Natural Language Search for Podcast Episodes

Spotify has introduced Natural Language Search for podcast episodes, moving beyond traditional term-based matching to semantic correlation. This system leverages deep learning, transformer neural networks, and approximate nearest neighbor (ANN) search techniques to enable users to find relevant content using natural language queries, even when exact keywords are not present. The solution involves training dense retrieval models to produce query and episode vectors in a shared embedding space, enabling efficient vector search for retrieval. The system is integrated into the production workflow using the Vespa search engine for offline indexing and online query encoding and retrieval.