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Rust Arg Parsing Benchmarks

This repo tries to assess Rust arg parsing performance.

We currently compare:

Name Style Notes
No-op N/A N/A
argh derive
bpaf Combinatoric or derive
clap_lex Imperative No help generation
clap Builder or derive Color, suggested fixes, completions
gumdrop derive
lexopt Imperative No help generation
pico-args Imperative No help generation
xflags proc-macro

See also an examination of design trade offs

Note: any non-performance comparison is meant to provide context for what you gain/lose with each crate's overhead. For a full comparison, see each parser docs


Name Overhead (release) Build (debug) Parse (release) Invalid UTF-8 Downloads Version
null 0 KiB 234ms (full)
172ms (incremental)
3ms Y - -
argh 38 KiB 3s (full)
203ms (incremental)
4ms N Download count v0.1.10
bpaf 282 KiB 965ms (full)
236ms (incremental)
5ms Y Download count v0.9.4
bpaf_derive 276 KiB 4s (full)
238ms (incremental)
5ms Y Download count v0.9.4
clap 654 KiB 3s (full)
392ms (incremental)
4ms Y Download count v4.4.0
clap-minimal 427 KiB 2s (full)
330ms (incremental)
4ms Y Download count v4.4.0
clap_derive 689 KiB 6s (full)
410ms (incremental)
4ms Y Download count v4.4.0
clap_lex 27 KiB 407ms (full)
188ms (incremental)
3ms Y Download count v0.5.1
gumdrop 37 KiB 3s (full)
198ms (incremental)
3ms N Download count v0.8.1
lexopt 34 KiB 385ms (full)
184ms (incremental)
3ms Y Download count v0.3.0
pico-args 23 KiB 384ms (full)
185ms (incremental)
3ms Y Download count v0.5.0
xflags 22 KiB 709ms (full)
179ms (incremental)
3ms Y Download count v0.3.1

System: Linux 5.4.0-124-generic (x86_64) w/ -j 8

rustc: rustc 1.72.0 (5680fa18f 2023-08-23)


  • Overhead will be lower if your application shares dependencies with your argument parsing library.

Running the Benchmarks

$ ./
$ ./

To be included, the crate needs meet one of the following criteria:

  • 10k+ recent downloads
  • Unique API design

Special Thanks