jsonwidget is a general-purpose JSON validation and manipulation library. This library provides the following functions for applications:

  • Validation of JSON-compatible data against a schema
  • Automatic generation of a schema from JSON-compatible data
  • Construction of a curses-based tree data editing user interface from a schema
  • Construction of a Javascript-based web tree data editing user interface from a schema
  • Simple WSGI server to serve the web user interface, and validate and store result of editing with the web user interface

Though jsonwidget is optimized for working with JSON, it is useful for providing editing capability for any JSON-compatible data structure.

Included utilities

The following utilities are included with jsonwidget:

  • jsonedit - A terminal-based application (like you would use via SSH or local terminal on Linux and Mac). It's based on urwid, an excellent Python-based library for building terminal-based user interfaces.
  • csvedit - A variation on jsonedit that allows editing of .csv/tsv files.
  • jsonaddress - an example JSON address book editor
  • jwc - a command line utility with the following functions:
    • editserver - launch a web server to edit a json file from a browser
    • json2yaml - convert a json file to yaml with comments pulled from schema (also yaml2json to go back)
    • schemagen - create a schema from an example json file
    • validate - validate a JSON file against a schema

Using the jsonwidget library

A good example (as of this writing) of how to use jsonwidget as a library is "yamledit" in the examples directory, which demonstrates where to hook in file parsers for formats other than JSON.

Schema language

There are two JSON schema languages that are supported by jsonwidget:

  • Version 2 is a subset of the JSON schema format documented here:

    Version 2 is not fully supported by jsonwidget at this time. The Python portions of the library support v1 and v2 equally well (more or less), but the Javascript portion only supports v1.


Most of jsonwidget is licensed under the BSD license. Portions were derived from urwid, and thus are LGPL. Copies of both licenses can be found in the docs directory.

Unless otherwise indicated, all files in this distribution are under the following license (BSD).

Reporting Bugs

Please send bug reports to me (Rob Lanphier <>), or file a bug at the bug tracker


The latest source can be found at Bitbucket.