Hacker News on 19 January 2015

• Matter.js – A 2D rigid body physics engine for the web
• The Best Entrepreneur I Know
• The Whole Haystack: The N.S.A. claims it needs access to all our phone records
• N.S.A. Tapped into North Korean Networks Before Sony Attack, Officials Say
• Python Tips and Traps
• Node.js and io.js – Very different in performance
• Path Tracing 3D Fractals
• Ask HN: What's the best way to write an API spec?
• Auto Recovery for Amazon EC2
• Chiptune