Stefan Wrobel, Software Developer in Los Angeles, CA, United States
Stefan Wrobel

Software Developer in Los Angeles, CA, United States

Member since May 12, 2017
Stefan is a freelance CTO with an MBA. He has founded five startups, as well as freelanced for dozens, for which he has written the initial code and then built out and led the teams to scale as necessary. His talents range from hands-on-development and code reviews to leadership, process development, management, and strategic planning and architecture.
Stefan is now available for hire




Los Angeles, CA, United States



Preferred Environment

PostgreSQL, Ruby on Rails, Heroku, Git

The most amazing...

...thing I've done was rapidly scale StackCommerce to over 10 million monthly visitors as we powered eCommerce for brands like Wired, CNet, Gizmodo, and Mashable.


  • Chief Technology Officer

    2014 - PRESENT
    • Developed early Rails/PostgreSQL architecture at PeerStreet (backed by Andreesen Horowitz); used the highest standards for financial data security and set this early-stage startup for scale that they have since achieved (raised $100+ million).
    • Served as interim CTO and chief architect of the CurbStand valet parking platform, built with a Rails/PostgreSQL back end, native iOS/Android apps, and Braintree for payments.
    • Built a 5-person development team in less than two weeks to replace CurbStand's agency and development back on schedule.
    • Acted as an interim CTO at RallyBound (acquired by NeonOne), implementing processes including daily standups and weekly sprint planning meetings with product/engineering, as well as coding standards and JIRA story creation/culling.
    • Built a hybrid email/web notification system for CodeWars with Rails, MongoDB, and JavaScript.
    Technologies: Ruby on Rails, PostgreSQL, React, Stripe, Braintree
  • Co-founder and Chief Technology Officer

    2017 - 2018
    • Built a secure payments platform with Rails/React/Stripe to allow the California Parent-Teacher Association (CAPTA) members to join electronically (previously they only collected cash and check payments).
    • Integrated into a variety of legacy systems to make sure TOTEM worked smoothly with their existing processes and allowed for consolidated reporting.
    • Worked directly with local CAPTA leaders to roll out the platform state-wide for the 2017-2018 school year, proving on-call support via phone, email, and live chat.
    Technologies: Ruby on Rails, PostgreSQL, React, Stripe
  • Interim CTO

    2017 - 2017
    • Worked with a data scientist to transform a standalone Python script for customer live chat sentiment analysis into a real-time platform to connect to major live chat platforms.
    Technologies: Python
  • Co-founder and Chief Technology Officer

    2013 - 2014
    Cult Cosmetics
    • Built and deployed high-performance microservices with Elixir.
    • Built the initial Ruby on Rails/MySQL/Spree Commerce website and scaled to $1 million ARR using Braintree payments and custom integrations with third-party logistics providers.
    • Built and released a variety of open-source Spree plugins, including the first for subscription commerce.
    Technologies: Ruby on Rails, MySQL, JavaScript, Braintree, Elixir
  • Co-founder and Chief Technology Officer

    2011 - 2012
    • Built StackCommerce, the #1 native commerce platform with AWS/Rails/PostgreSQL.
    • Scaled StackCommerce to 12 employees, $5 million ARR, 150,000 active users, 30 million monthly impressions, and consistent profitability in less than 1 year.
    • Contributed to raising seed funding from a number of institutional and angel investors for StackCommerce (formerly StackSocial), accelerated by AmplifyLA.
    Technologies: Ruby on Rails, PostgreSQL, JavaScript


  • Meta Surf Forecast (Development)

    An open-source, Ruby on Rails/React/Highcharts application to combine the major surf forecasting services into one unified surf forecast (like Metacritic or Rotten Tomatoes, but for surfing). This is a passion project of mine and has been open-sourced on GitHub.

  • How to Think Like a Computer Scientist: Learning with Python (Other amazing things)

    Edited the first edition of the first free, online Python book. Converted the original LaTeX source to HTML and published it to the web.


  • Languages

    Ruby, SQL, HTML, SCSS, JavaScript, CSS, ECMAScript (ES6), ES7, Haml, Sass, HTML5, CSS3, Elixir, TypeScript, Python, Python 2, Python 3
  • Frameworks

    Ruby on Rails (RoR), Ruby on Rails 5, Slim, Ruby on Rails 3, Ruby on Rails 4, Bootstrap
  • Libraries/APIs

    Stripe, Stripe API, Stripe Connect, Stripe Connect API, jQuery, REST APIs, React, Braintree API, Node.js
  • Tools

    Git, GitHub, Spree, Braintree SDK, GitLab, Bitbucket
  • Paradigms

    Requirements Analysis, Database Design, Testing, Web Architecture
  • Platforms

    Heroku, AWS EC2, Amazon Web Services (AWS), Google Cloud Platform (GCP), iOS
  • Industry Expertise

    eCommerce, Web Development
  • Storage

    Database Architecture, PostgreSQL, MySQL, AWS S3, AWS RDS
  • Other

    Ruby on Rails 6, eCommerce APIs, Stripe Payments, Architecture, System Architecture, System Architecture Design, Requirements, Requirements & Specifications, Technical Leadership, User Requirements, Business Requirements, System Requirements, RESTful APIs, Open-source Software, Spree Commerce, Back-end, Full-stack, eCommerce Platforms, BrainTree, AWS


  • MBA in Entrepreneurship
    2006 - 2009
    University of California, Los Angeles - Los Angeles, CA
  • Bachelor of Science degree in Information and Computer Science
    2000 - 2004
    University of California, Irvine - Irvine, CA

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