Search rules engine: pins, diversity and scheduling
Pin exact results to a position, cap how many results from one group can appear together, schedule rules to a time window, and per-key rate limiting.
Search rules landed as a first-class feature: pin specific documents to exact positions in the result set, cap the maximum number of results from a given field value (brand, seller, category) so one source can't dominate a page, and schedule a rule to a start and end time so seasonal changes turn themselves off. API keys used in browser widgets also picked up per-key rate limiting, on top of the existing per-organization quota, so one leaked key can't exhaust an entire account's request budget.