Jekyll is a static site generator written in Ruby: a program that takes plain text content and templates and produces a complete set of static HTML files, ready to be served by an ordinary web server without a database or application runtime. Its own documentation puts it plainly: “Jekyll is a static site generator. It takes text written in your favorite markup language and uses layouts to create a static website.” The project’s README adds that it is “a simple, blog-aware, static site generator perfect for personal, project, or organization sites.”
Tom Preston-Werner started Jekyll in 2008, and the tool’s fortunes became tied to GitHub, which he co-founded. GitHub adopted Jekyll as the engine behind GitHub Pages, the service that builds and hosts websites directly from a GitHub repository. The README states this connection directly: “Jekyll is the engine behind GitHub Pages, which you can use to host sites right from your GitHub repositories.” That coupling put Jekyll in front of a very large audience of developers and made it, for years, the default way programmers published documentation and blogs.
The “blog-aware” description points to Jekyll’s distinguishing feature. Beyond rendering individual pages, it understands the conventions of a blog: posts named by date, categories and tags, pagination, and the generation of feeds. Content is written in Markdown, page structure comes from Liquid templates, and per-file metadata is supplied through YAML front matter at the top of each file. The documentation describes the result as “a file-based CMS, without all the complexity,” taking content and rendering “Markdown and Liquid templates” into “a complete, static website.”
Architecturally, Jekyll established a pattern that later generators copied: a clear separation between content (Markdown plus front matter), presentation (layouts and includes), and configuration (a single site-wide file). Because the output is just static files, a Jekyll site is cheap to host, fast to serve, and resistant to the security problems that come with server-side content systems.
Jekyll is distributed as a Ruby gem and remains open source under the MIT License, maintained by a volunteer core team. It helped define the static-site-generator category and the broader Jamstack approach to building websites, and its conventions, Markdown content, front matter, and template layouts, shaped the generators, including Hugo, that followed it.