Xapian is a highly adaptable toolkit which allows developers to easily add advanced indexing and search facilities to their own applications. It supports the Probabilistic Information Retrieval model and also supports a rich set of boolean query operators.

Test regular expressions directly in the browser with many different programming languages.

A tool to easily build vagrant base boxes or kvm, virtualbox and fusion images.

Travis CI is a distributed continuous integration for the open source community. It is integrated with GitHub and offers first class support for multiple technologies.

Selbstständige der Leipziger Kultur- und Kreativwirtschaft haben mit Unterstützung der Initiative “Leipziger Agenda 21” eine Schnittstelle (API) für den Zugriff auf Leipziger Daten entwickelt. Über diese Schnittstelle können strukturierte öffentliche Daten der Stadt Leipzig zur freien Verwendung abgerufen werden. Externe Entwickler können nun Anwendungen entwickeln, die die diese Daten verwenden.

Vagrant is a tool for building and distributing virtualized development environments. By providing automated creation and provisioning of virtual machines using Oracle’s VirtualBox, Vagrant provides the tools to create and configure lightweight, reproducible, and portable virtual environments.

ScraperWiki is all the tools you need for Screen Scraping, Data Mining & visualisation.

Homebrew is the easiest and most flexible way to install the UNIX tools Apple didn't include with OS X.

Should assertions in Python as clear and readable as possible.

Chef’s documentation is vast and broken up into many pages on the Opscode wiki. The goal here is to index this information and give a brief explanation of each topic without going into too much depth.

ChiliProject is a web based project management system. It supports your team throughout the complete project life cycle, from setting up and discussing a project plan, over tracking issues and reporting work progress to collaboratively sharing knowledge.

Tenjin is a full-featured template engine available in several script languages.

The Embedly API allows developers to embed videos, images and rich media from more than hundred services through one API.

Graylog2 is an open source syslog implementation that stores your logs in MongoDB. It consists of a server written in Java that accepts your syslog messages via TCP or UDP and stores it in the database. The second part is a Ruby on Rails web interface that allows you to view the log messages.

Rhodes is an open source framework to rapidly build NATIVE apps for all major smartphone operating systems (iPhone, Windows Mobile, RIM, Symbian and Android). These are true native device applications (NOT mobile web apps) which work with synchronized local data and take advantage of device capabilities such as GPS, PIM contacts and camera.

Logic-less templates available in Ruby, JavaScript, Python, Erlang, Go, Lua, and for node.js.

MapFish is composed of two parts: MapFish Client and MapFish Server. MapFish Client is a JavaScript framework based on OpenLayers for the mapping part, on ExtJS and GeoExt for the GUI part. MapFish Server is responsible for server side treatments and is composed of several modules which can be implemented in several languages such as Python, Java, Ruby, PHP or others.

The philosophy of RuPy is to put together Python & Ruby experts with young programmers and to support a good communication channel for East-West exchange of prospective ideas.

Redmine is a flexible project management web application. Written using Ruby on Rails framework, it is cross-platform and cross-database.