Real Time Updates easy
For a human user, what is generally considered the maximum acceptable latency for an interaction to feel 'Real-Time' (e.g., typing in a Google Doc)?
- A 1000ms (1 second)
- B 5 seconds
- C ~100-200ms
- D 0ms (Instant)
Answer: C. ~100-200ms
While 0ms is impossible (speed of light), research shows that delays under ~200ms are perceived as instantaneous by the human brain. Above that, users notice lag.
One system design question a day, with spaced repetition so the ones you miss come back.
Get the appRelated questions
- When a mobile app is closed/backgrounded, it cannot keep a WebSocket open. How does it receive real-time alerts (like 'New Message')?
- If you want to update a news feed on a website every time a new article is published, what is the simplest (but least efficient) 'Real-Time' technique?
- In a persistent real-time connection, what is the purpose of a 'Heartbeat' or 'Ping/Pong' message?
- Why is Short Polling considered 'Chatty'?
- Server-Sent Events (SSE) are ideal for which type of real-time application?
- What is the primary advantage of using a WebSocket over standard HTTP for a chat application?