Fat-Free Framework

A powerful yet easy-to-use PHP micro-framework designed to help you build dynamic and robust web applications - fast!

  • full-featured toolkit
  • super lightweight code base with just ~90kb
  • easy to learn, use and extend

Create Powerful Apps

Take advantage of the built-in features. Develop apps that really rock. F3 gives you solid foundation, a mature code base, and a no-nonsense approach to writing Web applications.

Blazing Fast Kickstart

Whether you're a novice or an expert PHP programmer, F3 will get you up and running in no time. No unnecessary and painstaking installation procedures. No complex configuration required. No convoluted directory structures.

Write Less Code

Speed up your development process. F3 is lightweight, easy-to-use, and fast. Most of all, it doesn't get in your way. It has a gentle learning curve so you save money on training expenses.

Rocket Science Included

Under the hood is an easy-to-use Web development tool kit, a high-performance URL routing, multi-protocol cache engine, built-in code highlighting, and support for multilingual i18n applications.

Start Now

There's no better time to start developing Web applications the easy way than right now!

composer require bcosca/fatfree-core
Direct Download


You can also grab the unit test package or fetch the nightly build if you live in the fast lane. See the version changelog and system requirements for additional information. There is also composer support.


Join us on GitHub to make F3 even better.


Do you need some help for getting started? Or just want to share some thoughts? Meet other users at the F3 Google Group and Slack or Matrix.

F3 supports both SQL and NoSQL databases off-the-shelf: MySQL, SQLite, MSSQL/Sybase, PostgreSQL, MongoDB and its own lightning fast Flat-File DB (we call it Jig). It also comes with powerful object-relational mappers for data abstraction and modeling that are just as lightweight as the framework. No configuration needed.

F3 can also shield you from spam and DoS attacks, by performing DNSBL checks. It can increase your server health and uptime, by controlling web server traffic with profile analysis and bandwidth throttle.

That's not all. F3 is packaged with other optional plug-ins that extend its capabilities:

  • Fast and clean template engine
  • Unit testing toolkit
  • Database-managed sessions
  • Markdown-to-HTML converter
  • Atom/RSS feed reader
  • Image processor
  • Geodata handler
  • On-the-fly Javascript/CSS compressor
  • OpenID (consumer)
  • Custom logger
  • Basket/Shopping cart
  • Pingback server/consumer
  • Unicode-aware string functions
  • SMTP over SSL/TLS
  • Tools for communicating with other servers
  • Data Validation
  • and more Plugins from the F3-Community

Unlike other frameworks, F3 aims to be usable - not usual.

The philosophy behind the framework and its approach to software architecture is towards minimalism in structural components, avoiding application complexity and striking a balance between code elegance, application performance and programmer productivity.

Here is a short video that will give you a brief introduction to the framework.