Inspect JSON size, depth, keys, and arrays
MCP support
Provides the `data_validate_json` tool to MCP clients at a remote endpoint. Calls use x402 micropayments in USDC on Base.
Configuration
Remote servers need no local install. Pick your client, then copy the config or install in one click.
https://json-validator.api.klymax402.com/mcpclaude mcp add --transport sse json-validator-x402 https://json-validator.api.klymax402.com/mcp{"mcpServers":{"json-validator-x402":{"type":"sse","url":"https://json-validator.api.klymax402.com/mcp"}}}Open in Cursor{"servers":{"json-validator-x402":{"type":"sse","url":"https://json-validator.api.klymax402.com/mcp"}}}Open in VS Code{"mcpServers":{"json-validator-x402":{"type":"sse","url":"https://json-validator.api.klymax402.com/mcp"}}}{"mcpServers":{"json-validator-x402":{"serverUrl":"https://json-validator.api.klymax402.com/mcp"}}}Run commands in a terminal; paste JSON into the client’s MCP config and restart. Servers that need sign-in will prompt on first connect.
Tools
Details
From the project READMEJSON 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
| Tool | Method | Path | Price | Description |
|---|---|---|---|---|
data_validate_json | POST | /api/validate | $0.003 | Validate 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
| Name | Type | Required | Description |
|---|---|---|---|
json | string | yes | JSON string to validate |
schema | object | no | Optional 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.
- Catalog: https://klymax402.com/llms.txt
- Full API reference: https://klymax402.com/llms-full.txt
- Live stats: https://klymax402.com/stats
License
MIT
Comments
New to MCP?
From what the protocol is to installing your first server, these answers cover most first questions.
An open protocol that defines how AI applications connect to external tools and data in a uniform way. Clients talk to the model; MCP servers provide tools, resources and prompt templates. They exchange standard messages, so one server can be reused by many clients.