Express.js Experts in Germany

• Self-hosted table tennis equipment platform.
• Development of a custom “Racket Builder” that uses a co-evolutionary genetic algorithm to identify, evaluate, and recommend the optimal combinations of racket blades and rubbers based on physics heuristics and player data within a search space of over 4 billion combinations.
• Development of a custom fully automated web crawler to capture equipment specifications, integrating an automated pipeline for image normalization as well as data harmonization via DeepSeek.
• Cloudflare Edge Workers written in Rust to perform low-latency data searches and offload computationally intensive simulations from the main server.
• High performance and accessibility standards across a large Nuxt 4 codebase achieving 95–100/100/100 Lighthouse scores.

• Created complex backend systems (Fastapi Python, GCP cloud functions, APIs, integration tests) using Typescript.
• Worked with firebase and firestore databases, implementing transactional operations, scheduling jobs, and migrations.
• Implemented GCP dashboards for thorough monitoring and custom alerts in case of anomaly traffic.
• Implemented Sentry for better debugging, error tracking and overall monitoring of the Next.js frontend.
• Implemented story tests for UI related testing.
• Implemented Typesense in Python Fastapi backend, for improved text based searching along with typo handlings.

• Designed, built, and launched an internal event planning web application used by over 100 department leads for a large event, despite having no dedicated testing phase.

• Ensured smooth, failure-free operation during first production use, leading to the tool being adopted for future events.

• Automated catering calculations and related workflows, significantly reducing email communication and manual computation effort for meal planning.

• Managed deployment and hosting on a Linux server using Coolify, including application setup and runtime operations.

• Hired and guided a communication designer on UX while independently owning all technical decisions and implementation.

• Further development and operation of a central backend service for providing vehicle inventory for international Mercedes-Benz online shops
• Further development of a reservation service for vehicles as part of the checkout process
• Design and implementation of a highly scalable end-to-end test architecture with a focus on maintainability, reusability, and a high number of automated test cases
• Development of a multi-layer test infrastructure with a strict separation of test logic and access layers
• Development of an initialization and caching architecture to significantly speed up local and CI/CD-based test runs
• Development of an AI-supported review architecture for automated evaluation and quality assurance of end-to-end tests
• Development of a dashboard for consolidated display of a vehicle context across multiple backend systems, including AI-generated summaries and compact case analyses
• Integration and further development of connections to various reservation systems via Apache Kafka and REST
• Design of new microservices and support with architecture decisions
• Risk analysis and design of microservice migrations
• Technologies: Java, Spring, Spring Boot, Gradle, Maven, Apache Kafka, REST, OpenAPI, Swagger, Github, Confluence, CI/CD, Microservices, AI, LLMs

• Complete greenfield rebuild across the whole stack — built AI-native: backend in Go and NestJS, PostgreSQL (CNPG) on K3s with GitOps/Terraform; frontend on Angular 22, zoneless.
• Orchestrated coding agents (e.g. Claude Code, Cursor) across the entire lifecycle — architecture, implementation, testing, reviews, documentation — driven by Specification-Driven Development (SDD).
• “Bruno” — LLM commentator persona backed by RAG and MCP for a personality that stays consistent across all generations (match previews, post-match reports, his own virtual bets).

Angular 22 (zoneless, without Zone.js), Claude Code, Claude Code Skills, CNPG, Cursor, Design Tokens (Spec for Code), Docker, Gherkin, Git, GitLab, GitOps, Go, Google Gemini, Grafana, Hetzner Cloud, K3s, Keycloak, Kubernetes, Lighthouse, LLM Integration, Model Context Protocol (MCP), NestJS, Node.js, NPM, Playwright, PostgreSQL, Prometheus, RAG, REST, Specification-Driven Development (SDD), Structured Outputs, Terraform, TypeScript, Vitest

• Led the end-to-end delivery of enterprise full-stack web applications by driving requirement analysis, solution design, frontend and backend development, database design, API integration, code reviews, team coordination, Agile execution, CI/CD deployments, production support, performance optimization, security implementation, and stakeholder collaboration to deliver scalable, high-quality software solutions.

