HTTP Server Benchmark Report

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

Fastest

C (h2o)

411,965 req/s (libh2o-evloop)

Runner-up

Rust

316,506 req/s (axum + tokio)

Lowest p99

C (h2o)

0.009ms

Implementations

15

languages tested

Peak Throughput Rankings

#	Language	Framework	Peak req/s	@ conns	Avg (ms)	p99 (ms)
1	C (h2o)	libh2o-evloop	411,965	8	0.017	0.028
2	Rust	axum + tokio	316,506	8	0.026	0.039
3	Java (Vert.x)	Vert.x	277,621	8	0.099	2.47
4	Bun	Bun.serve()	230,697	8	0.036	0.130
5	Scheme	pico + io_uring	222,365	16	0.071	0.110
6	Deno	Deno.serve()	208,723	8	0.039	0.086
7	Go	net/http (stdlib)	178,119	8	0.047	0.137
8	Node.js	http (stdlib)	141,993	8	0.063	0.126
9	Gleam	mist + gleam_otp	88,743	2	0.023	0.033
10	Common Lisp	Hunchentoot	48,918	8	0.155	0.250
11	FastAPI	uvicorn	47,968	64	1.33	1.75
12	Java (Loom)	HttpServer + virtual threads	44,662	256	11.43	42.27
13	Ruby	Falcon (async)	32,800	16	0.486	0.771
14	Racket	web-server (stdlib)	30,849	16	0.733	1.89
15	Flask	gunicorn (1 worker)	11,956	8	0.660	0.812

Scaling Data

C (h2o) libh2o-evloop

Conns	Req/s	Avg (ms)	p99 (ms)
1	144,672	0.007	0.009
2	342,465	0.006	0.009
4	391,204	0.010	0.014
8	411,965	0.017	0.028
16	397,669	0.079	1.81
32	379,993	0.084	0.163
64	385,252	0.162	0.317
128	370,107	0.316	0.578
256	370,045	0.670	0.87

Rust axum + tokio

Conns	Req/s	Avg (ms)	p99 (ms)
1	126,194	0.010	0.026
2	278,756	0.009	0.014
4	308,841	0.014	0.029
8	316,506	0.026	0.039
16	298,983	0.056	0.106
32	294,922	0.109	0.155
64	296,626	0.212	0.283
128	284,861	0.410	0.503
256	279,636	0.836	1.03

Java (Vert.x) Vert.x

Conns	Req/s	Avg (ms)	p99 (ms)
1	126,309	0.055	1.82
2	241,491	0.092	2.52
4	265,360	0.103	2.59
8	277,621	0.099	2.47
16	269,709	0.140	2.59
32	274,920	0.177	2.41
64	266,481	0.319	2.91
128	259,299	0.558	3.69
256	246,170	1.07	4.56

Bun Bun.serve()

Conns	Req/s	Avg (ms)	p99 (ms)
1	119,358	0.010	0.082
2	200,261	0.012	0.098
4	222,170	0.019	0.094
8	230,697	0.036	0.130
16	226,257	0.073	0.216
32	226,297	0.142	0.317
64	230,107	0.284	0.445
128	222,555	0.540	0.810
256	220,414	1.09	1.41

Scheme pico + io_uring

Conns	Req/s	Avg (ms)	p99 (ms)
1	108,397	0.011	0.027
2	161,105	0.014	0.032
4	209,966	0.019	0.037
8	215,618	0.036	0.061
16	222,365	0.071	0.110
32	221,382	0.143	0.211
64	212,670	0.294	0.412
128	211,276	0.550	0.687
256	204,960	1.13	1.39

Deno Deno.serve()

Conns	Req/s	Avg (ms)	p99 (ms)
1	91,323	0.012	0.038
2	159,876	0.014	0.046
4	175,672	0.024	0.071
8	208,723	0.039	0.086
16	203,272	0.079	0.142
32	198,107	0.162	0.253
64	190,716	0.340	0.495
128	184,191	0.642	0.88
256	185,278	1.26	1.67

Go net/http (stdlib)

Conns	Req/s	Avg (ms)	p99 (ms)
1	108,364	0.010	0.032
2	173,898	0.013	0.054
4	177,225	0.025	0.085
8	178,119	0.047	0.137
16	170,107	0.098	0.258
32	167,042	0.195	0.472
64	165,263	0.387	0.88
128	159,520	0.744	1.62
256	153,473	1.54	2.76

Node.js http (stdlib)

Conns	Req/s	Avg (ms)	p99 (ms)
1	109,249	0.014	0.047
2	136,410	0.021	0.061
4	138,715	0.037	0.096
8	141,993	0.063	0.126
16	141,028	0.121	0.206
32	139,651	0.239	0.371
64	135,504	0.504	0.722
128	134,333	1.00	1.51
256	131,666	2.63	9.66

