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JSON::Tiny - Minimalistic JSON. No dependencies.


  use JSON::Tiny qw(decode_json encode_json);

  my $bytes = encode_json {foo => [1, 2], bar => 'hello!', baz => \1};
  my $hash  = decode_json $bytes;


JSON::Tiny is a minimalistic standalone adaptation of Mojo::JSON, from the Mojolicious framework. It is a single-source-file module with under 300 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 among the fastest pure-Perl implementations 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 has a higher 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

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, and the character / to prevent XSS attacks.


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 $false = false;

False value, used because Perl has no equivalent.


  my $value = from_json $chars;

Decode JSON text that is not UTF-8 encoded to Perl value and die if decoding fails.


  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. An undef return value indicates a bare null. Dies if decoding fails.


  my $chars = to_json {i => '♥ Perl'};

Encode Perl value to JSON text without UTF-8 encoding it.


  my $true = true;

True value, used because Perl has no native equivalent.

More on Booleans

A reference to a scalar (even if blessed) is 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 overloaded stringification.

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. This must be set prior to calling a JSON decoding function. Use local to limit scope.


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

  • JSON::PP is configurable, but more complex. JSON::Tiny offers sane defaults, and no configuration.

  • Download and install with cpanm: JSON::PP, 5.2 seconds. JSON::Tiny, 1.9 seconds.

  • Minimal Dependencies: Both JSON::PP and JSON::Tiny only use core dependencies. JSON::Tiny requires Perl 5.8.4, while JSON::PP requires 5.6.

  • Simple Design: JSON has 2254 lines of code, six modules and five files. Distribution: 85KB.

    JSON::Tiny has under 300 lines of code; an embeddable single-file module. Distribution: 18KB.

  • JSON::PP has 42 functions and methods. JSON::Tiny has seven.

  • Performance:

                 Rate   JSON_PP JSON_Tiny
      JSON_PP   304/s        --      -52%
      JSON_Tiny 636/s      109%        --

    JSON uses JSON::XS if it's available, in which case JSON wins. See examples/ for benchmark code.

    JSON::Tiny's lightweight design reduces its startup time compared to the JSON module. This may benefit frequently run applications like CGI.

  • Light Memory Needs: Memory usage was tested with and Devel::MemoryTrace::Light by running examples/ and examples/

                 valgrind  Devel::MemoryTrace::Light
      JSON::PP   5.1MB     3.7MB
      JSON::Tiny 4.5MB     2.6MB


No configuration.


Perl 5.8.4 or newer. Perl 5.10+ is recommended due to bugs in Perl 5.8's regular expression engine.


Incompatible with Exporter versions older than 5.59 (ie, predating Perl 5.8.4).


David Oswald, <davido at>

Code and tests 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:


Mojolicious team for its lightweight JSON implementation. This module was adapted from Mojo::JSON 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 formed the basis for Mojo::JSON, and subsequently JSON::Tiny.

Randal Schwartz showed his pure-regexp JSON parser (PerlMonks) to Los Angeles Perl Mongers (09/2012). He wasn't involved in JSON::Tiny, but exploring alternatives to his solution led to this project.


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 for more information.


Mojo::JSON, JSON, RFC7159.