Radar with Jeff Kao

Radar with Jeff Kao

From Rust in Production by Matthias Endler

January 8, 2026 · 1h 3m · Episode 40

About this episode

This episode explores the technical journey of building HorizonDB, a specialized database for processing location data at scale, featuring insights on geospatial indexing and the use of Rust.

Radar processes billions of location events daily, powering geofencing and location APIs for companies like Uber, Lyft, and thousands of other apps. When their existing infrastructure started hitting performance and cost limits, they built HorizonDB, a specialized database which replaced both Elasticsearch and MongoDB with a custom single binary written in Rust and backed by RocksDB. In this episode, we dive deep into the technical journey from prototype to production. We talk about RocksDB internals, finite-state transducers, the intricacies of geospatial indexing with Hilbert curves, and why Rust's type system and performance characteristics made it the perfect choice for rewriting critical infrastructure that processes location data at massive scale.

People in this episode

Host: Matthias Endler

Guest: Jeff Kao

Topics covered

  • location data
  • database design
  • geospatial indexing
  • Rust programming
  • performance optimization
  • geofencing
  • technical journey

Keywords

  • location events
  • geofencing
  • HorizonDB
  • RocksDB
  • Rust
  • performance limits
  • geospatial indexing
  • Hilbert curves
  • finite-state transducers

Mentioned in this episode

Organizations: Uber, Lyft

Products: HorizonDB, Elasticsearch, MongoDB, RocksDB

Places: Rust

More episodes of Rust in Production

Explore listener stats, chart rankings, contacts and more on the Rust in Production podcast page.