Why do load balancers need sticky sessions for some WebSocket setups?
PICTURE THIS: A REST CALL
Simple meaning
HTTP long-polling fallbacks and in-memory socket state expect the same client to hit the same process.
WHY — WebSockets instead of guessing?
Why interviewers care about WebSockets:
on WebSockets.
the situation, the default choice, and one exception - that reads as experience.
Name the idea, why it exists, then one short example.
End with when you use it and one common pitfall.
STEPS — What happens step by step?
Before you speak the answer, walk the interviewer through these steps:
- 1HTTP long-polling fallbacks and
in-memory socket state expect the same client to hit the same process.
- 2Why it exists
Sticky sessions pin that client.
- 3With a Redis adapter
and true WebSockets you can often avoid stickiness, which is healthier for scaling.
- 4Give an example
One tiny concrete case you can say aloud.
- 5Common mistake
What juniors usually get wrong.
- 6Close
When you pick this over the alternative.
EXAMPLE — See it in action
Here's a short line you can speak, broken into clear beats:
Note: Adapt this scaffold to your own project — keep it under 60–90 seconds.
Key takeaway
HTTP long-polling fallbacks and in-memory socket state expect the same client to hit the same process. Sticky sessions pin that client.