Stefan Amann

Senior Backend Architect — Regulated Java & Go Systems Automotive · Healthcare · Energy · Compliance

Germany, Munich Area | Remote worldwide | Occasional travel | Full-time from June 2026 / short notice | Day rate on request

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Hands-on backend architect for systems that pass audit, ship to global rollout, and survive escalation.
Brought in by BMW, Volkswagen Financial Services, and Worldline.

PROFILE

Senior Backend Architect and hands-on Java/Go engineer with 20+ years building regulated backend systems, cloud migration programs, and enterprise platforms across automotive, healthcare, finance, energy, B2B SaaS, and German Mittelstand environments.

Brought into escalated programs where systems must pass architecture review, survive audit, migrate safely, and keep production running. Track record at BMW ConnectedDrive, Volkswagen Financial Services, Worldline, LYNQTECH, and German SME platforms.

Strong fit for senior backend architecture, migration recovery, Java/Spring Boot systems, Go services, regulated integrations, CI/CD modernization, and technical leadership for distributed teams.

BEST-FIT ASSIGNMENTS

Regulated backend systems: gematik telematics (FHIR/KIM/TIM), German e-invoicing and tax (ZUGFeRD/XRechnung, GoBD, FinTS, DATEV), automotive cloud, energy platforms

Recovery of stalled or escalated cloud migration programs, including 2 BMW programs returned to delivery.

Technical leadership for distributed backend teams across Germany, Romania, Spain, and India

Hands-on Java/Spring and Go implementation when the architect also needs to ship code

Legacy modernization and monolith-to-microservice transitions on Kubernetes and OpenShift

Target roles: Senior Backend Architect, Technical Lead, Staff Backend Engineer, Migration Recovery Lead for regulated Java/Go platforms.

SELECTED ACHIEVEMENTS

Led BMW ConnectedDrive Online Entertainment rewrite into Connected Music; 10 developers across Germany, Romania, Spain, India in a 12-person team.

Designed the BMW Online Entertainment backend architecture and secured approval in multiple BMW architecture review meetings.

Made the case for a microservice rewrite of BMW ConnectedDrive Online Entertainment after its lift-and-shift onto OpenShift; secured BMW approval and led delivery to worldwide rollout.

Recovered two escalated BMW cloud migration programs back to delivery: Online Entertainment, then MNO Manager.

Co-founded Lyngual as CTO; built a 5-person IT team in a 12-person company, onboarded translators from 70 countries, launched public beta in 10 months.

Supported Volkswagen Financial Services in a major migration program covering hundreds of applications and thousands of databases, later extended as part of a specialist team for country migrations including UK and France.

Led mybestbrands deployment transformation from manual releases to automated CI/CD; release frequency moved from weekly to multiple deploys per day.

Shipped zero-downtime migration of a fashion platform carrying 3–5M live products with multiple offers and 30M+ archived records.

Owned end-to-end LYNQTECH document workflows and replaced internal print/mailing processes with Deutsche Post API integration.

CORE TECHNOLOGY PROFILE

Backend and Architecture | Java, Spring Boot, Spring Data, Spring Security, Go, REST APIs, OpenAPI, microservice architecture, backend architecture, legacy modernization, API design, distributed systems

Cloud, Platform, DevOps | Kubernetes, OpenShift, Docker, GitLab CI/CD, Jenkins, Drone, AWS, Azure, Nomad, Consul, Vault, CI/CD automation, deployment automation, private cloud, cloud migration

Data and Messaging | PostgreSQL, Oracle, Microsoft SQL Server, MySQL, MongoDB, Redis, Solr/Lucene, Flyway, IBM MQ, ActiveMQ, SMTP, POP3, LDAP

Security and Regulated Systems | OAuth2, JWT, PKI, cryptography, digital signatures, hashing, FHIR, KIM, TIM, FinTS, DATEV export, GoBD audit trails, EN16931, ZUGFeRD, XRechnung, DSGVO/GDPR

Leadership and Delivery | Technical leadership, distributed team leadership, architecture reviews, stakeholder communication, migration recovery, vendor coordination, agile delivery, Kanban, Scrum, production ownership

SELECTED PROJECT EXPERIENCE

Current ERP / CRM / Accounting Platform for German Food Manufacturer

Bauernhof-Eis Stangl GbR | Jan 2026-Present | Sole Architect and Developer | Pre-production

Design and implementation of a compact ERP, CRM, accounting, and production-planning platform for a German food manufacturer. The system replaces Rechnung11, self-built Excel sheets, and manual processes for fewer than 10 internal users.

