JSON Validator API MCP Server

by br0ski777 Your server? Claim it

not responding

JSON Validator API is listed as active in the registry but did not answer our last check. It exposes 1 tools. Last commit 2 Sep 2026.

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

Uptime history 91 days of history · worst day 0%

91 days agonow

0.0%

Uptime 24h

0 of 91 checks

Tools

read from the server

8 ms

Response time

average over 24h

Stars

last commit 2 Sep 2026

JSON Validator API does not always answer

Over the last week it answered 0.0% of our checks. We check every 15 minutes, so you hear about the next outage within the hour — not from your users.

Connect this server

Endpoint below is the one we actually reach during checks — not the one copied from a README. Last verified 9 min ago.

Claude Code Claude Desktop Codex Cursor VS Code

run in your terminal

claude mcp add json-validator --transport sse https://json-validator.api.klymax402.com/mcp

Settings → Connectors → Add custom connector, then paste this address

https://json-validator.api.klymax402.com/mcp

~/.codex/config.toml

[mcp_servers.json-validator]
url = "https://json-validator.api.klymax402.com/mcp"

.cursor/mcp.json

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

.vscode/mcp.json

{
  "servers": {
    "json-validator": {
      "type": "sse",
      "url": "https://json-validator.api.klymax402.com/mcp"
    }
  }
}

Available tools 1

Read directly from the server with tools/list, grouped by what they act on. If a tool disappears, we record the date.

data

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.

Endpoints

URL	Transport	State	Latency	Checked
https://json-validator.api.klymax402.com/mcp	sse	answering	8 ms	9 min ago

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JSON Validator API — questions

Answers built from our own checks of this server.

What can JSON Validator API do?

It exposes 1 tools, read directly from the server on our last check. Among them: data_validate_json. The full list with descriptions is on this page — we take it from the server itself via tools/list, not from a README. How MCP servers expose tools in the first place →

Is JSON Validator API working right now?

We send a real MCP handshake every 15 minutes. Over the last 24 hours 0 of 91 checks got a reply (0.0%), average response time 8 ms. The bar chart above shows every period we have measured.

The registry lists JSON Validator API as active — why does it not respond?

The official MCP registry stores what the author submitted; it does not verify that the server still runs. We check the endpoint ourselves, and this one does not answer. Catalogues that copy the registry without checking will show it as working.

How do I connect JSON Validator API?

Copy the ready config from this page. We generate it for Claude Code, Claude Desktop, Codex, Cursor and VS Code, each in the form that client actually reads. It is a remote server, so there is nothing to install — the client connects to the address.

Does JSON Validator API need an API key?

No. JSON Validator API completed a full MCP handshake with us as an anonymous client and listed its tools without asking for anything. All 1 of them are readable on this page. This is what we observed, not what the docs claim.

Is JSON Validator API open source?

The code is open source: it is published under the MIT licence, written in TypeScript and 0 stars on GitHub. The licence covers the code in the repository, not the hosted service at json-validator.api.klymax402.com, which runs on its operator's own terms.