Jakob Külzer

Senior Software Engineer

jakob.kuelzer@gmail.com
Toronto, Canada

Professional Summary

Experienced software engineer with 15+ years of experience operating and developing distributed systems, performance optimization, infrastructure, and fullstack web development. Operations-focused mindset with focus on minimizing system failure modes, reducing operational overhead, and improving code quality.

I like to make things go fast, safely.

Work Experience

Wealthsimple

Toronto, Canada

Mar 2026 - Present

Senior Software Developer, Datastores

Mar 2026 - Present

    Shopify

    Toronto, Canada

    Feb 2015 - Present

    Senior Software Engineer, Database Platform

    Apr 2022 - Present
    • • Implemented automation for Zookeeper ensemble maintenance and cluster migrations
    • • Operating and maintaining Shopify's ZooKeeper fleet; created playbooks, procedures, support for teams writing ZooKeeper clients
    • • Performance improvements on inhouse binlog streaming and filtering engine
    • • Optimized ZooKeeper cache frontend and drastically reduced memory and CPU requirements

    Senior Software Engineer, Data

    Sep 2020 - Apr 2022
    • • Implemented schema diff for data extractor to reduce full imports and save resources
    • • Designed and implemented API data ingestion framework and jobs for all of Shopify
    • • Ingestion pipeline configuration project

    Data Engineer, Data Platform

    Feb 2018 - Sep 2020
    • • Architected and implemented Shopify's new data ingestion tool
    • • Improved stability, code quality, maintainability, and reduced operational toil of existing statement based data extractor

    Software Developer

    Feb 2015 - Aug 2018
    • • Extended and maintained Shopify's RESTful APIs
    • • Frontend development for Shopify's Embedded App SDK
    • • Improvements to webhook platform, authentication layer

    Critical Mass

    Toronto, Canada

    Feb 2011 - Aug 2014

    Senior Software Developer

    Aug 2012 - Aug 2014
    • • Planned and implemented complex multi-language automotive web property
    • • Tech talks on various topics, including continous integration, maven, etc.
    • • Won Critical Mass’ CMVP award for outstanding work

    Software Developer

    Feb 2011 - Aug 2012
    • • Development of complex multi-language, multi-national CMS in the automotive space
    • • Implemented core framework for high performance fully interactive automotive web properties
    • • Custom tooling to streamline developer workflows
    • • Established development best practices including tagged released and automated testing

    Mindblossom

    Toronto, Canada

    Aug 2008 - Aug 2009

    Software Developer

    Feb 2009 - Aug 2009
    • • Microsite Development with Groovy on Grails
    • • Frontend Development with Adobe Flex
    • • Database change management

    Software Developer Intern

    Aug 2008 - Jan 2009
    • • Microsite Development with Groovy on Grails

    OptimaBIT GmbH

    Munich, Germany

    Apr 2005 - Dec 2010

    Freelance Consultant, Security

    Feb 2018 - Present
    • • Security Pentest (blackbox/whitebox)
    • • Code reviews (focus Security)
    • • Instructor for Java and XML
    • • Software development
    • • System administration (Linux)

    Technical Skills

    Languages

    Go Ruby Scala Java Elm Zig and more...

    Technologies

    Kubernetes Relational Databases Apache Zookeeper Apache Spark Linux TCP/IP Networking Git

    Education

    Bachelor of Science in Computer Science

    Fachhochschule München

    2007 - 2009