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Projects

A selection of backend projects and professional work focused on scalable services, API design and event-driven architectures.

Job Crawler [source]

A web crawler in Go that discovers job listings across the web and filters them for relevance. Built as a portfolio project demonstrating system design, concurrency patterns and idiomatic Go.

Implements a three-stage pipeline: concurrent page discovery with per-domain rate limiting, composable relevance filtering using generic filter chains, and LLM-based structured extraction via the OpenRouter API.

Highlights

  • Concurrent worker pools with per-domain queuing
  • Atomic URL deduplication with SQLite
  • Generic filter combinators (CheckFn[T])
  • LLM-based structured data extraction
  • OpenTelemetry + Prometheus metrics
  • Retry with exponential backoff

Stack Go · SQLite · OpenTelemetry · Prometheus · OpenRouter API

Focus Concurrency, system design, idiomatic Go

Event-Driven Microservices Platform

Client QRaGo GmbH

Design and implementation of backend microservices for a logistics platform with an emphasis on event-driven workflows and service boundaries.

Architected domain workflows using CQRS-style patterns and event-driven communication between services.

Highlights

  • Microservice architecture design
  • Event-driven workflows
  • CQRS and event sourcing concepts
  • API development for internal and external consumers
  • Production system reliability improvements

Stack Go · Node.js · MongoDB · Redis · Microservices

Focus Distributed systems, architecture design, scalability

Core API Platform

Client jooli.com GmbH

Backend development for core application services including REST APIs, API contracts and automated testing infrastructure.

Established testing strategies and improved development reliability through automated validation pipelines.

Highlights

  • REST API design and implementation
  • OpenAPI specification authoring
  • Automated unit and end-to-end testing
  • Backend architecture improvements
  • Performance and reliability enhancements

Stack Node.js · NestJS · MySQL · Redis · OpenAPI · Testcontainers

Focus API design, backend architecture, quality engineering

GraphQL Integration Layer

Client Weisse Liste gGmbH (via ressourcenmangel GmbH)

Development of backend services and a GraphQL proxy layer to integrate and aggregate multiple external APIs into a unified system.

Highlights

  • GraphQL aggregation layer
  • External API integration
  • Backend service development
  • Data transformation and orchestration

Stack Node.js · TypeScript · Express · GraphQL

Focus API integration, service orchestration, backend design

Additional Experience

Additional freelance and professional work across a range of projects, including backend systems, frontend applications and fullstack product development.

Includes

  • Backend architecture and API development for web platforms
  • Frontend implementation using modern TypeScript frameworks
  • Rapid prototyping for startups and product teams
  • Integration of third-party services and external APIs
  • Collaboration across product, design and engineering teams
  • Performance improvements and reliability enhancements in existing systems

Stack Node.js · NestJS · TypeScript · React · Vue.js · MySQL · NoSQL

Interests

  • Distributed systems design
  • Event-driven architectures
  • Backend reliability and observability
  • API design and developer experience
  • Performance-critical backend services

Availability

Available for backend freelance projects with a focus on:

  • Go backend services
  • Node.js / TypeScript backends
  • System architecture and design
  • API development
  • Performance and reliability improvements

Contact: