Free MCP developer tools
Browser-based utilities for building, inspecting, validating, and optimizing Model Context Protocol (MCP) servers and client configurations. Free, no sign-in, and the config tools never send your JSON anywhere.
Configure
Pick servers and get a working client config without hand-editing JSON.
- Stack BuilderCombine several servers into one config for Claude, Cursor, Cline, or Windsurf.Free · no sign-in
- Config GeneratorBuild a ready-to-paste client config from directory servers or your own.Free · no sign-in
- Config ValidatorCatch syntax errors, missing fields, and path mistakes before you restart.Free · no sign-in
- Config Auditor & MergerFind leftover API-key placeholders and merge directory servers in one click.Free · no sign-in
- Server ComparisonCompare 2–4 servers side by side on tools, install, stars, and security.Free · no sign-in
Test & debug
Talk to a live server, inspect what it returns, and measure what it costs.
- MCP PlaygroundSend initialize, tools/list, and tools/call to a remote endpoint and read the reply.Free · no sign-in
- Protocol InspectorConnect to a live server or validate a JSON-RPC payload against the spec.Free · no sign-in
- Token CalculatorSee how much of your context window your servers’ tool schemas eat each turn.Free · no sign-in
Build & ship
Turn an existing API into an MCP server and promote it once it is listed.