What's the difference between the Options API and the Composition API?

Both are still fully supported in Vue 3, and can even be mixed in the same app.

• Options API: Component logic is defined via options (data, methods, computed, watch, lifecycle hooks). It's approachable for beginners and works well for simpler components since related code is grouped by option type.
• Composition API: Logic is written with reactive functions, usually inside <script setup>, and grouped by feature instead of option type. It scales better for large components and enables reusable composables.

In interviews, avoid framing one as strictly better — Options API is fine for simple components, Composition API shines with complex/shared logic.