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 |
| 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:
| Name | Overhead (release) | Build (debug) | Parse (release) | Downloads | Version |
|---|---|---|---|---|---|
| null | 0 KiB | 249ms | 3ms | - | - |
| grmtools | 2,610 KiB | 11s | 164ms |  | v0.13.10 |
| chumsky | 150 KiB | 4s | 32ms |  | v0.10.1 |
| combine | 181 KiB | 4s | 53ms |  | v3.8.1 |
| lalrpop | 1,523 KiB | 11s | 37ms |  | v0.22.2 |
| logos | 90 KiB | 4s | 21ms |  | v0.15.0 |
| nom | 98 KiB | 3s | 65ms |  | v8.0.0 |
| parol | 492 KiB | 9s | 174ms |  | v4.1.0 |
| peg | 80 KiB | 2s | 23ms |  | v0.8.5 |
| pest | 130 KiB | 5s | 61ms |  | v2.8.1 |
| serde_json | 59 KiB | 3s | 14ms |  | v1.0.142 |
| winnow | 75 KiB | 2s | 28ms |  | v0.7.12 |
| yap | 61 KiB | 527ms | 33ms |  | v0.12.0 |
System: Linux 6.8.0-62-generic (x86_64), rustc 1.89.0 (29483883e 2025-08-04) 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)
$ ./bench.py $ ./format.py