Keyframes gives you a visual timeline to help you create, view, and run animations without having to go back and forth between your browser and editor.

Architecture Guidance
Common application patterns with .NET
Practical advice, best practices, and sample applications to help you implement different application patterns using .NET

Swift, Apple's powerful new programming language, is now open source on GitHub. Developers can submit bug fixes and enhancements, and help bring the language to new platforms. 

If you are working with .NET, then there are some very easy to consume libraries to help you host a WebSocket server or connect as a WebSocket client. 

Firefox Developer Edition 44, released last week, includes a brand new memory tool to help you understand how your web applications are using and retaining memory.