A Revolution for developing of safety critical application Developing safety critical applications often requires rare human resources to complete successfully while off-the-shelf block solutions appear difficult to adapt especially during short-term projects. Developed during the R&D project FUI LCHIP[5], the CLEARSY Safety Platform fulfills a need for a technical solution to overcome the difficulties to develop SIL3/SIL4 system. Its technology is based on a smart combination of diverse hardware (2x PIC 32 micro-controllers) and a formal method with proof heavily used in the railways industry for decades. It avoids most testing and ensures safety at the highest level. The CLEARSY Safety Platform is both a software and a hardware platform aimed at designing and executing safety critical applications. One formal modelling language (B) is used to program the board. Programs are developed using a dedicated IDE or could be the by-product of some translation from a Domain Specific Language to B. The IDE takes care of the verification of the software (type check, proof, compilation) and then ensures its uploading to the hardware platform. Program is guaranteed to execute until a misbehaviour is detected, leading to a safe restricted mode where board outputs are deactivated. Added value The CLEARSY Safety Platform eases the development of safety critical applications as:-it covers the whole development cycle of control-command systems based on digital inputs/outputs.-development time is shortened as the safety principles are built-in, and are out of reach of the developer who cannot alter them. Development is focused on the behaviour.