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JsonMend MCP Server

by workers-mike-tusa-jsonmend Your server? Claim it
answering

JsonMend is answering right now. Last checked 3 min ago. It exposes 2 tools.

Repair broken JSON from LLM output and validate it against a JSON Schema.

Uptime history 10 days of history
10 days agonow
100.0%
Uptime 24h
92 of 92 checks
2
Tools
read from the server
210 ms
Response time
average over 24h
open, no key
Access
streamable-http

What changed 1

Every tool that appeared, vanished or quietly changed what it asks for. Recorded since 16 October 2026. No other catalogue keeps this.

16 Oct a tool changed version

Nothing serious here today

Today is the operative word: we check JsonMend every 15 minutes and re-read its code on every release. Watch it and you find out the day that stops being true.

Three servers free · no card

Connect this server

Endpoint below is the one we actually reach during checks — not the one copied from a README. Last verified 3 min ago.

run in your terminal
claude mcp add jsonmend --transport http https://jsonmend.mike-tusa.workers.dev/mcp
Settings → Connectors → Add custom connector, then paste this address
https://jsonmend.mike-tusa.workers.dev/mcp
~/.codex/config.toml
[mcp_servers.jsonmend]
url = "https://jsonmend.mike-tusa.workers.dev/mcp"
.cursor/mcp.json
{
  "mcpServers": {
    "jsonmend": {
      "url": "https://jsonmend.mike-tusa.workers.dev/mcp"
    }
  }
}
.vscode/mcp.json
{
  "servers": {
    "jsonmend": {
      "type": "http",
      "url": "https://jsonmend.mike-tusa.workers.dev/mcp"
    }
  }
}

Available tools 2

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

repair
repair_json
Turn broken or messy JSON text into valid JSON. Strips Markdown code fences and prose before/after the JSON, removes comments and trailing commas, converts single/curly quotes, quotes unquoted keys, maps Python None/True/False, inserts missing commas, closes truncated strings/arrays/objects, and wraps NDJSON / several concatenated objects into one array. Returns the parsed value (json), the repaired text, and the list of fixes applied; valid input passes through unchanged with no fixes. Optional schema (+ coerce) also validates the result. Fails with isError (code unrepairable / no_json_found) when nothing JSON-like can be recovered. Pure computation: read-only, no network access, inputs not stored. Same engine and limits as POST /api/v1/repair.
validate
validate_json
Check JSON against a JSON Schema and get every error with its JSON Pointer path. Send the JSON either as text ("input"; broken text is repaired first, and the fixes are listed) or as an already-parsed value ("data"). Optional coerce converts "42" → 42, "true" → true, etc. toward the schema's types before validating and lists each change. A schema mismatch is a normal result (valid: false), not an error. Drafts 2020-12 (default), 2019-09, 7, 4; only local $refs. Pure computation: read-only, no network access, inputs not stored. Same engine and limits as POST /api/v1/validate.

Endpoints

URLTransportStateLatencyChecked
https://jsonmend.mike-tusa.workers.dev/mcp streamable-http answering 95 ms 3 min ago

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JsonMend — questions

Answers built from our own checks of this server.

What can JsonMend do?
It exposes 2 tools, read directly from the server on our last check. Among them: repair_json, 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 JsonMend working right now?
We send a real MCP handshake every 15 minutes. Over the last 24 hours 92 of 92 checks got a reply (100.0%), average response time 210 ms. The bar chart above shows every period we have measured.
How do I connect JsonMend?
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 JsonMend need an API key?
No. JsonMend completed a full MCP handshake with us as an anonymous client and listed its tools without asking for anything. All 2 of them are readable on this page. This is what we observed, not what the docs claim.
How fast is JsonMend?
It answers our handshake in 210 ms on average, which is faster than 76% of all working MCP servers we measure. That puts it in the quick quarter of the ecosystem. The comparison comes from our own checks across the whole registry, every 15 minutes.