Test MCP Servers Instantly with MCPJam Inspector
Launch MCPJam via web (HTTPS), terminal (npx), or desktop to test MCP servers in minutes: connect HTTP/STDIO endpoints, debug apps/widgets with Excalidraw demo, and explore chat/OAuth tools—no install or API keys needed.
Launch MCPJam Without Installation Friction
MCPJam Inspector runs MCP servers across web, terminal, or desktop for seamless team sharing and local testing. Web version handles HTTPS URLs only and shares server links with teammates. Terminal uses npx @mcpjam/inspector@latest for HTTP/S and STDIO support. Desktop apps (Mac/Windows) add local STDIO, enabling commands like npx -y @modelcontextprotocol/server-everything. This setup skips ngrok, paid subs, or API keys, letting you inspect JSON-RPC, tool calls, widgets, CSP, and state directly.
Hands-On First Test Reveals Tool Call Flow
On launch, MCPJam auto-connects the Excalidraw diagramming server and loads App Builder with the prompt: "Draw me an MCP architecture diagram". Send it to trigger sequence: tool call → widget render → inspect. Debug icons expose tool input/output, CSP activity, widget state, and JSON-RPC. Toggle views (Chat, Trace, Raw) or emulate iframes, window.openai, device frames, locales. This zero-config demo teaches MCP app rendering for OpenAI Apps SDK, plain text tools, and UIs, building intuition for production debugging.
Connect Custom Servers for Real-World Inspection
From sidebar Servers panel, add HTTP endpoints (paste URL ending /mcp; web requires HTTPS, others accept HTTP/S) with bearer tokens or OAuth via Guided OAuth Debugger. STDIO (desktop/terminal only) runs commands directly. Connected servers persist across App Builder, Chat, Tools/Prompts/Resources. OAuth Debugger steps through flows, checks conformance (versions 03-26, 06-18, 11-25), and supports DCR, pre-registration, CIMD—ensuring auth reliability.
Scale Debugging with Workspaces and Features
App Builder mixes tool calls/chat for model-agnostic testing; Chat emulates host UIs (ChatGPT/Claude), compares 3 frontier models, switches Trace/Raw. Workspaces group servers for team sharing. Test Cases, Views, Skills extend control. CLI complements with server inspection, OAuth conformance/login. This workflow turns MCP hype into shippable apps by surfacing trade-offs like web's HTTPS limit versus desktop's flexibility.