The .NET Compiler Platform ("Roslyn") provides open-source C# and Visual Basic compilers with rich code analysis APIs.

Research platform for new language concepts and compiler technologies for Scala.

MonoDevelop is a cross platform IDE mostly aimed at Mono/.NET developers

https://github.com/solid/node-solid-server

Mantl is a modern platform for rapidly deploying globally distributed services

Our official community can be found at https://slack.ghost.org

Ansible is a radically simple IT automation platform that makes your applications and systems easier to deploy. Avoid writing scripts or custom code to deploy and update your applications— automate in a language that approaches plain English, using SSH, with no agents to install on remote systems.

Open source Platform as a Service (PaaS).

Main repository for the Cadasta platform, an online system for recording and managing land tenure information.

Welcome to the SecureDrop chatroom. Code of Conduct: https://github.com/freedomofpress/securedrop/blob/develop/CODE_OF_CONDUCT.md

A platform to create, publish and edit sites

Next generation programming language, currently in development

An experimental Go cross platform UI library.

Cross platform parser for the Gherkin language. Used by Cucumber to parse .feature files.

An implementation of StyleCop rules using the .NET Compiler Platform

Famo.us is a JavaScript platform for everyone who wants to build beautiful experiences on any device

Cross platform GUI framework for desktop and mobile applications in .NET

A C++ / Python platform to perform parallel computations of optimisation tasks (global and local) via the asynchronous generalized island model. State of the art optimization algorithms are included. A common interface is provided to other optimization frameworks/algorithms such as NLOPT, SciPy, SNOPT, IPOPT, GSL

Cross platform xamarin and windows plugins for PCLs

Orchestra Platform Application Skeleton

A platform for developing apps using JRuby on Android.

Benchmarking platform and competition for source extraction from imaging data

Machine-to-machine instant messaging platform for the internet of things #IoT

An application development platform

TinyMCE is a platform independent web based Javascript HTML WYSIWYG editor control released as Open Source under LGPL.

A cross platform manga/doujinshi manager with tagging support

MODx Revolution - Content Application Platform

A .NET GIS solution that is fast and reliable for the .NET platform.

Cross Platform UI Kit powered by Blink/Chromium Content Lib

An Enterprise-grade API Management Platform for Teams. RESTFiddle helps you design, develop, test and release APIs.

Home of the StackStorm automation platform.

An API-first, open source software platform for the Internet of Things.

Cross Platform GUI for D programming language

Probably the coolest anime discovery platform around.

The DataTank is open source data platform, which you can use to transform any dataset into an HTTP API.

DIT4C - This is the **public** room, which is searchable by Google et al. If you have private info you want to post put it in the "dit4c" org room.

Next generation desktop application development platform for the JVM

Open-sourced hangouts platform for ethereum.builders (learning-to-code platform). Based on CodeBuddies.org hangouts platform. Built on top of Telescope, another open-sourced project.

An open-source, in-house service platform with a PaaS-like workflow, built on Docker, CoreOS, Etcd and Fleet. This repository houses the documentation and installation scripts.

Cloud Operations Platform

Hybrid Meteor application platform. Build once, look good everywhere!

Test Suites for Web Platform specifications · IRC: http://irc.w3.org/?channels=testing

cloud-scale consistency platform

The Metamaps Knowledge Cartography platform, in private beta at:

Welcome to this room if you want a chat about the work of the Ripple Foundation. http://ripple.foundation

Cross platform browser plugin for serial port communication from JavaScript

JS Belgrade website (Ghost platform)

Open Source Carpooling Platform

a data management platform

CANBus Triple – The car hacking platform