Ruby Standard Gems

About the Gemified Standard Library

Ruby's standard library is in the process of being gemified. More and more libraries will be turned into RubyGems, which can be updated independently from Ruby.

There are two different kinds of standard gems:

Checkout Hiroshi Shibata's talk at RubyConf 2017 for more info. Also see Ruby issue #5481 for the current state of the gemification project.

Standard Gems Version Data

Every Ruby version ships a specific set of default and bundled gems. The tables below list included gems of the current Ruby version 2.5.3. There is also version comparison that shows which Ruby version comes with which gem versions. The raw data is available as default_gems.json and bundled_gems.json.

Default Gems (Ruby 2.5.3)

Gem Version Description Resources
bigdecimal c 1.3.4 Support for arbitrary-precision floating point decimal arithmetic RubyGems, GitHub, MRI, RDoc
cmath 1.0.0 Trigonometric and transcendental functions for complex numbers RubyGems, GitHub, MRI, RDoc
csv 1.0.0 Support for CSV (Comma-separated Values) RubyGems, GitHub, MRI (1), MRI (2), RDoc
date c 1.0.0 The Date and DateTime classes RubyGems, GitHub, MRI, RDoc (1), RDoc (2)
dbm c 1.0.0 Support for DBM databases RubyGems, GitHub, MRI, RDoc
etc c 1.0.0 Access UNIX info from /etc RubyGems, GitHub, MRI, RDoc
fcntl c 1.0.0 Loads values from the OS' fcntl.h to be used for low-level file descriptor manipulation system calls with IO#fcntl and IO.sysopen RubyGems, GitHub, MRI, RDoc
fiddle c 1.0.0 Support for FFI (Foreign Function Interface) RubyGems, GitHub, MRI, RDoc
fileutils 1.0.2 Utilities for working with the file system, such as copying, moving, or deleting files RubyGems, GitHub, MRI, RDoc
gdbm c 2.0.0 Support for GDBM databases RubyGems, GitHub, MRI, RDoc
io-console c 0.4.6 Patches IO for simple and portable access to the console RubyGems, GitHub, MRI, RDoc
ipaddr 1.2.0 IP address manipulation (IPv4 and IPv6) RubyGems, GitHub, MRI, RDoc
json c 2.1.0 Support for JSON (JavaScript Object Notation) RubyGems, GitHub, MRI, RDoc
openssl c 2.1.2 Wraps OpenSSL for cryptographic functionality RubyGems, GitHub, MRI, RDoc
psych c 3.0.2 Support for YAML (YAML Ain't Markup Language) RubyGems, GitHub, MRI, RDoc
rdoc 6.0.1 Ruby documentation generator RubyGems, GitHub, MRI (1), MRI (2), RDoc
rubygems 2.7.6 RubyGems allows you to download, install, and use Ruby software packages on your system RubyGems, GitHub, MRI (1), MRI (2), RDoc
scanf 1.0.0 Pure-Ruby scanf implementation RubyGems, GitHub, MRI, RDoc
sdbm c 1.0.0 Support for SDBM databases RubyGems, GitHub, MRI, RDoc
stringio c 0.0.1 Makes strings behave like IO objects GitHub, MRI, RDoc
strscan c 1.0.0 Lexical string scanning GitHub, MRI, RDoc
webrick 1.4.2 HTTP Server RubyGems, GitHub, MRI (1), MRI (2), RDoc
zlib c 1.0.0 Interface to the zlib compression library RubyGems, GitHub, MRI, RDoc

Bundled Gems (Ruby 2.5.3)

Gem Version Description Resources
did_you_mean 1.2.0 Patches error messages to suggest correct spelling of methods/classes/variables RubyGems, GitHub
minitest 5.10.3 Test/spec framework, comes with mocking and benchmark capabilities RubyGems, GitHub
net-telnet 0.1.1 Support for Telnet RubyGems, GitHub
power_assert 1.1.1 Debug tool that displays intermediate results of a method chain RubyGems, GitHub
rake 12.3.0 A Ruby task runner, inspired by make RubyGems, GitHub
test-unit 3.2.7 A xUnit family unit testing framework (compatibility layer for minitest) RubyGems, GitHub
xmlrpc 0.3.0 Remote Procedure Calls via XML and HTTP RubyGems, GitHub

Gems per Ruby Version

Gemification Progress

New standard gems in Ruby: 2.6 - 2.5 - 2.4 - 2.3 - 2.2

Non-Gemified Standard Libraries

A list of standard libraries which have not yet turned into gems can be found at libraries. The respective JSON file is at libraries.json.


This page and the JSON data files it is based on are maintained on GitHub. Originally based on episode 20 of Idiosyncratic Ruby and put together by Jan Lelis.

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