Stefan Amann-Senior Backend Architect — Regulated Java & Go Systems

Backend engineering for a production secure-communication gateway connecting German health insurers to the national telematics infrastructure. The system supports regulated medical-data communication and message flows around FHIR, KIM, and TIM.

• Shipped backend features and bug fixes for the gematik telematics gateway connecting German health insurers to TI.
• Built Java/Spring services for FHIR, KIM, and TIM message handling and integration flows.
• Hardened cryptographic message handling (PKI, hashing, digital signatures) across secure communication paths.
• Resolved 5 major production bugs and raised test coverage around secure message processing and integration flows.

Technology: Java, Java EE, Spring, Spring Boot, Spring Data, FHIR, KIM, TIM, REST, SMTP, POP3, LDAP, PKI, cryptography, MongoDB, Kubernetes, Docker, OpenAPI, GitLab, Nexus

Migration of a production telematics application from Java 8 to Java 17, including dependency upgrades, deprecated API remediation, and isolated CI pipeline setup for downstream Java libraries in an air-gapped environment.

• Migrated production telematics app and dependencies from Java 8 to Java 17.
• Resolved Java 17 compatibility issues across 15+ modules, including JAXB removal and JDK-internal reflective access in the crypto layer.
• Designed and built isolated GitLab/Jenkins/Nexus CI pipelines that rebuilt every transitive Java dependency from source for an air-gapped target environment.
• Migrated cryptography code to JCA and Bouncy Castle (AES, ECC, hashing) under the Java 17 upgrade.

Technology: Java, Java 17, GitLab, Jenkins, Nexus, JCA, Bouncy Castle, AES, ECC, hashing

Co-founder and CTO of a translation marketplace connecting customers, agencies, and translators. Built the technology organization, hired and led the IT team, defined the technical architecture, and launched public beta within 10 months from company founding. The platform supported translators from 70 countries and services including translation, proofreading, machine translation, certified translation, and agency portals.

• Built and led a 5-person IT team within a 12-person company across two countries.
• Defined technical strategy, architecture, infrastructure, delivery process, and platform roadmap.
• Designed and delivered a Java/Go microservice architecture for marketplace workflows, matching, orders, language services, agency portals, and payments.
• Integrated Adyen and initially implemented Stripe before provider-side onboarding rejection required removal.
• Established CI/CD, secrets management, private cloud infrastructure, and Kanban-based delivery.
• Launched public beta within 10 months from founding. With buyer-side demand constrained through the COVID period, made a deliberate decision in 2022 to wind down operations and return to freelance backend architecture.

Technology: Java, Go, Rust, React, Spring Boot, Spring Data, PostgreSQL, MySQL, Redis, REST, GraphQL, OAuth2, JWT, Nomad, Consul, Vault, Docker, GitLab CI/CD, Rundeck, Adyen, Stripe, OpenAPI

Technical lead for the BMW ConnectedDrive Online Entertainment migration onto OpenShift and the subsequent rewrite into the Connected Music platform. Joined the program at the start of its escalation, supported the lift-and-shift onto OpenShift private cloud, then made the case for and led a follow-on microservice rewrite to enable new streaming-provider integrations and align with BMW's microservice direction. Provider integrations included Spotify, QQ Music, Napster, and Deezer.

• Led 10 developers across Germany, Romania, Spain, and India inside a 12-person project team.
• Designed the backend architecture for all BMW Online Entertainment components.
• Secured architecture-decision approvals in multiple BMW architecture review meetings.
• Made the case for a follow-on microservice rewrite of the migrated platform and secured BMW approval to execute, enabling new streaming-provider integrations.
• Migrated the platform to OpenShift private cloud; migrated Oracle to PostgreSQL.
• Shipped worldwide rollout across 40+ ConnectedDrive markets with only minimal planned nighttime downtime.
• Drove migration-strategy decisions with BMW central architecture and operations, including Oracle-to-PostgreSQL migration, GlassFish-on-OpenShift deployment, and target service boundaries.

Technology: Java EE 7, REST, SOAP, PostgreSQL, Oracle, Redis, PKI, AES, hashing, OpenShift, GlassFish, Jenkins, OpenAPI, Scrum, Kanban, private cloud

Long-running B2B/B2C hotel booking platform engagement focused on trade-fair accommodation, covering architecture, backend development, operations, support, scraping, data analysis, internal tools, and successive platform rewrites over 10 years.

• Sole technical owner across a 10-year engagement, taking the platform through three major rewrites driven by changing business requirements: legacy Perl → PHP/Drupal → Java → a layered Java API backend with an external frontend partner.
• Owned Hotel Agenten backend architecture, implementation, and production operations as sole technical lead.
• Built booking workflows, internal admin tools, document generation, and back-office features on Java/Spring/MySQL.
• Designed and maintained public REST/Swagger APIs powering B2B partner integrations into the booking platform.
• Coordinated a Polish frontend development partner across the API-layered platform iteration.
• Built scraping and data-analysis tooling; drove monolith-to-headless evolution of the platform.

Technology: Java, JavaScript, HTML, CSS, Vaadin, Spring Boot, Spring Data, Spring Security, MySQL, Lucene, REST, Jenkins, Bamboo, Bitbucket, Rundeck, Linux, Swagger

Software development and architecture.

Military service including deployment experience.

Software development after completing vocational training.