Dillo is a minimalistic web browser particularly intended for older or slower computers and embedded systems. It supports only plain HTML/XHTML (with CSS rendering) and images over HTTP; scripting is ignored entirely. Current versions of Dillo can run on Linux, BSD, OS X, IRIX and Cygwin. Due to its small size, it is the browser of choice in several space-conscious Linux distributions. Released under the GNU GPL-3.0-or-later, Dillo is free software.
Chilean software engineer Jorge Arellano Cid conceived the Dillo project in late 1999, publishing the first version of Dillo in December of that year. His primary goal in creating Dillo was to democratize access to information. Arellano Cid believed that no one should have to buy a new computer or pay for broadband in order to enjoy the World Wide Web. To this end, he designed Dillo to be small, fast, and efficient, capable of performing well even on an Intel 80486 CPU with a dial-up Internet access.
Dillo was originally written in the C programming language with the GTK+ GUI toolkit. The first versions were based on an earlier browser called Armadillo, hence the name. Dillo 2, written with both C and C++ components and the Fast Light Toolkit (FLTK), was released on October 14, 2008. Text antialiasing, support for character sets other than Latin-1, HTTP compression capability, and improved page rendering were all added. The move to FLTK from GTK+ also removed many of the project's dependencies and reduced Dillo's memory footprint by 50%.
In 2011, Dillo-3.x was released, using FLTK-1.3. According to the Changelog, this change was prompted in part by the lack of an official release of FLTK-2, which stopped Dillo-2's inclusion in lightweight distributions for which it would otherwise have been suitable.
Jorge Arellano Cid is still Dillo's lead developer today. Dillo is funded by private donations; efforts to obtain public grants and corporate sponsors have been unsuccessful. Lack of funding led to a slowdown in development in 2006, and a complete stop in 2007.