Inspired by FrustrationThirty of us wrote this. One of him read it.MCP Inspector · online · no install
The MCP Inspector that runs in your browser.
↳ Test a public MCP endpoint: discover tools, resources, templates and prompts, then run a request. Compatible OAuth servers can use their own sign-in; manual tokens are available under Advanced.
No npx, no Node, no local proxy. Direct when the server allows the browser; otherwise one request at a time through our relay.
how it works
Paste a public URL. Connect.
↳ No install. Connect to a public HTTP MCP endpoint and inspect the capabilities it advertises. Compatible OAuth servers can send you through their own sign-in.
Compared to the official inspector, this page never asks you to run npx or stand up a local proxy.
- No install
No npx, no Node, no localhost:6277 proxy. Open the page and connect.
- Direct or relayed
Direct when the server sends CORS headers; otherwise a stateless relay forwards one request at a time. The badge tells you which.
- Real spec
Live tools, resources, prompts and server notifications from the actual server.
- Auto-form
Input schemas render as forms — fill, invoke, read the real JSON result.
- Shareable
Send the URL — your teammate lands on the same server. Tokens never go in the link.
- Honest errors
401 means 401. CORS-blocked means CORS-blocked. No fake “connected”.
Compared to the official inspector
Browser vs install-on-your-machine.
↳ This page runs in your browser. The official inspector is npx plus Node plus a proxy on localhost:6277.
Compatible OAuth servers can open their own sign in. Localhost servers stay on the official install — this inspector refuses private addresses.
| This page | Official @modelcontextprotocol/inspector | |
|---|---|---|
| Runs where | Your browser | npx + Node + proxy on localhost:6277 |
| Install | No install | Node required |
| Sign-in | Compatible OAuth or manual token | Whatever that install supports |
| Your machine’s localhost servers | No — the relay refuses private addresses on purpose | Yes |
What people ask about MCP inspectors.
What is an MCP server?
An MCP server is a small program that exposes tools, resources, and prompts to AI agents using the Model Context Protocol — an open spec from Anthropic. Agents like Claude, ChatGPT, and Cursor use MCP to call external systems (your database, your docs, your APIs) in a structured way without the user having to wire integrations one by one.
How do I test an MCP server online?
Paste your MCP server URL into the connect form, pick Streamable HTTP (or legacy SSE for older servers), and hit Connect. Compatible OAuth servers can redirect you through their own sign in; some require a manual token or a different client. To paste a token instead, open Advanced before you hit Connect. The inspector runs a real initialize handshake and lists advertised tools, resources, resource templates and prompts, with bounded pagination and visible discovery warnings.
Is this a free alternative to the official MCP Inspector?
For public servers, yes. The official @modelcontextprotocol/inspector needs npx, Node and a local proxy on localhost:6277; this one runs in your browser. Servers on your own machine (localhost) still need the official one — a hosted page cannot reach them, and our relay refuses private addresses on purpose.
Can I use this to inspect a Lovable MCP server?
Yes, if it is reachable on a public URL: paste it and connect. You'll see the real tools, schemas and prompts before you hand it to Claude, Cursor or another client.
Do you store my server URL or my API tokens?
Manual tokens and headers stay in page memory. OAuth credentials are stored in this tab’s session storage until disconnect. The endpoint appears in your page URL and browser history, so do not put secrets in it. When the server allows browser connections, requests go straight from your browser to it. When it doesn't, requests pass through our relay one at a time and are forwarded in memory — not stored, not logged. Only the URL and transport go in the shareable link; tokens and headers never do.
My MCP server returned a CORS error — what do I do?
For Streamable HTTP, the inspector retries automatically through its relay when a direct browser connection is blocked; the server card then shows a “via relay” badge. If the relay also fails, the server is unreachable from the public internet, redirected us, or only speaks legacy SSE.
Can I share a link with the connection pre-filled?
Yes. After connecting, copy the page URL — it includes your server URL and transport choice as query parameters. Send the link to a teammate and they can connect independently to the same endpoint. Their access, credentials and results are separate from yours.
Does this connect to my custom MCP server?
It supports public http(s) endpoints that speaks Streamable HTTP (or legacy SSE with CORS). Compatible OAuth servers can redirect you through their own sign in; some require a manual token or a different client. If it will not do that dance, paste a bearer token under Advanced before you hit Connect. Legacy SSE requires direct browser access. Local stdio servers, sampling, elicitation, subscriptions and experimental tasks are not supported here. Requests time out after 30 seconds; cancelling cannot undo an action already performed by a server.