Monoliths are all-in-one apps, while microservices are a team of specialized features.In a monolith, if one part breaks, the whole app is affected; in microservices, if one piece crashes, the others keep functioning.Microservices offer flexibility and resilience, while monoliths are simpler and easier for small projects.Factors to consider in choosing between monoliths and microservices include cost, team size, and project goals.