Build, test & debug your
MCP Servers faster
The essential companion for MCP server developers. Connect your server, pick any LLM, and interactively test every tool call, prompt, and response in a real chat interface — with full activity logs.
Why developers love MCP Viewer
Building an MCP server for your company? MCP Viewer gives you a real-time, interactive way to validate every tool, prompt, and response before shipping to production.
Debug Tool Calls Live
See exactly what your MCP server receives and returns. Inspect tool call payloads, parameters, and responses in real time.
Full Activity Logs
Every request, response, and error is logged in a live activity panel. No more guessing what happened behind the scenes.
Rapid Iteration
Make changes to your MCP server, switch back to MCP Viewer, and instantly test. No restarts, no config files, no CLI gymnastics.
Test Against Any LLM
See how different models interact with your tools. Compare Claude, GPT-4, and Gemini responses to the same MCP server.
Your Keys, Your Data
API keys are stored securely in your account. We never share or access your keys for anything beyond your own requests.
Ship With Confidence
Validate every edge case before deploying. Catch malformed responses, missing parameters, and unexpected errors early.
Get started in three steps
Add your MCP server
Paste your MCP server URL into settings. Running locally? Point to localhost. Deployed? Use the production URL.
Choose your LLM
Pick from Anthropic, OpenAI, or Google. Enter your API key and select a model. Switch anytime.
Start chatting
Ask questions, trigger tool calls, and watch the full request/response cycle in the live activity log.
Built for teams building MCP servers
Whether you're a solo developer prototyping or an enterprise team shipping production MCP integrations, MCP Viewer fits into your workflow.
Local Development
Point MCP Viewer at your localhost server and iterate in real time. See tool calls and responses as you code.
QA & Validation
Test every tool your MCP server exposes. Verify parameter handling, error states, and response formats before release.
Team Demos
Show stakeholders how your MCP server works through a clean chat interface. No terminal needed.
Production Monitoring
Connect to your deployed MCP server and run smoke tests. Catch issues before your users do.
Start testing your MCP server today
Sign in with Google and connect your MCP server in under a minute. Free to use — bring your own API keys.