Design an A/B testing platform for LLM features (prompts, models, retrieval) with trustworthy metrics.

Experimenting on LLM features is hard because the outputs are open-ended and quality is fuzzy. Learn how to assign traffic, pick metrics that are not just engagement, handle variance from non-determinism, and avoid the traps that make a winning variant lose in production.

Updated Aug 2026 · Grounded in real Applied AI Engineer interview loops and written to a senior-engineer editorial bar.