About John

John Cairns

I'm John A. Cairns — a software engineer based in Chicago with three decades of experience building distributed software systems. I build in Rust and develop smart contracts for Ethereum; a background in physics and systems programming grounds my work in blockchain, financial engineering, and open source. I appreciate the inherent balance of art and science, and a considered approach in all things.

What I work on

My day-to-day is smart contracts and on-chain trading infrastructure — the systems behind Fabric, a high-performance DEX aggregator. These are production services written in Rust and Solidity that run across multiple chains (Base, Arbitrum, Solana), spanning the full stack of a modern trading platform:

  • Multi-chain pool indexing and quoting — services that snapshot and query liquidity across Uniswap V2/V3/V4-style pools in real time.
  • On-chain swap execution — Solidity execution engines that run off-chain-planned routes (sequences, splits, multi-pool paths) safely on-chain.
  • Token discovery and risk — fast, typeahead-grade token indexing with metadata and risk scoring.
  • Data pipelines — Ethereum log ETL into Arrow/Parquet for archival and real-time indexing, with resilient RPC handling.

I care about correctness, performance, and tools that compose. A few things I've shipped that show how I think:

  • parsm — a structured-data processor for the command line (JSON, CSV, YAML, TOML, logfmt, plain text). A friendlier superset of sed/awk/grep. Published on crates.io.
  • EMOM Timer — a precision, drift-correcting workout timer built in Rust + WebAssembly (Yew). Source.
  • checksmix — a fast emulator and assembler for Knuth's MMIX. A homage to The Art of Computer Programming and the fundamentals it teaches.
  • snipren and trimtrain — small, intent-aware Unix utilities that do one thing well.
  • Conversant Disruptor — a high-performance Java ring-buffer BlockingQueue with ~320 stars, published on Maven Central, packaged for Debian and Ubuntu, and used by Apache Log4j 2 as an async-logging queue.
  • On-chain protocols — author of Collective Governance, an Ethereum voting/consensus protocol, and a contributor to Stader's ETHx liquid-staking protocol.

I work comfortably across Rust, Solidity, Go, C++, Python, and TypeScript, and I keep a set of standardized dev containers so the toolchain is never the bottleneck. I also have a standing interest in zero-knowledge proofs and applied cryptography — Merkle proofs, Fiat–Shamir, ZoKrates and gnark — that I explore in the open as I go.

Illustration & cartography

Away from code, I'm an enthusiastic amateur illustrator, photographer, and computer cartographer. I created the regional maps for six military-history books written by Brian Todd Carey — from Warfare in the Ancient World through the Warfare in the Age of Crusades series — maps that place campaigns, shifting frontiers, and battle sites within their geographic context, presenting complex history through clear, thoughtful cartography.

Beyond the terminal

A proud husband and father of three, I enjoy family time, travel, and the rich tapestry of life in Chicago. On the weekends you might find me on a long run in a forest preserve or at a kid's soccer match. I also bake, play music, and narrate public-domain works for LibriVox.

Find me