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sesigl - Overview

👋 Sebastian Sigl

Staff Engineer @ Adevinta | Open Source Advocate | AI Pioneer | Tech Writer & Speaker

Building scalable systems, mentoring engineers, and pushing the boundaries of AI-assisted development.

🚀 About Me

I'm a seasoned software engineer with 15+ years of experience building and scaling production systems. Currently at Adevinta (Kleinanzeigen), I design and maintain high-throughput backend systems serving 10,000+ requests per second while championing modern engineering practices across the organization.

As a Staff Engineer, I bridge the gap between deep technical execution and strategic product leadership, working alongside product, UX, business, and engineering teams to deliver robust, scalable solutions.

💼 Core Expertise

Backend & Distributed Systems

  • 5+ years designing, building, and maintaining production systems at Kleinanzeigen
  • Architecting services handling 10,000+ requests/second at scale
  • Expert in greenfield development and brownfield system evolution
  • Deep experience with microservices, event-driven architectures, and domain-driven design

Full-Stack Architecture

  • Several years of hands-on React, Next.js, and Astro development
  • End-to-end system design spanning frontend, backend, data, and ML components
  • Ensuring architectural coherence across the entire product stack
  • Keeping pace with modern frontend ecosystems (TanStack, etc.)

Data & Machine Learning

  • Daily work with dbt, Databricks, Airflow, and Python
  • Building retail media systems with advanced search capabilities
  • Data-native approach to system design and product development
  • Bridging the gap between software engineering and data science

Engineering Leadership

  • Mentoring engineers from junior to senior, tech leads to heads-of-engineering
  • Driving team success as a Staff Engineer through technical guidance and collaboration
  • Fostering engineering excellence and best practices across the organization
  • Building high-performing teams through systems thinking and continuous improvement

AI-Driven Development

  • AI Pioneer using AI to accelerate learning depth and breadth while maintaining quality
  • Initiator of n8n adoption groups within the organization
  • Host of Claude Coding Days to democratize AI-assisted development
  • Championing the paradigm shift from AI-assisted to agentic coding

📝 Writing & Speaking

I regularly write about software engineering, architecture, and AI on sebastiansigl.com:

  • System Architecture: Modular monoliths, microservices, and scaling strategies
  • Event Sourcing: Practical patterns for event-driven systems
  • Cloud Infrastructure: Docker, Kubernetes, AWS, and modern DevOps practices
  • AI & Productivity: Leveraging AI for faster, deeper learning and development
  • Data Engineering: Becoming a data engineer, working with modern data stacks

🔧 Tech Stack

Languages: Python, Java, JavaScript/TypeScript, Go, SQL

Backend: Spring Boot, Domain-Driven Design, Event Sourcing, Microservices

Frontend: React, Next.js, Astro, Modern JavaScript Ecosystem

Data & ML: dbt, Databricks, Airflow, Apache Spark, Hadoop

Cloud & Infrastructure: AWS, Docker, Kubernetes, Terraform

Tools & Automation: n8n, Claude, GitHub Actions, GitLab CI/CD

🤝 Open Source & Collaboration

I'm passionate about open source and believe in building technology that empowers others. I'm particularly interested in:

  • Developer Tools & AI Integration: Making AI-assisted development accessible
  • Data Infrastructure: Building robust, scalable data pipelines
  • Engineering Excellence: Patterns, practices, and tools that improve software quality
  • Knowledge Sharing: Documentation, guides, and educational content

Looking to Collaborate On:

  • Projects that push the boundaries of AI-assisted development
  • Open source tools for data engineering and ML operations
  • Developer productivity and engineering effectiveness tools
  • Systems that require end-to-end architectural thinking

📫 Get In Touch

🌱 Currently Exploring

  • Advanced agentic coding patterns and their implications for software development
  • Modern frontend architecture patterns (TanStack, Server Components, etc.)
  • Retail media systems and advanced search technologies
  • Scaling AI adoption in engineering organizations

Open to interesting collaborations and conversations about software engineering, architecture, AI, and building great products.