As a junior, intermediate and sometimes (unfortunately) even senior software developer, you might face a coding challenge as one of the steps in your interview process with a new potential employer.
The programming challenges can take a few forms, an algorithmic / logic challenge on an established platform, an in-house test, an algorithmic / logic whiteboard test or implementing a dev server ready solution from or almost from scratch.
For a junior developer, it is paramount to have at least some training and practice when it comes to common algorithm and logic problems. We have compiled a list of what is, in our opinion, the best coding challenge websites. It is suggested to grind through at least a couple of problems per day if you’re currently on the job market for a new opportunity. This can also be used for intermediate and even senior developers in order not to get too rusty. It’s programming after all, can’t be that bad!
Related: How to interview as a software developer
1. Codewars
Difficulty: Beginner – Intermediate
- 20+ programming languages to choose from
- You can review other’s solutions once you’ve solved a challenge
- You can write your own unit test cases
- You can earn points and climb up the rankings by solving coding challenges
2. HackerRank
Difficulty: Intermediate – Advanced
- 20+ programming languages to choose from
- Integrated job board for your convenience (might be interesting)
- More computer science focused – Algorithms, Mathematics, SQL, Functional Programming, AI, etc.
- You can review other’s solutions and there’s a leader board once you’ve solved a challenge
- Offers pair coding mode
3. LeetCode
Difficulty: Intermediate – Advanced
- Best algorithm challenges
- You must have an understanding of data structures (binary trees, linked lists, heaps, etc.)
- Has a Mock Interview section for job interview preparation
- Has coding contests
4. Codingame
Difficulty: Beginner – Intermediate
- Quite a few programming languages available
- Multiple types of challenges that all seem to be pretty fun
- With this website, you don’t solve coding challenges but rather write code to play a game
- The games you’ll write with Codingame are quite nice to play, they essentially provide all the graphics and it’s up to you to write the game logic behind. Here’s an example
- Codingame is gaining popularity for technical interviews with quite a few companies in Canada
5. Edabit
Difficulty: Beginner – Intermediate
- 10+ programming languages to choose from
- Multiple types of challenges but predominantly algorithms – very good to teach you to think like a programmer
- Some say it’s the Duolingo of learning how to code 🙂
As a bonus, here’s a little snippet from the founder of Edabit:
