LeetCode has become synonymous with coding interview preparation. Founded in 2015, the platform hosts a massive collection of over 3,000 algorithmic and data structure problems — the same types of questions asked in technical interviews at companies like Google, Amazon, Meta, and Microsoft. If you’re preparing for a software engineering interview, chances are you’ve heard someone say “just grind LeetCode.”
Problems are categorized by difficulty (easy, medium, hard) and tagged by topic — arrays, trees, dynamic programming, graphs, and dozens more. Each problem includes a description, test cases, and a built-in code editor supporting multiple languages. After submitting a solution, LeetCode runs it against hidden test cases and provides metrics on runtime and memory usage.
The platform operates on a freemium model. Free users get access to most problems, while Premium subscribers unlock company-specific question lists, sorting by frequency, and additional features. The company-tagged questions are particularly valuable — they show which problems specific companies have actually asked in interviews.
LeetCode also runs weekly and biweekly coding contests that attract thousands of competitive programmers. The discussion forums are active, with users sharing detailed solution explanations and multiple approaches for each problem. The platform has built a huge community — millions of developers use it regularly, and “LeetCode-style” has become a standard shorthand for algorithmic interview questions in the tech industry.
