Parallel API Calls in Kotlin: async vs Flow.zip vs Flow.combine (Complete Guide)

🚀 Very Common Use Case in Android: Parallel API Calls in Kotlin

Whether you're loading profile + dashboard + notifications together or fetching multiple endpoints for one screen — parallel execution matters for performance.

In Kotlin/Android, we mostly use these three approaches 👇

• async

➡️ “Start now, collect later.”

Best when you need true parallel execution inside coroutines and want control over error handling and cancellation.

• Flow.zip

➡️ “Wait for everyone, then emit once.”

Use when results must be paired positionally — like page 1 with page 1, page 2 with page 2. Perfect for synchronized emissions.

• Flow.combine

➡️ “Emit whenever anyone updates.”

Use when streams emit independently and UI should update whenever any source changes, like real-time data + cached data.

Read the full article here:

https://medium.com/stackademic/parallel-api-calls-in-kotlin-async-vs-flow-zip-vs-flow-combine-complete-guide-87515bcc57e5