Stefan W.

Software Engineer

Waterloo, Ontario, Canada

About

Experience

  • Software Engineer at Phantom
    Sep 2024 - Present · 1 yr 10 mos

  • CoinTracker (3 yrs 6 mos)
    • Staff Software Engineer
      Jan 2024 - Sep 2024 · 9 mos

      • Developed a comprehensive transaction model to accurately represent blockchain and centralized exchange transactions, replacing an outdated and inefficient Entry model, thus enhancing scalability and functionality. • Reduced technical debt by leading the migration from the old Entry model to the new Transaction model using a Repository Service pattern, collaborating across teams to ensure smooth implementation. • Enhanced codebase organization, maintainability and developer velocity by educating teams on using the Repository Service pattern and Hexagonal architecture, transforming a disorganized monolith into structured top-level domains with well-defined service interfaces.

    • Senior Software Engineer
      Apr 2021 - Jan 2024 · 2 yrs 10 mos

      • Redesigned the accounting engine using Domain Driven Design principles, improving job duration from 5.5 minutes to 20 seconds and ensuring compliance with various countries' crypto tax regulations. • Facilitated collaboration and mentorship by utilizing pair-programming with tools like Tuple.app to collaborate and mentor engineers in real-time, enhancing team collaboration and knowledge sharing. • Improved Python dependency management by transitioning from requirements.txt to Poetry and integrating Dependabot, enhancing security and ease of dependency updates. • Co-founded an architecture guild to discuss best practices, create new style guidelines, and ensure adherence across teams, fostering a culture of continuous improvement.

  • Shopify (3 yrs 4 mos)
    • Senior Software Engineer
      Jul 2020 - Apr 2021 · 10 mos

      · Provided guidance and mentorship to developers to help improve their architecture and code design skills, as well as provide career advice. · Acted as an architect to lead a distributed team of engineers through the transformation of a product into a platform.

    • Software Engineer
      Jan 2018 - Jun 2020 · 2 yrs 6 mos

      · Architected, developed, and scaled Shopify Flow to hundreds of millions of daily workflow executions and decreased our execution SLO from 24 hours to 2 minutes. · Helped grow the number of workflow creations 212x over the past 3 years using Kafka, MySQL, Redis, and Datadog · Developed the partner integration platform for Shopify Flow which is now used by over 52 Shopify Partners (https://help.shopify.com/en/manual/shopify-plus/flow/connectors) · Maintained very solid reliability of a highly customizable workflow management tool · Redesigned and migrated the MySQL workflow execution storage with over a billion rows to decrease load times from over 60 seconds down to 500ms with zero downtime. · Lead the team in the design and development of multiple architecture prototypes using Kafka, Redis, Mysql, and Rails, one of which surpassed the current production system throughput from 120,000 to 760,000 execution per minute and is live.

  • Software Engineer at Diamond Inc
    Sep 2015 - Jan 2018 · 2 yrs 5 mos

    · Architected and implemented a fast, scalable, and fair task processing system (Node.js, RabbitMQ, and Redis) · Integrated Box, Dropbox, Google Drive, macOS, and Outlook APIs using the above task processing system to sync and index user files and emails for our search application · Act as lead manager for the Canadian office, and supervisor for the co-op student hiring process from applicant to exit interview · Built a file watching process to ensure user files were always in sync with our cloud (AWS S3, Node.js) · Designed and developed file importing on macOS using the cargo design pattern for optimal import speeds (Node.js)

  • Web Developer at Kik Interactive, Inc.
    Jan 2015 - Apr 2015 · 4 mos

    · Using data, designed and implemented a model used to increase retention for new Kik Points users · Made the Kik Points Bot production-ready by implementing the Kik Points Bot offer completion logic and stabilizing communication to the AI layer · Developed the backend for an invite award system used by Kik Points · Created a cron job which analysed and killed all poorly performing live offers · Won the internal company-wide hackathon