Exercism, freeCodeCamp, and LeetCode's free tier still anchor the category. New AI-assisted platforms have changed how you learn, not whether the basics matter.
Last updated: 2026-05-19
Coding practice sites differ wildly in what "free" means. Some (Exercism, freeCodeCamp) are fully free, no tier limits. Others (LeetCode, HackerRank) gate the best problems behind subscriptions. A third group (Codewars, Edabit) is fully free but monetized via ads or community premium. We ranked ten sites in 2026 based on what's actually accessible at zero cost, how good the practice problems are, and whether the platform helps you progress past beginner level. The list spans interview prep (LeetCode, AlgoExpert), language fluency (Exercism, Codewars), and project-based learning (freeCodeCamp, The Odin Project).
01
Exercism
Free forever (donation-supported)
Free, mentor-supported coding practice across 70+ programming languages.
Best for: Learning new languages with feedback from human mentors. exercism.org ↗
Human mentor feedback at no cost
Tracks for 70+ languages including niche ones (Elixir, Crystal, Rust)
Open-source platform and exercises
Less focused on interview-style algorithm problems
Mentor response time can vary
02
freeCodeCamp
Free forever (donation-supported nonprofit)
Full curriculum of web development, data science, and CS basics — entirely free.
Best for: Beginners wanting structured curriculum with hands-on projects. www.freecodecamp.org ↗
Comprehensive curriculum from beginner to advanced
Project-based certifications
Active forum and YouTube channel
Curriculum quality varies between tracks
Less suitable for algorithm-heavy interview prep
03
LeetCode
Free tier (~2500 problems), Premium $35/month
Industry-standard coding interview prep with a substantial free question set.
Best for: Software engineers preparing for technical interviews. leetcode.com ↗
Massive free problem set with solutions and discussions
Mock interviews and contest weekly
Best community for FAANG-style interview prep
Best problems and company-tagged sets are Premium-only
Some problems require Premium to unlock
04
Codewars
Free; Premium plans available
Gamified coding challenges (kata) ranked by difficulty.
Best for: Developers who want bite-sized daily problem-solving. www.codewars.com ↗
Gamified ranking system (8 kyu to 1 kyu)
Solutions visible after solving — great learning tool
55+ programming languages supported
Less rigorous than LeetCode for interview prep
Easier problems can feel repetitive
05
HackerRank
Free; some employer assessments paid
Coding challenges and skill certifications across multiple domains.
Best for: Engineers prepping for assessments used by hiring companies. www.hackerrank.com ↗
Skill certifications recognized by some employers
Strong SQL and database problem set
Tutorials for new languages
UI is busier than LeetCode
Less community-driven discussion
06
CodeSignal
Free practice arena; assessments via employer
Interview prep platform with company-specific assessments.
Best for: Engineers targeting companies that use CodeSignal for hiring. codesignal.com ↗
Adaptive difficulty in arcade mode
Mirror real interview tools used by FAANG
Solid free practice tier
Best mock assessments require company invite
Less community than LeetCode
07
The Odin Project
Free, open source
Open-source, free full-stack web development curriculum.
Best for: Self-taught developers building a real-world web dev portfolio. www.theodinproject.com ↗
Project-heavy, real-world curriculum
Open-source — community contributions keep it current
Discord community and learning paths
Web dev focused; not for data science or systems work
Some external resources have moved or paywalled
08
Project Euler
Free
Math-heavy programming problems that reward elegant solutions.
Best for: Developers who like math and want to write efficient algorithms. projecteuler.net ↗
Math-meets-programming problems unique to the site
Problems get harder gradually
Free since 2001 with no monetization
Solutions are by design hidden — less collaborative
Best for: Beginners ramping up basic problem-solving fluency. edabit.com ↗
Very approachable for early learners
Wide language coverage
Quick wins keep motivation up
Easy problems plateau fast
Free tier shows ads
10
AlgoExpert
Paid only ($99/year)
Curated interview prep platform — not free, included for context.
Best for: Engineers who want video-explained algorithm walk-throughs. www.algoexpert.io ↗
High-quality video explanations
Curated 200+ interview questions
Mock interview practice
No free tier — paid only
Less breadth than LeetCode
Frequently asked
Should I do LeetCode or Codewars first?
For interview prep at large tech companies, LeetCode. For language fluency and gentle daily practice, Codewars. Many engineers use both: Codewars to stay warm, LeetCode when actively interviewing.
Is the free LeetCode tier enough for FAANG interviews?
For most candidates, yes. The free tier includes the bulk of important questions. Premium adds company-tagged questions, mock assessments, and video solutions — useful but not strictly required if you're disciplined.
What's the catch with Exercism being free?
Exercism runs on donations and volunteer mentors. The platform is open source and the founder has been transparent about funding. Mentor response times can stretch when volunteer capacity is low, but the core experience is genuinely free.
Can AI assistants like Copilot or ChatGPT replace coding practice sites?
No. AI tools help you write code, but practice sites build problem-solving fluency and pattern recognition under constraints — which is what interviews actually test. Use AI tools after solving, not instead of solving.
What's the best free site for SQL practice?
HackerRank's SQL track and LeetCode's database problems are both strong free tiers. SQLZoo is a free standalone site focused entirely on SQL with interactive exercises.