MCP Transport: stdio vs SSE — When to Use Each

Observation

stdio stays underrated because it feels less “web-native,” but it is often the simpler and more reliable transport when the client and server already live in the same controlled runtime.

Rule of thumb

• use stdio for local or tightly managed tool execution
• use SSE when network reachability or remote hosting is the primary concern

Practical note

Teams often choose SSE too early because it looks more extensible. In practice, the local debugging path gets worse.