Circuito.io - Instant code and wiring for your project
Arduino IDE - Arduino is an open-source electronics prototyping platform based on flexible, easy-to-use hardware...
library.io - Learn electronics and easily create circuit boards online
B4R - Development tool for native Arduino programs.
PlatformIO - Next-generation IDE for IoT
Atmel Studio - Atmel Studio is the integrated development platform (IDP) for developing and debugging Atmel.