DENKOPS

Free tools · MCP server checker

MCP server checker.

Paste the URL of a remote MCP server. The checker connects the way Claude, ChatGPT and other clients do: it sends initialize, lists the tools, and when the server asks for sign-in it follows the OAuth discovery chain step by step. You see exactly which step breaks.

Public HTTPS URLs only. We send standard MCP requests, store nothing and never send credentials.

What the checker tests

  1. Reachability. The URL is public HTTPS and answers within a few seconds.
  2. Initialize. A JSON-RPC initialize request gets a valid response with a protocol version, server info and capabilities, as JSON or as a Server-Sent Events stream.
  3. Tools. tools/list returns tools with names, descriptions and an object inputSchema.
  4. The 401 challenge. If the server requires sign-in, it answers 401 with a WWW-Authenticate header that points to its protected resource metadata.
  5. Protected resource metadata (RFC 9728) lists at least one authorization server.
  6. Authorization server metadata (RFC 8414 or OpenID discovery) has authorization and token endpoints, supports PKCE with S256, and offers a way for clients to register: dynamic client registration or client ID metadata documents.
  7. CORS. Whether browser-based clients and inspectors may call the server.

Reading the result

Green means a client will get past that step. Amber is a warning: it works for some clients, not all. Red stops a client. Each line says what was expected and what the server sent.

Fixing OAuth by hand is the most common reason servers fail here. On DenkOps, "connector": true runs the whole chain for you, see OAuth for MCP servers.

FAQ

Is my MCP server URL stored?

No. The checker runs the requests and returns the result. Nothing is saved, and no credentials or tokens are sent.

Why does my server pass here but fail in Claude?

Claude also needs the sign-in flow itself to complete: your authorization server must accept Claude's redirect URL and issue a token for your server's URL. The checker verifies discovery and registration, not a real sign-in.

Can it check servers on localhost?

No. The checker runs on our servers and only reaches public HTTPS URLs. For local servers, use the MCP Inspector.

Try it free → MCP server hosting

Free: 1 project, no credit card. 5 project slots €39/month, €5 per extra slot.

View service status →Managed EU infrastructure