Snapshot testing captures the output of functions or API responses and compares them to stored snapshots to detect unexpected changes. With over 12 years of Node.js development experience since 2014 and as the creator of CoreUI, I’ve used snapshot tests to catch regressions in APIs. Jest provides built-in snapshot testing that creates readable, version-controlled snapshots of complex data structures and responses. This approach catches unexpected changes in data formats, API responses, and object structures without manual assertions.