About

Sebastian Stefaniuk

Sebastian StefaniukSebastian Stefaniuk

Software engineer

coding awesomely since 2012
Son, husband, father, brother

  • Ich spreche Deutsch.
  • Mówie po polsku.
  • I speak English.
  • دارم فارسی یاد می گیرم

Background

A bit more about my technical background

  • 2024 - Present

    TriumphTriumph

    Lead Software Engineer

    At Triumph, I lead backend engineering for a distributed payments and invoice factoring platform serving the transportation industry. From designing critical payment systems to spearheading a cross-team Okta IDP consolidation, my work lives at the intersection of complex architecture and high-stakes reliability. I leverage agentic development with Claude Code to sharpen delivery pace, building production-grade services that keep money moving.

  • 2023 - 2024

    TiliaTilia

    Senior Software Engineer

    At Tilia, I had the opportunity to work on different parts of a leading virtual economy backend, which included payment processing, invoicing systems, tax processing, as well as accounting and PII management. The company provides services to power virtual economies using payments, virtual tokens, and in-app purchases in a highly distributed system. My experience included being on week-long on-call shifts responsible for responding to alerts and outages.

  • 2020 - 2022

    Mitek SystemsMitek Systems

    Senior Software Engineer

    In 2020 I wanted to try something new and decided to change direction and move away from web development and into another branch of software engineering. At Mitek Systems in San Diego, I joined the internal tooling team responsible for building tools to help the development of an industry-leading digital identity verification system. This experience allowed me to get a good understanding of a highly available system with strict security and protection of PII data. I also had the opportunity to be a technical lead on a project and mentor fellow team members.

  • 2012 - 2019

    Webitects.com (now out of business)

    Fullstack Software Engineer

    I started my career in 2012 as a Fullstack Web Developer at Webitects.com (now out of business) where I stayed for almost eight years. I spent a lot of time at that company crafting my front and back end skills primarily in .NET (first ASP.NET 4.x, then .NET Core) and various JavaScript frameworks ranging from jQuery to KnockoutJS, to Angular, to ReactJS, and NextJS.

    I have to admit it was a lot of fun learning all the different technologies, and applying good coding practices to a wide range of projects. But the most satisfying aspect was to receive feedback from clients about how useful our work was to what they needed.

Languages

A passion for languages

Spoken and coding languages have some things in common, such as having specific syntax and shortcuts. I was fortunate to grow up in a bilingual household. I was born in Poland to Polish parents, and when I was two years old, my family moved to Germany. Living most of my childhood in quaint villages near Hamburg, I learned the German language, but never forgot Polish.

Then, starting in fitfh grade, English was added to my repertoire of spoken languages. Living in the United States as an adult, I've developed a deep appreciation for the art of multilingual communication, and my gratitude for speaking multiple languages has flourished.

More recently I have started to learn the Persian language after it became apparent that my mother-in-law would not learn English so quickly (giggle).

Projects

Side projects I build because they matter to people I care about

Outside of my day job, I like to challenge myself and learn new things whenever time allows it. Lately that's meant getting into 3D printing and modeling, practicing mindfulness through meditation and cooking, and indulging my long-time love of electronica music and the JDM car scene. But the projects I'm proudest of are the ones where my skills as an engineer meet a real need for people I care about, whether that's my family, my community, or a parent somewhere trying to make better choices for their kid.

LyricsRay

An AI tool born from a dad's gut check

It started with a simple question from my teenage stepdaughter about the lyrics to a popular pop song. When I actually read them, I realized how much questionable content can hide in plain sight in the music kids listen to every day, and how hard it is for parents to keep up. So I built LyricsRay, a free, AI-powered tool that analyzes a song's lyrics for explicit language, violence, substance use, sexual content, and more, and explains what it found in plain language. It doesn't tell anyone what to ban, it just gives parents the information to decide what's right for their family.

LyricsRay is a full-stack project built with Next.js, TypeScript, Claude for the lyrical analysis, and AWS/Terraform for the infrastructure. You can read the full story behind it on my blog.

Built for free, kept free

LyricsRay is intended to be free to use. For now I cover hosting costs, but accept support through Ko-fi, where supporters can donate a small amount as a thank-you. But honestly, the real reward isn't the donations. It's hearing from a parent that the tool helped them have a better conversation with their kid, and that's the kind of impact that keeps me building.

Volunteering for my temple community

An admin portal for the S.R.F. Temple's Sunday School

Most recently, I've been volunteering my time to build an administrative portal for the Self-Realization Fellowship Temple I attend. It handles student registration, class scheduling, attendance, and teacher onboarding for our Sunday School program. It's designed from the ground up to generalize to other SRF Schools and Temples, not just ours, and it's another full-stack effort (Next.js, TypeScript, AWS Lambda, Cognito, DynamoDB, Terraform), giving me a meaningful way to put the skills I use every day at work toward a community that means a lot to me.