Jon Gjengset is one of the most recognizable names in the Rust community, the author of Rust for Rustaceans, a prolific live-streamer, and a long-time contributor to the Rust ecosystem. Today he works as a Principal Engineer at Helsing, a European defense company that has made Rust a foundational part of its engineering stack. Helsing builds safety-critical software for real-world defense applications, where correctness, performance, and reliability are non-negotiable. In this episode, Jon talks about what it means to build mission-critical systems in Rust, why Helsing bet on Rust from the start, and what lessons from his years of Rust education have shaped the way he writes and thinks about production code.
About Helsing
Founded in 2021, Helsing is a European defence company building AI-enabled software for some of the most demanding environments imaginable. Helsing's software runs where correctness is non-negotiable. That philosophy led them to Rust early on and they've leaned into it fully. From coordinate transforms to CRDT document stores to Protobuf package management, almost everything they build ends up being written in Rust.

About Jon Gjengset
Jon holds a PhD from MIT's PDOS group, where he built Noria, a high-performance streaming dataflow database, and later co-founded ReadySet to continue that work commercially. He then spent time building infrastructure at AWS, before joining Helsing as a Principal Engineer. Outside of his day job, he's been teaching Rust to the world through his livestreams and writing for years, which makes him a rare combination: someone who thinks deeply about both how to use Rust and how to explain it.
Links From The Episode

• Helsing AI selected for Eurofighter upgrade - Helsing's Eurofighter Project
• CA-1 Europa - Helsing's Autonomous Uncrewed Combat Aerial Vehicle
• Rust in Python cryptography - Rust being used in a Python library
• Clippy Documentation: Adding Lints - How to add custom lints to (your own fork of) clippy
• anyhow's .context() - Use it everywhere, it's very very helpful
• eyre - A fork of anyhow with support for customizable, pluggable error report handlers
• miette - Fancy, diagnostic-rich error reporting for Rust with source snippets and labels
• buffrs - Helsing's Cargo-inspired package manager for Protocol Buffers, written in Rust
• sguaba - Helsing's Rust crate for type-safe coordinate system math, preventing unit and frame mix-ups at compile time
• Sguaba: Type-safe spatial math in Rust - Jon's talk at Rust Amsterdam introducing sguaba and the type-system techniques behind it
• Apache Avro - A compact binary serialization format for streaming data, with a Rust implementation available via the apache-avro crate
• pubgrub - A Rust implementation of the PubGrub version-solving algorithm, as used in Cargo and uv
• CRDTs - Conflict-free Replicated Data Types: data structures that can be merged across distributed nodes without conflicts
• ADR (Architecture Decision Record) - A lightweight way to document important architectural decisions and their context
• DSON: JSON CRDT using delta-mutations for document stores - The 2022 paper that was the basis for Helsing's CRDT implementation
• dson - Helsing's Rust implementation of DSON
• Jon's Livestreams on YouTube - Deep-dive Rust coding sessions where Jon implements real-world libraries and systems from scratch
• WebAssembly with Rust - The official Rust and WebAssembly book, covering a cool technology and useful skills to have as a Rust developer
• Rust for Rustaceans - Jon's book for intermediate Rust developers covering ownership, traits, async, and the finer points of the language
• CVE-2024-24576: Cargo/tar supply chain vulnerability - A security issue in the tar crate that affected Cargo's package extraction
• Wikipedia: Defence in Depth - The security principle of using multiple independent layers of protection; Even with Rust you need multiple layers, there is no silver bullet
• SBOMs (Software Bill of Materials) - A machine-readable inventory of all components in a software artifact; Cargo's lock files make this tractable for Rust projects
• Helsing: AI-assisted vetting of software packages - Make it more efficient to review dependencies you take in
• Bevy - A game engine built entirely in Rust, and a notable example of a large, complex Rust dependency
• Tauri - A Rust-powered framework for building lightweight desktop and mobile apps from a web frontend, an alternative to Electron

Official Links

• Helsing Website
• Helsing Tech Blog
• Helsing on GitHub
• Helsing on LinkedIn
• Jon Gjengset's Website
• Jon Gjengset on GitHub
• Jon Gjengset on YouTube
• Jon Gjengset on Bluesky
• Rust for Rustaceans