Spotify Engineering builds and scales the technology behind the world's most popular audio streaming platform, serving over 500 million users. The team is known for pioneering open-source tools like Backstage, an internal developer portal used by 2,700+ engineers to manage 14,000+ software components, and Voyager, a high-performance nearest-neighbor search library for audio recommendations. It also created Klio for scalable audio data pipelines and XCRemoteCache to slash iOS build times by 70%. These innovations demonstrate Spotify Engineering's commitment to developer experience and data-driven audio innovation.
Spotify researchers evaluated the efficacy of using LLMs to replace human participants in A/B testing, finding that raw LLM predictions captured only 39% of human treatment effects. The study concludes that while LLMs can serve as useful proxies for variance reduction or filtering, they cannot replace human experiments for novel interventions due to untestable assumptions regarding surrogacy and comparability.
Spotify Engineering details the architecture of "Vedder," their internal AI data assistant, which helps employees query petabytes of data across 70,000 datasets by generating SQL queries. The system relies on human-curated data domain "clusters" and explicit expert review of training examples to ensure accuracy and trustworthiness, with experts accepting only 12.5% of automatically proposed question-SQL pairs. Vedder has been used by over 2,100 Spotify employees in over 13,000 conversations since August 2025.
Spotify reports that 99% of its engineers use AI coding tools weekly, leading to a 76% increase in AI-authored pull requests. The company developed 'Honk,' a background coding agent powered by Claude, to handle complex code modifications within its Fleet Management system, significantly accelerating migrations. This shift highlights a change in development bottlenecks from coding to human decision-making, with tools like Backstage providing standardization for both human and AI agents.
