Express 4 vs Express 5 Performance Benchmark

Express is one of the most popular Node.js web frameworks on npm. There are plenty of benchmarks comparing Express to alternative frameworks, but we couldn’t find a clean comparison of Express 4 vs Express 5, so we decided to test it ourselves.

This Express 4 vs Express 5 benchmark compares requests per second (rps) across:

Ping (GET /ping)

This is the simplest possible case. A single route returning a small response with no application-level logic.

Middleware x50 (GET /ping)

This test introduces 50 synchronous middleware functions before reaching the handler.

JSON body ~50 KB (POST /json)

This test measures JSON parsing and request body handling using a payload of approximately 50 KB.

Response payload 100 KB (GET /payload)

This scenario measures throughput when sending a larger response body.

How the Tests Were Performed

We measured each test 5 times and averaged the result. We let the Mac cool down for a full hour before running the benchmark again.

Conclusion

Across all tested Node versions and scenarios, Express 5 is consistently slower than Express 4 in raw throughput. The difference is not dramatic, but it is noticeable and repeatable, especially on lightweight routes and middleware-heavy setups.

For larger payloads and JSON-heavy endpoints, the gap narrows and in some cases nearly disappears. But if your workload is dominated by small responses or deep middleware chains, Express 4 still delivers higher requests per second.

Upgrading to Express 5 is therefore a trade off. You gain newer behavior and long-term maintenance, but at the cost of lower peak throughput compared to Express 4.