A person who developers an application & binds it with technologies (i.e. a server and a database) together to work is what we define as Backend Developer. Therefore, a backend developer is responsible for the programming of the website or an application in its dynamic components. The programming of the different components of the website (i.e. pages, forms, functions, databases) and structuring of documents is to be framed to different standards.
A professional backend developer should have knowledge of the following tools technologies and tools:
Of course with the knowledge of one of them and be expert in that, characterizes it as a backend developer. Of course, showing great interest in learning about any developments in the web environment like Capistrano, GIT, vagrant, node.js does too.
One of the best ways to note the skills you possess and demonstrate that you are really a backend programmer, is to keep track of your projects & skills utilized. Certainly when hiring backend developers, web development companies weighs your skills and they will help you to lean on your profile. Another important factor in hiring a freelance programmer, is to have a date with the best covers work performed, testimonials or recommendations from your customers about satisfaction, your support for the development of their project portfolio. Even more important, if you work as a freelance backend programmer, you should think about having a repository of your personal projects. Having a github repository is most recommended, and definitely this will be a plus when hiring a backend developer.
When faced with a proposal of hiring, seeks interior on the subject and be quite honest about your skills and knowledge as this will give more confidence to your customers and influence their decision to hire you as a freelancer and project developer.