MCP config validator
Paste your mcpServers config and it's checked instantly — the validator catches the silent killers MCP clients fail on without telling you (a trailing comma, smart quotes, wrong nesting, unescaped Windows paths), points at the line, and formats the result. Everything runs in your browser.
Paste your mcpServers config — it's checked instantly, nothing leaves your browser.
FAQ
Why does my MCP config fail with no error?
MCP clients parse the config silently — a syntax error just makes them load nothing instead of showing a message. This validator surfaces the exact error (and line) so you can see what the client won't tell you.
Is my config sent anywhere?
No. The validator runs entirely in your browser — your config and any API keys in it never leave your machine.
What's the correct mcpServers structure?
{ "mcpServers": { "name": { "command": "npx", "args": ["-y", "package"], "env": { "KEY": "value" } } } } — one top-level mcpServers object, no trailing comma after the last entry.