What is the difference between offline and online LLM evals?
PICTURE THIS: AN LLM TURN
Simple meaning
Offline evals run a frozen set of cases in CI.
WHY — Evals instead of guessing?
Why interviewers care about Evals:
contrast on Evals, not two memorised paragraphs.
the developer, then one case where picking wrong hurts.
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:
- 1Offline evals run a
frozen set of cases in CI.
- 2Online evals measure live
quality with sampling, thumbs, and task success.
- 3How it works
Offline catches regressions before deploy
- 4online catches distribution shift
you never labeled.
- 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
Offline evals run a frozen set of cases in CI. Online evals measure live quality with sampling, thumbs, and task success.