• Founded an AI-powered scheduling and business-management SaaS for SMBs, owning technology strategy, architecture, product development, UX, billing and go-to-market execution.
• Architected and shipped a multi-tenant platform with REST APIs, RBAC, CRM, billing and notifications, powering the manager dashboard, admin console, booking experience and iOS/Android applications.
• Led and mentored 7 software engineers, 1 DevOps engineer, 1 QA engineer and 1 UX/UI designer, while remaining hands-on across backend, frontend and product delivery.
• Built AI voice and chat agents using Python/FastAPI, OpenAI and Anthropic APIs, RAG, pgvector and tool calling; integrated Twilio, Google Calendar/Meet, Stripe and Firebase.
• Owned production infrastructure and automated delivery across separate environments using Docker, Nginx, GitHub Actions and Grafana; represented the company at accelerators and international startup events.

Selected stack: Python, FastAPI, Node.js, Vue 3, React/Next.js, React Native, PostgreSQL, Redis, Docker

• Developed backend for Audit Management Tool using Node.js/Express with Workday API integration.
• Built secure file handling (PDF, PPT, CSV) with AWS S3 and database support via PostgreSQL, Prisma, and MongoDB.
• Implemented validation, role-based access, and audit trails for compliance and data integrity.

• Designing new apps as well as enhancing and running 29 Angular apps for digital claims in an Nx monorepo
• Maintaining and improving a shared component library with ~300 libraries for multiple product teams
• Migrating all apps to a new design system including its component library and systematic refactoring
• Developing and maintaining the CI/CD pipelines (Jenkins, Azure DevOps, Terraform, AWS)
• Managing releases independently including branch handling, versioning, PR coordination and production deployment
• Implementing and maintaining tracking (Adobe Analytics)
• Ensuring accessibility according to BFSG/WCAG
• Test-driven development (TDD) with Jest and Cypress
• Code reviews, mentoring and setting up best practices in the team
• Technologies: TypeScript, Angular 16-20, RxJS, NgRx, Nx (Monorepo), npm, HTML, (S)CSS, Storybook, Jest, Cypress, Cucumber, Husky, Node.js, Git, AWS, Azure DevOps (Repos & Pipelines), Jenkins, Terraform, TDD, BFSG, WCAG, Nexus, IntelliJ, Adobe Analytics

• Designed and implemented a hybrid recommendation system (content-based + collaborative filtering)
• Built end-to-end ML pipelines including data processing, feature engineering, model training, and evaluation
• Developed RAG-based LLM systems using LangChain and vector databases for semantic search and knowledge retrieval
• Established MLOps workflows with MLflow for experiment tracking, versioning, and deployment readiness
• Implemented deep learning models (computer vision & classification) using PyTorch and TensorFlow

Self-initiated, solo project, in active development

• Full-stack TypeScript app (Nuxt 4, Vue 3, Nitro, Drizzle ORM, PostgreSQL) for running tabletop RPG campaigns, built around a system-agnostic core designed to extend from Pathfinder 2e to other systems without rewrites.
• Deliberate content-ownership model: Live References vs. Owned Content, with publishing modeled as an immutable snapshot rather than a flag, designed for forward compatibility from day one. Namespaced, frozen slugs for collision-safe URLs.
• Data ingestion pipeline importing curated Foundry VTT data into a normalized schema, with version-checking. Library currently holds 1,209 creatures and 1,796 spells (PF2e Remastered content); licensing confirmed clear under ORC/OGL for statblock display.
• Strict TDD workflow (red-green-refactor, vertical slices; Vitest, Playwright, PGlite for fast in-memory DB-integration tests), Architecture Decision Records, a maintained domain glossary.
• Standalone, account-free public tools (Creature Database, Spell Database, Encounter Builder) built to launch ahead of the full campaign/adventure product, as a lower-friction wedge to get real usage sooner. Self-hosted on a Hosteurope VPS.

Stack: Nuxt 4, Vue 3, Nitro, Drizzle ORM, PostgreSQL, Vitest, Playwright, PGlite

• Development of a SaaS platform for esports teams with roles, scheduling, statistics, and billing
• Planning and implementation of the architecture, external API integrations, and operations
• Stack: Laravel 13, React 19, TypeScript, PostgreSQL, Redis, and Stripe

Overall architecture and technical implementation of a Wix-based subscription frontend with Stripe payments and connection to Axxessio's SaaS backend. Implemented Stripe Checkout, subscriptions, webhooks, and transaction logging end to end. Customer data and contract information transferred automatically via a JWT-protected REST API. Designed and documented proxy and security architecture for IP whitelisting, HMAC, and operations, and aligned it with the backend team.

Stack: Wix Studio, Wix Velo, JavaScript, Stripe, Webhooks, JWT, HMAC, REST API, Hetzner, Cloudflare