An open-source Delphi-compatible RAD IDE for Free Pascal, risen from the failed Megido project in 1999. Provides the Lazarus Component Library (LCL) as a cross-platform alternative to Delphi's VCL.
Lazarus Component Library (LCL) provides cross-platform widget abstraction supporting GTK2/3, Qt4/5, Win32/64, Cocoa, and Carbon backends. Form-based visual designer with property inspector. Built-in debugger integration. Supports cross-compilation via Free Pascal's multi-target capabilities.
The first attempt to create a visual IDE for Free Pascal was the Megido project, which started in 1998 but quickly dissolved. In February 1999, Cliff Baeseman, Shane Miller, and Michael A. Hess founded Lazarus from Megido's ashes, aiming to create a free, cross-platform RAD (Rapid Application Development) environment compatible with Delphi's visual development paradigm.
Lazarus's primary goal was to provide a Delphi-like experience on Linux, where developers faced a severe shortage of GUI development tools for Object Pascal. The project developed the Lazarus Component Library (LCL), designed to be as compatible as possible with Delphi's Visual Component Library (VCL) while supporting multiple widget toolkits (GTK, Qt, Win32, Cocoa, and more) for true cross-platform development.
Like Free Pascal itself, Lazarus is not a code fork of Delphi — it is an independent reimplementation of Delphi's concepts. However, it represents the open-source community's most significant response to Delphi's proprietary pricing and platform limitations. Lazarus enables developers to create GUI applications that compile natively on Windows, Linux, macOS, FreeBSD, and other platforms from a single codebase. Its form designer, component palette, and object inspector closely mirror Delphi's workflow.
Lazarus has become the most popular IDE for Free Pascal programmers and is used by numerous notable projects including Cheat Engine, PeaZip, Beyond Compare (Linux/Mac), and Cartes du Ciel. The project reached version 4.0 in 2025, marking over 25 years of continuous development.
Megido project starts as first attempt at Free Pascal IDE
Megido dissolves; Lazarus founded by Baeseman, Miller, and Hess
Lazarus 1.0 released after 13 years of development
Lazarus 4.0 released
Became the primary open-source alternative to Delphi for visual Pascal development. Enabled cross-platform GUI development with Object Pascal. Kept the Delphi development paradigm accessible to developers unwilling or unable to pay for commercial Delphi licenses.