Codacy - Automatically reviews code style, security, duplication, complexity, and coverage on every change while tracking code quality throughout your sprints.

HackerRank - HackerRank is a platform that allows companies to conduct interviews remotely to hire developers and for technical assessment purposes.

SonarQube - SonarQube, a core component of the Sonar solution, is an open source, self-managed tool that systematically helps developers and organizations deliver Clean Code.

HackerEarth - HackerEarth is the network of top developers across the world. They connect to start-ups, tech companies, organizations and discover the best developer jobs. They participate in programming challenges and compete against other top developers.

CodeClimate - Code Climate provides automated code review for your apps, letting you fix quality and security issues before they hit production. We check every commit, branch and pull request for changes in quality and potential vulnerabilities.

Coding View - Coding View is live collaborative coding environmentdesigned for technical phone interviews. It features web version of Visual Studio Code, as well as access to real terminal. It has a built-in compiler for most popular programming languages.