Lexical, Vector & Hybrid Search with Elasticsearch

This presentation was recorded at GOTO Copienhagen 2025. https://gotocph.com Carly Richmond - Manager at Elastic @carlylrichmond RESOURCES https://bsky.app/profile/carlyrichmond.bsky.social https://twitter.com/CarlyLRichmond https://github.com/carlyrichmond https://www.linkedin.com/in/carly-richmond https://carlylrichmond.medium.com https://carlyrichmond.com ABSTRACT Search is not just traditional TF/IDF anymore! The current trend of machine learning and models has opened another dimension for search. Generative AI, specifically LLMs, continues to dominate news headlines, marking a turning point in building search applications and finding data. Yet, concerns exist about adapting search solutions to perform semantic searches against our private data. This talk gives an overview of traditional lexical search and its limitations. I’ll explain how vector search can be combined with traditional lexical search to form a hybrid approach using Elasticsearch. Finally, I’ll discuss where LLMs come into play with search and how they can be grounded using RAG. […] TIMECODES 00:00 Intro 01:53 1st search engine 03:37 Lexical search 12:57 Vector search 23:14 Hybrid search 27:22 Reranking models 28:59 AI search 35:40 Summary 36:16 Outro Download slides and read the full abstract here: https://gotocph.com/2025/sessions/3606