9 releases (5 stable)

Uses old Rust 2015

1.1.1 Apr 13, 2021
1.0.2 Feb 9, 2021
1.0.1 Nov 3, 2020
1.0.0 Jun 29, 2020
0.6.0 Dec 30, 2017

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3,116 downloads per month
Used in 21 crates (18 directly)

MIT license

639 lines


A JSON transformer, written in Rust.

Provides fast pretty-printing and minimizing of JSON-encoded strings and streams, at the command line or within Rust programs.

Jsonxf is built for speed, and does not attempt to perform any input validation whatsoever. Valid input produces valid output, but no guarantees are offered around the detection and rejection of invalid input.

Crate docs: https://docs.rs/jsonxf/


cargo install jsonxf

Command-line Examples

Pretty-print a string to the terminal, using two spaces to indent:

jsonxf -s '{"a": {"b": 2, "c": false}}'

Pretty-print and read a JSON file, using a tab character to indent:

jsonxf -t $'\t' <foo.json | less

Minimize a file and gzip it:

jsonxf -m <foo.json | gzip -c >foo-min.json.gz

Run jsonxf -h to see all configuration options.

Rust Example

In your Cargo.toml:

jsonxf = "1.1"

In your code:

extern crate jsonxf;
let ugly_json = "{\"hello\":\"world\"}";
let pretty_json = jsonxf::pretty_print(ugly_json).unwrap();
assert_eq!(pretty_json, "{\n  \"hello\": \"world\"\n}\n");


Here are some benchmarks comparing Jsonxf 0.9's performance to several of its counterparts:

  • jq, the extremely flexible JSON processor.
  • jsonpp, a JSON pretty-printer written in Go.
  • serdexf, a trivial example using the serde_json and serde-transcode libraries. This implementation is not complete and is included for library comparison only.
  • cat is thrown in as well, for scale.

Test platform: MBP (early 2013), macOS 10.13.2, 3GHz i7, 8GB RAM.

See benchmark.rb for testing procedure.

Pretty-print test, 600MB minimized input (1M objects):

command time (s) relative time notes
cat 2.26 0.3x cat is a bad pretty-printer
jsonxf 7.76 1x
serdexf 9.33 1.2x no newlines between objects 🙁
jsonpp 25.0 3.2x
jq -M . 67.0 8.6x

Minimize test, 850MB pretty-printed input (1M objects):

command time (s) relative time notes
cat 1.45 0.2x cat is a bad minimizer
jsonxf -m 6.78 1x
serdexf -m 7.30 1.1x
jsonpp - - minimizing is not supported 😭
jq -cM . 78.0 12x

Authorship and License

Copyright 2017-2020, Pete Gamache.

Jsonxf is released under the MIT License.