Search architecture revamp

This post details the revamp of Grab's search architecture from a legacy text-matching system to a multi-layer approach including boosting, multi-recall, and ranking. Key improvements include intent recognition, context consideration, effective blending of results from multiple business verticals, and a modularized plugin-based implementation to enable quick iteration and reuse of components for new search use cases. The new architecture supports embedding-based recall and a mixed Ads/organic framework.