benchmark-nestjs

The objective here was to create a simple comparison between Express and Fastify platform on a Nestjs application.

On the documentation, it's said:

[...] fastify is much faster than Express, achieving almost two times better benchmarks results.

So I'd like to confirm that findings.

This repository is a standard project with a simple route GET / that returns the message Hello World!.

Running the server

To start the Express server we use:

nest start

To start the Fastify server we use:

nest start --config=nest-cli.fastify.json

Apache benchmark was used to simulate parallel requests and measure de perceived performance of the server with this command:

ab -k -c 200 -n 20000 http://localhost:3000/

To understand the performance of the Node process, I used an additional option on the command line:

nest start -e 'node --prof --no-logfile-per-isolate'

for Express and:

nest start --config=nest-cli.fastify.json -e 'node --prof --no-logfile-per-isolate'

for Fastify. Each execution created a v8.log file that I processed with:

node --prof-process v8.log > express/fastify.txt

For more information about this, read this article.

These are the results on a Intel(R) Core(TM) i7-7500U CPU @ 2.70GHz:

Measure (unit)	Express	Fastify	Δ
Time taken for tests (seconds)	4.544	1.676	-63%
Total transferred (bytes)	4780000	3520000	-26%
Requests per second (#/sec)	4401.73	11935.64	+171%
Time per request (ms)	45.437	16.757	-63%
Time per request (all) (ms)	0.227	0.084	-63%
Transfer rate (Kbytes/second)	1027.36	2051.44	+99%

The profiling revealed that Express has some hotspots specially with dynamic functions compilation and RegExp usage (or abuse).