HTTP Server Benchmark Report

Counter application — single-threaded, 10s per concurrency level, wrk load generator

Fastest

Rust

407,045 req/s (axum + tokio)

Runner-up

letloop

305,820 req/s (flow2 + io_uring)

Lowest p99

Rust

0.014ms

Implementations

languages tested

Peak Throughput Rankings

#	Language	Framework	Peak req/s	@ conns	Avg (ms)	p99 (ms)
1	Rust	axum + tokio	407,045	8	0.019	0.029
2	letloop	flow2 + io_uring	305,820	16	0.052	0.083
3	Bun (canary)	Bun.serve() (canary, Rust)	302,935	32	0.106	0.189
4	Bun	Bun.serve()	294,188	8	0.028	0.093
5	Node.js	http (stdlib)	192,297	8	0.044	0.079
6	FastAPI	uvicorn	36,096	64	1.77	1.80

Language

Framework

Peak req/s

@ conns

Avg (ms)

p99 (ms)

Rust

axum + tokio

407,045

0.019

0.029

letloop

flow2 + io_uring

305,820

0.052

0.083

Bun (canary)

Bun.serve() (canary, Rust)

302,935

0.106

0.189

Bun

Bun.serve()

294,188

0.028

0.093

Node.js

http (stdlib)

192,297

0.044

0.079

FastAPI

uvicorn

36,096

1.77

1.80

Scaling Data

Rust axum + tokio

Conns	Req/s	Avg (ms)	p99 (ms)
1	163,701	0.012	0.019
2	348,020	0.007	0.014
4	393,952	0.011	0.019
8	407,045	0.019	0.029
16	389,557	0.042	0.058
32	377,997	0.084	0.106
64	372,498	0.168	0.188
128	358,274	0.325	0.394
256	346,981	0.673	0.87

letloop flow2 + io_uring

Conns	Req/s	Avg (ms)	p99 (ms)
1	131,731	0.014	0.033
2	212,046	0.012	0.023
4	232,357	0.018	0.033
8	244,493	0.033	0.054
16	305,820	0.052	0.083
32	300,097	0.105	0.155
64	288,206	0.217	0.319
128	272,609	0.427	0.617
256	233,948	1.00	1.79

Bun (canary) Bun.serve() (canary, Rust)

Conns	Req/s	Avg (ms)	p99 (ms)
1	169,565	0.008	0.035
2	231,679	0.011	0.045
4	267,334	0.017	0.057
8	288,192	0.029	0.074
16	300,401	0.054	0.109
32	302,935	0.106	0.189
64	300,827	0.248	0.311
128	288,458	0.416	0.580
256	291,289	0.837	1.04

Bun Bun.serve()

Conns	Req/s	Avg (ms)	p99 (ms)
1	150,925	0.011	0.067
2	256,446	0.009	0.064
4	284,969	0.016	0.072
8	294,188	0.028	0.093
16	292,421	0.056	0.145
32	291,609	0.110	0.217
64	288,503	0.228	0.364
128	285,737	0.424	0.588
256	277,067	0.86	1.15

Node.js http (stdlib)

Conns	Req/s	Avg (ms)	p99 (ms)
1	132,896	0.011	0.031
2	184,737	0.014	0.040
4	187,992	0.027	0.054
8	192,297	0.044	0.079
16	188,335	0.089	0.131
32	180,902	0.182	0.235
64	175,701	0.387	0.457
128	164,915	0.779	0.90
256	160,034	2.01	2.05

FastAPI uvicorn

Conns	Req/s	Avg (ms)	p99 (ms)
1	33,081	0.030	0.040
2	33,145	0.064	0.103
4	33,964	0.119	0.211
8	34,776	0.232	0.389
16	35,048	0.456	0.482
32	35,675	0.90	0.94
64	36,096	1.77	1.80
128	35,808	3.59	3.48
256	32,571	13.17	273.48

Top 5 by Concurrency Level

Connections	1st	2nd	3rd	4th	5th
1	1Bun (canary)169,565 req/s	2Rust163,701 req/s	3Bun150,925 req/s	4Node.js132,896 req/s	5letloop131,731 req/s
2	1Rust348,020 req/s	2Bun256,446 req/s	3Bun (canary)231,679 req/s	4letloop212,046 req/s	5Node.js184,737 req/s
4	1Rust393,952 req/s	2Bun284,969 req/s	3Bun (canary)267,334 req/s	4letloop232,357 req/s	5Node.js187,992 req/s
8	1Rust407,045 req/s	2Bun294,188 req/s	3Bun (canary)288,192 req/s	4letloop244,493 req/s	5Node.js192,297 req/s
16	1Rust389,557 req/s	2letloop305,820 req/s	3Bun (canary)300,401 req/s	4Bun292,421 req/s	5Node.js188,335 req/s
32	1Rust377,997 req/s	2Bun (canary)302,935 req/s	3letloop300,097 req/s	4Bun291,609 req/s	5Node.js180,902 req/s
64	1Rust372,498 req/s	2Bun (canary)300,827 req/s	3Bun288,503 req/s	4letloop288,206 req/s	5Node.js175,701 req/s
128	1Rust358,274 req/s	2Bun (canary)288,458 req/s	3Bun285,737 req/s	4letloop272,609 req/s	5Node.js164,915 req/s
256	1Rust346,981 req/s	2Bun (canary)291,289 req/s	3Bun277,067 req/s	4letloop233,948 req/s	5Node.js160,034 req/s

Connections

1st

2nd

3rd

4th

5th

1Bun (canary)169,565 req/s

2Rust163,701 req/s

3Bun150,925 req/s

4Node.js132,896 req/s

5letloop131,731 req/s

1Rust348,020 req/s

2Bun256,446 req/s

3Bun (canary)231,679 req/s

4letloop212,046 req/s

5Node.js184,737 req/s

1Rust393,952 req/s

2Bun284,969 req/s

3Bun (canary)267,334 req/s

4letloop232,357 req/s

5Node.js187,992 req/s

1Rust407,045 req/s

2Bun294,188 req/s

3Bun (canary)288,192 req/s

4letloop244,493 req/s

5Node.js192,297 req/s

1Rust389,557 req/s

2letloop305,820 req/s

3Bun (canary)300,401 req/s

4Bun292,421 req/s

5Node.js188,335 req/s

1Rust377,997 req/s

2Bun (canary)302,935 req/s

3letloop300,097 req/s

4Bun291,609 req/s

5Node.js180,902 req/s

1Rust372,498 req/s

2Bun (canary)300,827 req/s

3Bun288,503 req/s

4letloop288,206 req/s

5Node.js175,701 req/s

128

1Rust358,274 req/s

2Bun (canary)288,458 req/s

3Bun285,737 req/s

4letloop272,609 req/s

5Node.js164,915 req/s

256

1Rust346,981 req/s

2Bun (canary)291,289 req/s

3Bun277,067 req/s

4letloop233,948 req/s

5Node.js160,034 req/s