Nokogiri (鋸) makes it easy and painless to work with XML and HTML from Ruby. It provides a sensible, easy-to-understand API for reading, writing, modifying, and querying documents. It is fast and standards-compliant by relying on native parsers like libxml2, libgumbo, or xerces.

A fast XML parser and object serializer that uses only standard C lib. Optimized XML (Ox), as the name implies was written to provide speed optimized XML handling. It was designed to be an alternative to Nokogiri and other Ruby XML parsers for generic XML parsing and as an alternative to Marshal for Object serialization.

Oga is an XML/HTML parser written in Ruby.

The Libxml-Ruby project provides Ruby language bindings for the GNOME Libxml2 XML toolkit. It is free software, released under the MIT License. Libxml-ruby's primary advantage over REXML is performance - if speed is your need, these are good libraries to consider, as demonstrated by the informal benchmark below.

a swift, liberal HTML parser with a fantastic library

Extract useful data from HTML and XML with ease!

Rubyful Soup is a *ML parser that makes screen-scraping easy. It won't choke on bad markup, and it's easy to locate the part of a document you want.

scRUBYt! is an easy to learn and use, yet powerful and effective web scraping framework. It's most interesting part is a Web-scraping DSL built on HPricot and WWW::Mechanize, which allows to navigate to the page of interest, then extract and query data records with a few lines of code. It is hard to describe scRUBYt! in a few sentences - you have to see it for yourself!

A new short XML Parsing Algorithm implemented directly in less-than-500 lines. An easy-to-use XML Parser without any Native Dependencies. Its under continuous improvement as being used/tested under my other xml-parsing required projects. [What, Why, HowTo]: http://justfewtuts.blogspot.in/2012/03/xml-motor-what-it-is-how-why-should-you.html