Denver, CO · Principal Software Engineer

Zephan Johnson

I build systems that have to hold up under load — real-time auctions, identity, and the platforms games run on. Lately that includes AI agent pipelines that turn a conversation into a working product.

Zephan Johnson on a rocky coastline, wearing a Sox cap
1M+ QPS on the Unity Ads Exchange
$16M yearly AdMob spend unlocked
33% exchange infra cost reduction
<5 min to a playable generated game

Selected work

Projects from the last decade

Battle Creek Games · 2026

Studio platform

Head of Platform for an 18-person studio. Moved a three-title portfolio onto a server-authoritative backend, shipped store-compliant React Native builds, and cut platform spend by $360k a year while halving AI tooling cost.

  • Go microservices
  • React Native
  • iOS / Android

Unity · 2025

Audience Hub

Led development and architecture for a multi-layer cache identity service powering privacy-first advertising across mobile and CTV. Banner net revenue was up 30%, and key partner spend was up 60%.

  • Identity
  • Caching
  • Programmatic

Unity · 2020–2025

Ads Exchange

Real-time programmatic auctions at 1M+ QPS on Kubernetes in GCP. Cut exchange infrastructure from $90k/day to $60k/day while volume grew 25%. Dynamic floors and consolidated bid requests lifted average bid price more than 8% quarter over quarter.

  • Go
  • GCP
  • Kubernetes
  • Kafka

Unity · 2020–2023

Ad Supply Sync

Designed the refactor of the supply-syncing service that unlocked more than $16M a year in Google AdMob spend. Integrated an experimentation platform so revenue-critical auction changes could ship behind A/B tests.

  • Distributed systems
  • Experimentation

Relativity · 2016–2020

Document Viewer

Green-field single-page refactor of Relativity’s document viewer, including public front-end APIs for custom integrations. Helped launch the company’s first multi-tenant cloud service, converting native files to HTML5 for browser viewing.

  • SPA
  • HTML5
  • Multi-tenant

Experience

Where the work happened

  1. Apr 2026 – Present

    Principal Software Engineer, Head of Platform

    Battle Creek Games

  2. May 2023 – Dec 2025

    Software Engineering Manager, Unity Exchange

    Unity

  3. Mar 2020 – May 2023

    Senior Software Engineer, Ads

    Unity

  4. May 2016 – Mar 2020

    Software Engineer II

    Relativity

  5. 2016

    B.S. Computer Science

    Illinois Institute of Technology