Gleam mist + gleam_otp

Conns	Req/s	Avg (ms)	p99 (ms)
1	59,027	0.018	0.045
2	88,743	0.023	0.033
4	85,989	0.048	0.079
8	86,758	0.092	0.143
16	86,639	0.184	0.236
32	85,734	0.373	0.467
64	84,955	0.756	0.97
128	82,956	1.43	1.75
256	83,257	3.05	3.36

Common Lisp Hunchentoot

Conns	Req/s	Avg (ms)	p99 (ms)
1	32,939	0.022	0.045
2	48,770	0.034	0.092
4	48,789	0.075	0.158
8	48,918	0.155	0.250
16	48,429	0.322	0.512
32	47,993	0.651	0.811
64	47,893	4.10	55.14
128	25,182	37.95	615.11
256	32,274	28.74	615.62

FastAPI uvicorn

Conns	Req/s	Avg (ms)	p99 (ms)
1	36,632	0.028	0.038
2	43,534	0.046	0.060
4	43,501	0.091	0.118
8	44,993	0.177	0.249
16	46,746	0.341	0.613
32	46,223	0.693	0.809
64	47,968	1.33	1.75
128	46,845	2.70	4.77
256	47,564	7.98	130.03

Java (Loom) HttpServer + virtual threads

Conns	Req/s	Avg (ms)	p99 (ms)
1	24	41.04	44.08
2	49	40.99	43.91
4	97	40.98	43.03
8	195	41.04	44.00
16	388	41.07	44.56
32	777	41.12	44.97
64	1,517	41.16	44.05
128	2,802	41.15	44.96
256	44,662	11.43	42.27

Ruby Falcon (async)

Conns	Req/s	Avg (ms)	p99 (ms)
1	29,438	0.038	0.226
2	30,535	0.069	0.291
4	31,492	0.130	0.384
8	32,003	0.250	0.522
16	32,800	0.486	0.771
32	32,732	0.97	1.32
64	31,033	2.07	2.41
128	29,138	4.13	4.43
256	28,029	11.98	164.18

Racket web-server (stdlib)

Conns	Req/s	Avg (ms)	p99 (ms)
1	28,041	0.265	1.03
2	29,858	0.367	1.66
4	28,954	0.392	1.61
8	30,489	0.511	1.66
16	30,849	0.733	1.89
32	28,207	1.39	2.92
64	27,331	2.54	5.69
128	25,305	4.88	9.91
256	23,543	10.12	20.91

Flask gunicorn (1 worker)

Conns	Req/s	Avg (ms)	p99 (ms)
1	11,774	0.077	0.153
2	11,772	0.162	0.268
4	11,917	0.327	0.448
8	11,956	0.660	0.812
16	11,939	1.33	1.56
32	11,905	2.68	2.95
64	11,855	5.30	6.08
128	11,882	9.79	10.76
256	11,116	20.86	22.04

Top 5 by Concurrency Level

Connections	1st	2nd	3rd	4th	5th
1	1C (h2o)144,672 req/s	2Java (Vert.x)126,309 req/s	3Rust126,194 req/s	4Bun119,358 req/s	5Node.js109,249 req/s
2	1C (h2o)342,465 req/s	2Rust278,756 req/s	3Java (Vert.x)241,491 req/s	4Bun200,261 req/s	5Go173,898 req/s
4	1C (h2o)391,204 req/s	2Rust308,841 req/s	3Java (Vert.x)265,360 req/s	4Bun222,170 req/s	5Scheme209,966 req/s
8	1C (h2o)411,965 req/s	2Rust316,506 req/s	3Java (Vert.x)277,621 req/s	4Bun230,697 req/s	5Scheme215,618 req/s
16	1C (h2o)397,669 req/s	2Rust298,983 req/s	3Java (Vert.x)269,709 req/s	4Bun226,257 req/s	5Scheme222,365 req/s
32	1C (h2o)379,993 req/s	2Rust294,922 req/s	3Java (Vert.x)274,920 req/s	4Bun226,297 req/s	5Scheme221,382 req/s
64	1C (h2o)385,252 req/s	2Rust296,626 req/s	3Java (Vert.x)266,481 req/s	4Bun230,107 req/s	5Scheme212,670 req/s
128	1C (h2o)370,107 req/s	2Rust284,861 req/s	3Java (Vert.x)259,299 req/s	4Bun222,555 req/s	5Scheme211,276 req/s
256	1C (h2o)370,045 req/s	2Rust279,636 req/s	3Java (Vert.x)246,170 req/s	4Bun220,414 req/s	5Scheme204,960 req/s