In this article, we present Worldsens, a fast and accurate development framework for sensor network applications. World-sens offers an integrated platform for the design, development, performance evaluation and profiling of applications. It relies on two simulators, WSNet and WSim, which are used throughout the application design and implementation, from the high level design choices to the implementation validation. WSNet is a modular event-driven wireless network simulator while WSim is a full platform hardware simulator which takes the target binary code as input and uses instruction cycles as time reference. WSNet and WSim can be used in conjunction to offer a distributed simulation of sensor networks with instruction and radio byte accuracy.