Exercism

Cursa

cursa.app

Mimo

mimo.org

freeCodeCamp

freecodecamp.org

Programiz

programiz.pro

Brilliant

brilliant.org

Programming Hub

programminghub.io

CodeChef

codechef.com

Educative

educative.io

Codewars

codewars.com

Programming Hero

web.programming-hero.com

Codeforces

codeforces.com

Learn Code The Hard Way

learncodethehardway.org

codedamn

codedamn.com

Edabit

edabit.com

Studytonight

studytonight.com

Reflex

reflexmath.com

Codementor

codementor.io

CodeCombat

codecombat.com

Expii

expii.com

CodeGym

codegym.cc

Proge

progegame.com

Practicum

practicum.com

LabEx

labex.io

BigDevSoon

bigdevsoon.me