Rust Parsing Benchmarks

This repo tries to assess Rust parsing performance.

crate	parser type	action code	integration	input type	precedence	parameterized rules	streaming input
chumsky	combinators	in source	library	&str, &[u8], custom	pratt	Yes	Yes
combine	combinators	in source	library	&str	?	?	?
grmtools	CFG	in grammar	library	?	?	?	?
lalrpop	LR(1)	in grammar	build script	&str	none	Yes	No
lelwel	LL(1)	in source	build script	&str	pratt	No	No
logos	lexer	in source	proc macro	&str, &[u8]	?	?	?
nom	combinators	in source	library	&str, &[u8], custom	pratt	Yes	Yes
parol	LL(k)/LALR(1)	in source	build script	&str	climbing	No	No
peg	PEG	in grammar	proc macro (block)	&str, &[T], custom	climbing	Yes	No
pest	PEG	external	proc macro (file)	&str	climbing	No	No
winnow	combinators	in source	library	&str, &[T], custom	none	Yes	Yes
yap	combinators	in source	library	&str, &[T], custom	none	Yes	?

Formerly, we compared:

• pom: lack of notoriety

Results

Name	Overhead (release)	Build (debug)	Parse (release)	Downloads	Version
null	0 KiB	164ms	2ms	-	-
grmtools	2,612 KiB	10s	182ms		v0.14.1
chumsky	161 KiB	5s	47ms		v0.12.0
combine	175 KiB	4s	53ms		v3.8.1
lalrpop	1,523 KiB	12s	40ms		v0.23.1
lelwel	175 KiB	7s	33ms		v0.10.4
logos	71 KiB	6s	22ms		v0.16.1
nom	88 KiB	3s	68ms		v8.0.0
parol	480 KiB	9s	184ms		v4.4.0
peg	77 KiB	2s	29ms		v0.8.5
pest	119 KiB	3s	62ms		v2.8.6
serde_json	57 KiB	3s	18ms		v1.0.149
winnow	67 KiB	1s	27ms		v1.0.1
yap	60 KiB	420ms	40ms		v0.12.0

System: Linux 6.17.9-76061709-generic (x86_64), rustc 1.94.1 (e408947bf 2026-03-25) w/ -j 8

Note:

• For more "Parse (release)" comparisons, see parser_benchmarks
• Parsers have not been validated and might have differing levels of quality (#5)

Running the Benchmarks

$ ./bench.py
$ ./format.py