library.io - Learn electronics and easily create circuit boards online
Arduino IDE - Arduino is an open-source electronics prototyping platform based on flexible, easy-to-use hardware...
Circuito.io - Instant code and wiring for your project
PlatformIO - Next-generation IDE for IoT
Circuit Stickers - Peel-and-stick electronics for crafting circuits.
MINIBLOQ - miniBloq is an open source graphical programming environment for Multiplo™, Arduino™, physical computing devices and robots.