A software engineer is a professional who designs, develops, maintains, tests and evaluates computer software. They are responsible for creating software that meets user requirements and solves specific problems. Software engineers use programming languages such as Java, C++, Python and HTML to create applications that run on computers or mobile devices. They also work with databases to store data and create reports. Software engineers may also be involved in the design of user interfaces for applications. In addition, they may be responsible for testing the software to ensure it meets quality standards before it is released to the public.