Technical Skills

I have been developing software for nine years, building everything from the ground up for startups and evolving large-scale distributed systems for major corporations. My current focus is on designing and building (micro-) service architectures using state-of-the-art technologies.

Visualization of a Microservice Architecture.

Backend Frameworks

★ ★ ★★
Spring Boot
Built the first iterations of the neoshare financing platform, as well as the backend of Travacado, an outdoor planning platform.
★ ★ ★
Ktor-Koin Stack
Built an enterprise loyalty system using minimal Jetbrains Ktor and Koin DI stack as part of an 18 month consulting project.
★ ★
Quarkus
Built a system connecting multiple parties via SMS text and Google Dialogflow for a text-only onboarding.

Languages

★ ★ ★ ★
Kotlin
Started with building Android apps and then built various backend systems. Over 5+ years of Kotlin usage since the year it was officially supported by Google.
★ ★
TypeScript
Built the  React-based Travacado frontend from scratch, as well as various express-based cloud functions  (lambdas)
★ ★
Java
Built small-scale transformation processors, Android apps and various university projects in Java. Switched to Kotlin as much as possible in 2017 and thus I am no longer up-to-date.

Databases

★ ★ ★
MongoDB
Persisted structured and semi-structured data for various microservices in different projects. Made use of MongoDB Atlas as a fully-managed  database.
★ ★ ★
PostgreSQL, MySQL
Persisted relational data for various microservices. Mostly used in conjunction with an ORM mapper and Flyway for migrations.

Communication

★ ★ ★ ★
REST APIs
Designed hundreds of REST API endpoints (and previously fluent in OAS (ex. Swagger) specifications).
★ ★ ★ ★
GraphQL
Build a unified query and mutation interface with an underlying modular architecture for all frontend-facing  functionality of Travacado.
★ ★ ★
GCP Pub/Sub
Built numerous publishers and subscribers both with ProtoBuf and JSON. Used various retry policies and dead lettering to maximize resilience.

Testing / Quality

★ ★ ★ ★
Kotest, JUnit
Developed more than 10.000 unit tests over the years and hate to image life without meaningful tests.
★ ★ ★
Gatling
Worked on performance tests for REST endpoints to ensure loads of up to 50.000 requests per second would be executed within SLAs.
★ ★
SonarQube
Introduced SonarQube to multiple projects and a strong believer that it is a good first defence against missing test coverage and code smells.

Observability

★ ★ ★
Datadog
Setup datadog for end-to-end observability from user session recording, to application profiling and metrics.
★ ★ ★
Grafana
Built various custom dashboards for system and service observability in addition to using it on a daily basis as monitoring tool.
★ ★★
Zipkin & Jaeger
Integrated distributed tracing instrumentation in various JVM-based projects for synchronous, JDBC, and asynchronous communication. Used both Zipkin and Jaeger for tracking down issues.

DevOps Tools

★ ★ ★
Kubernetes
Used Kubernetes as managed GCP GKE and AWS EKS services. Configuration in latest project included Flux and Istio and HPA.
★ ★ ★
GitHub Actions
Created and maintained numerous pipelines for quality assurance, builds and deployment.
★ ★
Helm
Created and adapted helm templates in multiple projects.