CodeSignal is described as 'The leading provider of assessments for technical hires. As the creator of the Predictive Coding Score, a measure of a candidates coding skills, CodeSignal provides HR teams with Certified Assessments, Custom Tests, and Live Interviews' and is a Code Learning service in the development category. There are more than 50 alternatives to CodeSignal, not only websites but also apps for a variety of platforms, including SaaS, Windows, Mac and Linux apps. The best CodeSignal alternative is HackerRank. It's not free, so if you're looking for a free alternative, you could try HackerRank or LeetCode. Other great sites and apps similar to CodeSignal are Codewars, Project Euler, CheckIO and CodinGame.
It have a big amount and varieties of tests