Use Insomnia to connect external Model Context Protocol (MCP) Servers to access AI-ready tools, prompts, and resource. An MCP Client defines this connection and stores authentication and configuration details.
MCP clients in Insomnia
Uses:
Insomnia
Related Documentation
Minimum Version
Insomnia - 12.0
Related Resources
Overview
An MCP Server is an HTTP JSON-RPC endpoint that advertises callable operations:
- Tools – Executable server functions
- Prompts – Reusable prompt templates
- Resources – Structured contextual data
The Insomnia MCP Client discovers these elements, which enables you to invoke, query, or test them directly in the app. Each workspace can include multiple MCP Clients.
Create an MCP client
To create a new MCP Client:
- From the left pane of the Insomnia application, click MCP Clients.
- In the Name box, type a name for the MCP Client.
- Click Create.
- In the MCP Server URL box, enter the full endpoint of your target server. For example:
-
https://mcp.deepwiki.com/mcp(DeepWiki)
-
- To connect your MCP client to the MCP server, click Connect.
- (Optional) If the server requires authentication, follow the MCP Auth Flow to sign in or provide a token.
- Once connected, in the left pane, confirm that discovered tools, prompts, and resources appear.
Explore the interface
The MCP Client interface in Insomnia provides multiple panes that display operations, parameters, and runtime details from connected MCP Servers.
Use these panes to inspect discovered endpoints, configure request parameters, and validate outputs in real time.
|
Tab |
Description |
|---|---|
| Params | Define or edit input parameters for the selected MCP operation. Each field corresponds to the parameters advertised by the server’s schema. |
| Auth | Configure authentication information. |
| Headers | Add or override request headers before sending a call to the server. Use for testing custom content types or authorization headers. |
| Roots | Displays available endpoints or callable tools exposed by the connected MCP server. Use to select a route to load its parameters into the Params tab. |
| Events | Displays real-time server events such as discovery updates or authentication state changes during the MCP session. |
| Notifications | Lists informational or error messages returned by the MCP Server or Insomnia runtime. For example, sync success or OAuth errors. |
| Headers | Shows response headers returned from the MCP Server, including status and content type. Use to verify that the response matches expected headers. |
| Console | Displays detailed logs and operation results. Use this tab to inspect raw request and response payloads when troubleshooting MCP interactions. |
MCP Authentication
When you connect to an MCP Server that requires authentication, Insomnia follows the MCP Auth Flow:
- If the server responds with 401 Unauthorized and includes valid metadata,
Insomnia automatically discovers the associated OAuth authorization server. - If your current auth method is OAuth 2.0 > MCP Auth Flow and it’s enabled,
Insomnia requests a token through that flow. - If it’s not selected, Insomnia prompts you to switch to the discovered auth flow.
Confirm to proceed or cancel to remain on your current method.
If the authorization server does not support Dynamic Client Registration, you can:
- Use a Personal Access Token (PAT), for example GitHub Copilot MCP Server.
- Register your own OAuth application, then enter the Client ID and Secret in Insomnia.
FAQs
What happens when authentication fails?
If the MCP Server responds with 401 Unauthorized, Insomnia automatically looks for OAuth metadata and applies the MCP Auth Flow.
If no OAuth metadata is provided, you can connect manually using a Personal Access Token (PAT) or a registered OAuth application.
How do I refresh operations from the server?
- From MCP Servers, in the left pane, click Resync.
Insomnia refreshes all tools, prompts, and resources from the connected MCP Server.
How do I refresh operations from the server?
- From MCP Servers in the left pane, click Resync.
Insomnia refreshes all Tools, Prompts, and Resources from the connected MCP Server.
Why do I see 401 Unauthorized during MCP discovery?
Many MCP Servers expect the client to discover their authorization server first. A typical pattern is: client contacts the server > server returns 401 with metadata > client follows metadata to obtain OAuth endpoints. Some MCP Servers do not support Dynamic Client Registration (DCR); in this case, use a pre-registered client or PAT instead.
Why can’t Insomnia connect to my MCP Server?
The MCP Server must support the HTTP JSON-RPC transport protocol. If a connection fails or no resources are discovered, confirm that your server exposes a valid MCP endpoint and is online. If the server is temporarily unreachable, Insomnia displays cached resources until the next successful sync.
Can I use a Personal Access Token (PAT) instead of OAuth?
Yes. Select Auth > Bearer Token and enter your PAT in the Token field.
Why doesn’t my browser open during OAuth sign-in?
The MCP Auth Flow uses your system’s default browser. Ensure that Insomnia can open URLs using your system browser. The MCP Auth Flow only supports browser-based OAuth.
Why is MCP Auth Flow not listed under OAuth 2.0?
The MCP Server’s metadata may not include a valid authorization endpoint. Use a Personal Access Token (PAT) or Basic Auth instead.