David J. Oswald > JSON-Tiny-0.49 > JSON::Tiny



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Module Version: 0.49   Source   Latest Release: JSON-Tiny-0.53


JSON::Tiny - Minimalistic JSON. No dependencies.


  use JSON::Tiny qw(decode_json encode_json);

  # Encode and decode JSON (die on errors)
  my $bytes = encode_json({foo => [1, 2], bar => 'hello!', baz => \1});
  my $hash  = decode_json($bytes);

  # Handle errors
  my $json = JSON::Tiny->new;
  my $hash = $json->decode($bytes);
  my $err  = $json->error;
  say $err ? "Error: $err" : $hash->{message};


JSON::Tiny is a minimalistic standalone adaptation of Mojo::JSON, from the Mojolicious framework. It is a single-source-file module with 315 lines of code and core-only dependencies.

Features include transparent Unicode support, speed, small memory footprint, and a minimal code base ideal for bundling or inlining. Along with Mojo:JSON, it is possibly the fastest pure-Perl implementation of RFC 7159.

JSON::Tiny supports normal Perl data types like scalar, array reference, hash reference, and will try to call the TO_JSON method on blessed references, or stringify them if it doesn't exist.

Differentiating between strings and numbers in Perl is hard; depending on how it has been used, a scalar can be both at the same time. The string value gets precedence unless both representations are equivalent.

  [1, -2, 3]     -> [1, -2, 3]
  {"foo": "bar"} -> {foo => 'bar'}

Literal names will be translated to and from JSON::Tiny constants or a similar native Perl value.

  true  -> JSON::Tiny->true
  false -> JSON::Tiny->false
  null  -> undef

In addition scalar references will be used to generate Booleans, based on if their values are true or false.

  \1 => true
  \0 => false

The two Unicode whitespace characters u2028 and u2029 will always be escaped to make JSONP easier.


JSON::Tiny implements the following functions, which can be imported individually.


  my $value = decode_json($bytes);

Decode JSON to Perl value and die if decoding fails.


  my $bytes = encode_json({foo => 'bar'});

Encode Perl value to JSON.


  my $bytes = j([1, 2, 3]);
  my $bytes = j({foo => 'bar'});
  my $value = j($bytes);

Encode Perl data structure (which may only be an array reference or hash reference) or decode JSON. Dies if decoding fails.


JSON::Tiny implements the following attributes.


  my $err = $json->error;
  $json   = $json->error('Parser error');

Parser errors.


JSON::Tiny implements the following methods.


  my $json = JSON::Tiny->new;

Instantiate a JSON::Tiny object.


  my $value  = $json->decode($bytes);

Decode JSON to Perl value and set "error" if decoding failed.


  my $bytes = $json->encode({foo => 'bar'});

Encode Perl value to JSON.


  my $false = JSON::Tiny->false;
  my $false = $json->false;

False value, used because Perl has no native equivalent.


  my $true = JSON::Tiny->true;
  my $true = $json->true;

True value, used because Perl has no native equivalent.

More on Booleans

A reference to a scalar (even if blessed) will also be encoded as a Boolean value unless it has a TO_JSON method.

  my $json = $j->encode( { b => \1, a => \0 } ); # {"b":true,"a":false}

Boolean false and true values returned when JSON is decoded are JSON::Tiny::_Bool objects with stringification and numeric overloading.

As an advanced option, users requiring a plain old literal 0 or 1, may set $JSON::Tiny::FALSE = 0; and $JSON::Tiny::TRUE = 1;. Any value, including blessed references will work. The setting must be made prior to calling a JSON decoding method or function. Use local to constrain the scope of the change.

Tiny ^

JSON::Tiny compared with JSON::PP from the JSON distribution:


No configuration.


Perl 5.8.1 or newer. However, Perl 5.10 is the recommended minimum due to bugs in Perl 5.8's regular expression engine.


Incompatible with Exporter versions predating Perl 5.8.4. For older Perl versions upgrade Exporter to version 5.59 or newer.


David Oswald, <davido at cpan.org>

Code and tests were adapted from Mojo::JSON.


Direct support requests to the author. Direct bug reports to CPAN's Request Tracker (RT).

You can find documentation for this module with the perldoc command.

  perldoc JSON::Tiny

You may look for additional information at:


The Mojolicious team for their excellent product that offers a lightweight JSON implementation. This module was adapted from Mojo::JSON, chosen as a model because it is robust, minimal, and well tested. Mojo::JSON's tests were also adapted to a dependency-free design.

Christian Hansen, whos GitHub Gist provided the basis for Mojo::JSON, and subsequently JSON::Tiny.

Randal Schwartz showed his pure-regexp JSON parser (PerlMonks) to Los Angeles Perl Mongers (Sept 2012). He wasn't involved in JSON::Tiny, but my exploration of alternatives to his solution led to this fork of Mojo::JSON.


Copyright 2012-2014 David Oswald.

This program is free software, you can redistribute it and/or modify it under the terms of the Artistic License version 2.0.

See http://www.perlfoundation.org/artistic_license_2_0 for more information.


Mojo::JSON, JSON, RFC7159.

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