Spring Boot Experts in Dortmund

• 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

• DTO class generator: In-house development of a tool for the automatic generation of classes, functions, and methods for use in .NET Core projects based on SAP Business One Service Layer metadata
• E-invoice import add-on: Development of a SAP Business One add-on / coresuite module for the automated import of ZUGFeRD e-invoices as incoming invoices – with configurable mapping to flexibly control the import logic across four mapping types (DIRECT, SQL, FIXED, EXPR). The add-on is available as a licensed product for SAP Business One customers.

Stack: SAP Business One, SAP Business One Service Layer, coresuite Country Package, C#

Development and evolutionary further development of a highly available, cloud-native microservice and integration architecture for dealer and retail processes in the Porsche Car Configurator.

Responsibilities

• Development of Java-/Kotlin-based backend, API, and integration components (Spring Boot)
• Integration of internal and external systems via REST/OpenAPI, GraphQL, Apache Kafka, and AWS SQS (synchronous and asynchronous)
• Implementation of stable, high-performance communication and data flows in a cloud-native platform architecture
• Processing of structured data formats (JSON, Protobuf, GraphQL schemas) based on existing API patterns
• Performance optimization of distributed microservices with reduced response times and higher operational stability
• Technical tests (unit, integration, and API tests) as well as error analysis in production-like environments
• AWS Infrastructure as Code with Terraform and AWS CDK
• CI/CD automation (build, test, and deployment pipelines) with GitHub Actions
• AI-supported feature implementation (GitHub Copilot Agent)

Label: Kotlin, Java 25, Spring Boot 4, Protobuf, TypeScript, AWS, Terraform, CDK, Apache Kafka, AWS SQS, REST/OpenAPI, GraphQL, JSON, PostgreSQL, Docker, GitHub Actions, Maven, Gradle, JUnit, Mockito, Testcontainers

• Designed and implemented the system architecture for scalable document workflows, improving stability and performance.
• Optimized the login flow with TOTP-based MFA, reducing complexity and login time by 35%.
• Built secure backend APIs for document upload, signing, and management.
• Developed encrypted file handling with AWS S3 pre-signed URLs, ensuring GDPR-compliant data protection.
• Implemented JWT-based role authentication, strengthening access control and overall platform security and reducing code and database complexity.
• Optimized database queries and caching using ORM, reducing API response time by 40%.
• Integrated real-time webhook updates, enhancing workflow transparency and user experience.

• Porsche AG (2018 – 12/2019): Design and development of native iOS apps in motorsport/Formula E (e.g. travel app and enterprise warehouse management with SAP integration) and e-mobility (Porsche Taycan; development of a native Microsoft Excel data export).
• StarFinanz / Sparkasse (05/2019 – 07/2021): Worked on the banking app (FinTS, HBCI, PSD2, Apple Pay); implemented Apple Pay; implemented a new TAN method; worked with the FinTS backend (PSD2); opened bank accounts via app (eID, VideoID, Authada); designed a new, modern banking experience.
• eBay Classifieds and Adevinta (07/2021 – 06/2023): Packaging & Pricing (premium features for business customers): e.g. markdown; company page; advertising options; multi-tenant design system based on SwiftUI and UIKit.
• Maschinensucher (07/2023 – 12/2023): Fullstack mobile (Android, iOS) and backend (PHP, Yii, Elastic Search) development; implemented search agent push notifications, InstantSearch, and modernized the design.
• Bankverlag (02/2024 - Present): Consulting and fullstack development of white-label apps (iOS / Android / Java Spring Boot) for private banks.

• Developed a reporting API with RESTful services and Spring Boot
• LDAP integration
• Migrated services to AWS
• Bootstrap
• Frontend development with Angular 14
• JBoss
• DynamoDB
• S3
• Athena