What is the difference between smoke testing and sanity testing?

Smoke testing is a quick pass on a new build to see if core features work enough to continue deeper testing - think “does the app start and can I log in?” Sanity testing is narrower: it verifies that a specific change or fix works and did not break related areas. Smoke runs are often the same checklist every build; sanity checks vary per ticket or bug fix. Both are shallow compared to full regression, but smoke gates the pipeline while sanity validates a focused hypothesis. Neither replaces structured regression or exploratory work. Teams that confuse the two often run the wrong checks at the wrong time.