A long, maintained list of services with genuine free tiers for developers: hosting, databases, CI, email, monitoring and more.
A gigantic curated list of free APIs, sorted by category, with auth and CORS support noted for each one.
Every fibre-optic cable on the ocean floor, drawn on one map with its landing points, owners and dates. The physical internet, suddenly legible.
Thousands of community-made cheat sheets for programming languages, tools and shortcuts, all printable.
Like Can I use, but for email clients. Look up any HTML or CSS feature and see whether Gmail, Outlook and Apple Mail will actually render it.
