juniorJavaScript
What is async vs sync execution?
Updated May 6, 2026
Short answer
Sync executes sequentially, async executes non-blocking.
Deep explanation
Async allows tasks like I/O to run without blocking main thread.
Real-world example
API requests and timers.
Common mistakes
- Expecting async code to run immediately.
Follow-up questions
- What is the event loop?
- Is JavaScript multi-threaded?