MCP SSE Demo: Push Limits, Solve Bottlenecks with Bun Runtime

Push MCP SSE server boundaries with Bun Runtime—stress-test limits, pinpoint bottlenecks, and unlock scalable solutions for real-world workloads.

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About MCP SSE Demo

What is MCP SSE Demo: Push Limits, Solve Bottlenecks with Bun Runtime?

This demo showcases how a Server-Sent Events (SSE) server behaves differently when using the Bun runtime versus Node.js. The goal is to identify performance bottlenecks specific to Bun by reproducing scenarios where SSE connections hang or fail, while Node.js handles the same workload smoothly. For example, you might notice pending requests stuck indefinitely with Bun but see instant responses with Node.js.

How to Use MCP SSE Demo: Push Limits, Solve Bottlenecks with Bun Runtime?

Start by installing dependencies via Bun. Launch the MCP inspector tool at http://localhost:5173, then configure it to target your SSE endpoint. Run the server first with Bun and observe connection issues in the browser’s network tab. Switch to Node.js by restarting the server, and watch the same setup work flawlessly. This side-by-side test helps pinpoint runtime-specific quirks.

MCP SSE Demo Features

Key Features of MCP SSE Demo: Push Limits, Solve Bottlenecks with Bun Runtime?

Real-time visibility into connection lifecycle via browser dev tools
Direct comparison of Bun vs. Node.js SSE handling
Log analysis capabilities to trace where requests stall
Reproducible setup for testing edge cases like high message rates

Use Cases of MCP SSE Demo: Push Limits, Solve Bottlenecks with Bun Runtime?

Developers can use this demo to:

Validate Bun’s readiness for production SSE workloads
Diagnose connection timeouts in real-time applications
Test fallback strategies when Bun hits performance limits
Compare runtime efficiency under varying message payloads

MCP SSE Demo FAQ

FAQ from MCP SSE Demo: Push Limits, Solve Bottlenecks with Bun Runtime?

Why does Bun fail here but Node.js works?: Bun’s event loop or HTTP parser might handle SSE streams differently, especially under specific load conditions. Node.js’s mature HTTP module often provides more predictable results.
Can this demo help optimize my app?: Yes! By reproducing failures, you can isolate issues to the runtime itself and implement workarounds like message throttling or using Node.js for critical SSE paths.
Is this only for Bun developers?: No—anyone testing SSE reliability benefits. It’s a valuable benchmarking tool regardless of your chosen runtime.

Content

MCP SSE demo

reproducible demo that shows an MCP SSE server fails using the bun runtime but succeeds using nodejs.

steps

install dependencies

# or npm | yarn | pnpm install, same effect
bun install

run the MCP inspector

npm run inspect

open the inspector http://localhost:5173
select SSE as the transport and enter http://localhost:3500/sse as the url
open dev tools network tab to inspect traffic
in another terminal tab / session run the server using bun

npm run start:bun

try to connect to the server using the inspector, observe the network (pending SSE connection), server and inspector logs
kill the bun server then run the server using nodejs

npm run start:node

try to connect to the server using the inspector, observe the network (successful SSE connection and message posting), server and inspector logs