Photon: Building a Retrieval and Ranking Engine From Scratch
Perplexity, Thursday, September 24th, 2026
Perplexity built Photon, a Rust-based retrieval and ranking engine that returns 95% of search results in under 230ms.
Perplexity's engineering blog details Photon, a new Rust-based retrieval and ranking service built from scratch by a small team of engineers and AI agents.
The system separates index building from query serving and uses specialized data formats and batched reads to cut latency. Photon returns 95% of search results in 230 milliseconds or less, a significant speed improvement aimed at supporting AI-native, agentic search experiences.