MCP Config Validator

What this tool does

A small mistake in an MCP configuration is a common reason a server fails to connect. This validator takes your mcpServers JSON, parses it, and reports errors and warnings so you can fix problems before you hand the config to a client.

What it checks

• Valid JSON: it reports syntax errors with a hint about where they occur.
• Wrapper: it confirms the config has an mcpServers or servers object.
• Transport shape: for each server it checks whether the entry is a local stdio server (it has a command) or a remote server (it has a url), and flags entries that have neither or both.
• Common mistakes: it catches typos such as httpUrl instead of url, an args value that is not an array, a missing command, and a remote URL served over plain http.
• Secrets: it scans environment variables and headers for values that look like hard-coded tokens or keys and recommends using an environment variable reference instead.

How to use it

Paste your config into the box. The validator runs as you type and shows a list of errors in red and warnings in yellow, or a green looks-valid state. Everything runs in your browser, so your config is never uploaded.

Why secrets matter

A config committed with a real API key leaks that key to anyone who can read the repository. Keep secrets in environment variables and reference them from the config.

Related

Learn how to write these configs in the first place with our MCP server guide and the MCP Server Config Generator.