Proficient knowledge of Ruby and Ruby on Rails framework; Good knowledge about backend, api development; Basic knowledge of server-side mechanisms in general; Good knowledge of Crystal and Amber framework; Basic knowledge of JS and js libraries; Experience in designing and developing web-based applications; Good knowledge of browser APIs (Chrome, Firefox, Safari, IE, Edge); Experienced in automated development processes; Good Git knowledge; Experienced in writing unit, integration and e.t.c. tests; Good knowledge of unix systems; Good communication skills.