AcornDB is a high performance, small footprint, transactional object oriented database written entirely in Java. It stores data in the application's native format, so no runtime data translation is required. AcornDB supports full ACID transactions and recovery. It provides an easy-to-use interface like query-by-example, object query API, automatic class schema recognition allowing programmers to store and retrieve information quickly, simply and reliably.

Adminer (formerly phpMinAdmin) is a full-featured MySQL management tool written in PHP. Conversely to phpMyAdmin, it consist of a single file ready to deploy to the target server.

Æjaks combines the server-side Ajax windowing system Echo2 with the powerful simplicity of the Tcl langauge. The result is a rich development environment in which to develop Ajax-based web applications, often with much less code to write. Æjaks runs on top of a Java Servlet engine, and can make use of any existing Java library.

Aero is a PHP5 framework with a highly modular design, intended for programmers who prefer to control every aspect of the application they build. Unlike many other frameworks Aero does not make any decisions for you, there are very few conventions or rules you should follow.

Agavi is a powerful, scalable PHP5 application framework that follows the MVC paradigm. It enables developers to write clean, maintainable and extensible code. Agavi puts choice and freedom over limiting conventions, and focuses on sustained quality rather than short-sighted decisions.

Agile Project Management Tool (APMT) is the automation of Scrum which is an Agile methodology. APMT is a Highly Customizable and Comprehensive Tool. It covers all aspects of Scrum methodology like Maintaining the Project Backlog, Creating Sprints, Creating Sprint Backlog, Conducting Daily ScrumMeeting and Burndown Chart.

Agile Tracking Tool can be used as an open source tool for Agile software development. Features:
- Maintaining multiple projects
- Maintaining your backlog
- Tracking how work develops over time
- Support for iterations
- Forecast when work will be done using the measured velocity
- Export and import all your valuable data (xml format).

Agile-Trac adds the concept of Iterations to Trac which allows a more useful Roadmap view with predicted completion date ranges and relatively sized progress indicators. User stories (and tickets in general) can have one or more completion stages defined for them. These are relatively sized using a sizing scale that you define.

Agilefant is a simple but powerful solution for managing software development projects and related activities. It brings together the perspectives of organizing daily work, long-term product and release planning and project portfolio management.

AgileUnit is a small framework developed to increase the feedback loop while developing applications. Get feedbacks from your app while your customer is using it. Figure out what your customer really want early, which functions are most used and which not. Merge synergy of requirement, development, testing and maintenance to one piece.