A coding challenge is a task or competition designed to test a programmer's skills in writing code. Participants are often given a specific problem to solve within a set time frame, using programming languages like Python, Java, or C++. These challenges can vary in difficulty and may focus on algorithms, data structures, or other technical concepts. Many coding challenges are hosted on online platforms, such as LeetCode or HackerRank, where users can submit their solutions and receive instant feedback. They are popular among developers looking to improve their coding abilities, prepare for job interviews, or compete against others in a fun and engaging way.