Hey, I’m Justin.#
I build engineering teams that ship reliably without burning out.
I’ve spent more than a decade as a founding engineer at multiple companies, building the teams and culture from zero and taking them through acquisition. That means clear processes, honest estimation, rituals that earn their keep, and a definition of “done” that actually means done. That’s what the Dev Handbook is about.
Projects#
Warden Authentication - Maintainer of the open-source Ruby authentication library. Warden is the standard in Ruby on Rails authentication with more than 125 million downloads. It powers authentication for millions of users every day.
Heads Down - A SaaS platform I built to manage workplace interruptions from Slack. It lets users focus on the task at hand and communicate response times with coworkers when they’re busy. Native clients built with Swift (iOS) and Flutter/Kotlin (Android), with an Elixir + LiveView backend.
Experience#
Senior Staff Engineer at Shopify
Rotated across 8 teams in Growth (30 to 50 engineers each), brought in to raise the bar on technical direction, architecture, and engineering culture. Balance long-term platform investments against short-term product needs to capture market opportunities.
- Led Shopify’s first pricing change in company history, coordinating engineering, product, and business teams to ship without disruption and drive millions in additional revenue.
- Architected an entitlements system that now powers authorization for all Shopify customers and their contracts, eliminating thousands of developer hours of manual authorization logic.
- Redesigned the billing system to operate across global markets.
- Transformed Customer Support systems with an AI-first architecture.
- Elevated engineering quality and delivery pace in every team through hands-on mentorship and process change that stuck after moving on.
Principal Software Engineer at Red Canary
Built tooling for Fortune 500 companies to detect and combat real-time threats. The platform reliably processed over a petabyte of data per day.
- Founded two internal teams: Application Security and Developer Tools.
- Scaled engineering architecture and processes from 180 to 400 people in a single year.
- Reduced deploy times from 35 minutes to 3 minutes.
- Launched continuing-education programs to improve engineering quality and retention.
- Established coding standards and pull request review processes across the organization.
Principal Software Engineer at Enzyme (YCombinator)
Built a regulatory and compliance system for the pharmaceutical and medical device industries to streamline FDA approval.
- Built a new backend in Elixir using CQRS and Event Sourcing to meet compliance requirements and eliminate tracing issues with the existing system.
- Coordinated with a globally distributed engineering team to prioritize work.
- Replaced a broken Agile system with an engineering process that aligned with the founder’s delivery goals.
Senior Software Architect at Keyp GmbH
Designed a system that lowered the cost of identity verification in the EU by 80% while eliminating the security risk of storing identity-related information on company systems.
- Relocated to Munich, Germany to work directly with the founding team.
- Advised the founders on startup growth, scaling, fundraising, and North American market expansion.
- Guided the company through staffing and employee-structure hurdles.
- Shipped multiple application MVPs using Ruby, Elixir, and Elm when the company was working through traction and funding challenges.
Data Team Lead at Homebot
Fifth employee and first engineering hire. Homebot processed 30 years of public records to build custom estimation models, allowing homeowners to maximize the wealth in their homes without giving away personal information to private companies.
- Built the engineering team and culture from scratch.
- Retained 100% of hires and recruited 6 engineers from my personal network.
- Architected a zero-downtime migration from Node.js to Rails for better stability and performance.
- Built ETL pipelines using Go and Spark for analysis of real estate records.
- Rolled out code analysis and syntax checking tools across the team.
- Promoted to Data Team Lead after 8 months to own all data ingestion and analysis.
VP of Engineering at AgilData
Took over a struggling 8-year-old startup pivoting to compete in the Big Data sector against Apache Spark and Hadoop using an in-house Java-based SQL data store.
- Overhauled engineering practices to align with the new CEO’s goals.
- Built a customer-facing system for tracking feature requests on the product roadmap.
- Led all people management inside Engineering.
- Stood up HR and payroll systems to enable a fully remote company.
Technical Director at NCC Group
First engineer hired at Artemis (acquired by NCC Group) to launch the .trust security-focused gTLD. Designed the engineering organization and architecture to meet ICANN compliance requirements for the .trust domain. Every domain was scanned in real-time for security vulnerabilities and locked down within seconds to prevent attacks.
- Hired by Alex Stamos to build the engineering team at Artemis, spanning software architecture, project management, and recruiting.
- Promoted to Technical Director after one year.
- Managed 8 direct reports and provided technical direction for 16.
- Built a hybrid engineering team across 3 offices with full-time remote employees.
- Built domain registrar, registry, and certificate issuer systems using Ruby and Go.
- Designed a system architecture resilient to nation-state attacks, mitigating the potential for zero-day exploits.
Founder of Mongo Machine
Built a SaaS business specializing in customized high-availability deployments of MongoDB. Bootstrapped to profitability as a solo founder and acquired by Compose in 2011. Compose was later acquired by IBM.
Education#
B.S. Computer Science, University of Iowa
All thoughts and opinions on this site are my own. They do not represent Shopify or any other employer.
About this site#
This blog covers engineering topics from career management to programming techniques. Most of the content is focused on Elixir, Ruby, and the tools and practices that make remote teams work.