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json is a fast CLI tool for working with JSON. It is a single-file node.js script with no external deps (other than node.js itself). A quick taste:

$ echo '{"foo":"bar"}' | json
  "foo": "bar"

$ echo '{"foo":"bar"}' | json foo

$ echo '{"fred":{"age":42}}' | json fred.age    # '.' for property access

$ echo '{"age":10}' | json -e 'this.age++'
  "age": 11

# `json -ga` (g == group, a == array) for streaming mode
$ echo '{"latency":32,"req":"POST /widgets"}
{"latency":10,"req":"GET /ping"}
' | json -gac 'this.latency > 10' req
POST /widgets


  • pretty-printing JSON
  • natural syntax (like JS code) for extracting particular values
  • get details on JSON syntax errors (handy for config files)
  • filter input JSON (see -e and -c options)
  • fast stream processing
  • JSON validation
  • in-place file editing

See for full docs and examples as a man page.

Follow @trentmick for updates to json.


  1. Get node.

  2. npm install -g json

    Note: This used to be called 'jsontool' in the npm registry, but as of version 8.0.0 it has taken over the 'json' name. See npm Package Name below.

OR manually:

  1. Get the 'json' script and put it on your PATH somewhere (it is a single file with no external dependencies). For example:

    cd ~/bin
    curl -L > json
    chmod 755 json

You should now have "json" on your PATH:

$ json --version
json 9.0.0

WARNING for Ubuntu/Debian users: There is a current bug in Debian stable such that "apt-get install nodejs" installed a nodejs binary instead of a node binary. You'll either need to create a symlink for node, change the json command's shebang line to "#!/usr/bin/env nodejs" or use chrislea's PPA as discussed on issue #56. You can also do "apt-get install nodejs-legacy" to install symlink for node with apt.

Test suite

make test

You can also limit (somewhat) which tests are run with the TEST_ONLY envvar, e.g.:

cd test && TEST_ONLY=executable nodeunit test.js

I test against node 0.4 (less so now), 0.6, 0.8, and 0.10.


MIT (see the fine LICENSE.txt file).

Module Usage

Since v1.3.1 you can use "json" as a node.js module:

var json = require('json');

However, so far the module API isn't that useful and the CLI is the primary focus.

npm Package Name

Once upon a time, json was a different thing (see zpoley's json-command here), and this module was called jsontool in npm. As of version 8.0.0 of this module, npm install json means this tool.

If you see documentation referring to jsontool, it is most likely referring to this module.

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