# Perplexity launches Fast Search in Search API

The new tier runs on the custom Rust engine Photon, returning 95% of results within 230 ms and cutting agent task costs by 68%.

- Median latency is 160 ms by Perplexity's benchmarks.
- Fast Search scores 0.24 points lower on relevance and 3 percentage points lower on answer availability on internal long-tail tests compared to the default preset.
- Photon replaces Perplexity's previous open-source retrieval engine across the entire service, lowering internal p99 response times from 800 ms to 65 ms.
- Photon uses 20% fewer serving machines, stores 2.5x as much data per document, and isolates index builds from live query servers.

## Why it matters

Developers building AI agent workflows can reduce search latency and query costs with minor trade-offs in retrieval quality.

## Sources

- [Perplexity: Perplexity launches Fast Search in Search API](https://x.com/perplexity_ai/status/2103184653373014509)

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Summarized by dstilled on 2026-09-24. https://dstilled.ai/story/73d9e397-b8bc-40a4-9f76-47d966519d55