Creating complete RESTful API according requirements. Making business logic more flexible, reliable and powerful. Providing security for each API endpoint. Excellent documentatiting of API using Swagger or Postman for best description of each method using by Mobile or Frontend or anothers Backend developers. Working with Real-time data. Deploying on different hostings using Nginx or Docker. Using PostgreSQL as main database and MongoDB as NOSQL. Generally writting code on Python3.5+ with Django rest framemork or Flask. Also servers could be written on GOlang using GIN framework, Ruby on Rails, PHP Laravel. Generall knowledge about HTML, CSS, Javascript(pure) and JS frameworks(React, Angular, Vue) for Frontend development.