Full-stack software engineer building reliable systems

Who am I

Senior software engineer focused on building backend services that are clear, reliable, and maintainable.

I work primarily on backend services, while also contributing directly to frontend applications and user-facing features.

This site is a small personal project where I share how I build, think, and improve systems.

Sebastiano Fazzino profile picture

About

I’m a senior software engineer with over five years of experience working on production systems.

Most of my work is on backend services: designing APIs, working with data, and keeping systems maintainable, testable and reliable over time.

I’ve worked across iGaming, Fintech, and Crypto, on systems with high throughput, sensitive data, strict security requirements, and multiple external integrations.

Lately I’ve been exploring DevOps and practical AI, mostly by self-hosting, automating deployments, and building small experiments like the assistant on this site.

Experience

Software Engineer — Yolo (iGaming)

Oct 2024 — Apr 2026 · Tallinn

Backend & full-stack · Java / Kotlin · Spring Boot · Angular · MongoDB · PostgreSQL · Redis

I work mainly on a core backend service responsible for player transactions and integrations with external partners. My focus is keeping things reliable in production: data consistency, operational stability, and changes that are easy to reason about.

Java Software Developer — Swag (crypto / fintech)

Feb 2021 — Oct 2024 · Tallinn

Backend · Java · Spring Boot · Kafka · PostgreSQL · GCP · Docker · Kubernetes

I worked on a microservices setup where services communicated over REST and Kafka. Most of my work was on backend systems around payments and order flows, plus integrations with internal and external services.

Certifications

A few courses and certifications I’ve completed recently.

  • Developing Applications with Google Cloud Specialization — Google (Apr 2024)
  • Java Programming and Software Engineering — Duke University (Jan 2023)
  • IBM Data Science Professional Certificate — IBM (Aug 2020)

In progress

  • AWS Solutions Architect — Associate
  • Confluent Certified Developer for Apache Kafka

Projects

Portfolio + AI assistant

Next.js · Kotlin · Self-hosted · PgVector · Lightweight RAG

This site is a small, self-hosted project where I share how I build and iterate on software. It also includes a lightweight AI assistant that can answer questions about my background, experience, and projects using retrieval over curated content.

I built it to show practical system design work: clear boundaries, predictable behavior, and an approach that’s mindful about data safety and operational overhead.

Open Source

The full source code for this project is available under the MIT License. You are welcome to fork it, reuse parts of it, or adapt it for your own portfolio.

→View on GitHub

Connect

You can find me online or reach out directly. I’m always open to thoughtful conversations around engineering, systems, and collaboration.

→LinkedIn→GitHub

I value thoughtful engineering, and keeping things as simple as they can be.

If that aligns with how you work, feel free to get in touch.

Send a message

If you prefer a direct message, you can send one here. It goes straight to my inbox.