• Designed and implemented the full platform architecture as sole architect and developer.

• Built modules for customer management, B2B order handling, invoicing, production planning, and accounting support.

• Implemented DATEV export, ZUGFeRD/XRechnung e-invoicing, FinTS bank statement synchronization, and GoBD audit trail concepts.

• Used AI-supported workflows for prototyping, test support, and implementation acceleration while retaining full architecture, review, testing strategy, and technical ownership.

Technology: Java 23, Spring Boot 3, Spring Data JPA, Spring Security, Vue 3, TypeScript, PostgreSQL, Flyway, REST, OpenAPI, JWT, TOTP, RBAC, DATEV, FinTS, ZUGFeRD, XRechnung, GoBD, JUnit, Mockito, Testcontainers, Playwright, Docker, GitLab CI/CD

Secure Communication Gateway for German Healthcare Infrastructure

Worldline Germany GmbH | Jul 2024-Oct 2025 | Backend Engineer

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

Go and Java Microservice Platform on AWS

LYNQTECH GmbH | May 2022-Jun 2024 | Backend Engineer / Software Architect

Backend engineering and architecture for an energy-sector B2B SaaS platform built on Go and Java microservices running on Kubernetes and AWS. Owned end-to-end document workflows. Generation, persistence/archiving, printing, and delivery. Also replaced internal print and mailing workflows with Deutsche Post API integration. Work also covered feature delivery, performance profiling, prototyping, OAuth2/JWT-secured APIs, and CI/CD workflows.

• Built Go and Java microservices for an energy-sector B2B SaaS platform on Kubernetes and AWS.

• Owned end-to-end document workflows covering generation, persistence/archiving, printing, and delivery.

• Replaced internal print and mailing workflows with a Deutsche Post API integration.

• Built REST/OpenAPI service interfaces and OAuth2/JWT-secured authentication flows.

Technology: Go, Java, Quarkus, Spring Boot, Spring Data, REST, OpenAPI, OAuth2, JWT, AWS Aurora, RDS, S3, Cognito, PostgreSQL, MySQL, Kubernetes, Docker, GitHub, Jenkins, Drone

Data Center and Database Migration Program

Volkswagen Financial Services | Jul 2021-Oct 2022 | Java and Database Specialist / Technical Analyst

Specialist support for a major cross-border data center migration program covering hundreds of applications and thousands of databases. Joined the main project in its final third and was later extended as part of a specialist team supporting country migrations including UK, France, and additional subsidiaries.

• Drove migration analysis and troubleshooting across Java applications and Oracle/SQL Server estates spanning hundreds of apps and thousands of databases.

• Resolved failed lift-and-shift migrations that had caused major performance regressions.

• Migrated Java-based Oracle stored procedures from legacy Oracle environments onto a newer Oracle cluster.

• Drove country-migration workstreams with specialist teams across UK, France, and additional VW subsidiaries.

• Analyzed performance regressions after lift-and-shift migrations and supported remediation across application and database layers.

Technology: Java, Oracle, Oracle stored procedures, Microsoft SQL Server, Python, Perl, Tomcat, Linux, Windows Server, Azure, AWS

Java 8 to Java 17 Telematics Migration

n-design GmbH | Feb 2022-Apr 2022 | Backend Engineer / DevOps Engineer

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

Translation Marketplace Platform

Lyngual GmbH | Mar 2020-Feb 2022 | Co-founder and CTO | Company size: 12 | IT team: 5 | 2 countries

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

BMW SIM Card Management Platform Migration

BMW AG via NTT Data | MNO Manager | May 2019-Feb 2020 | Technical Lead | Team size: 7

Technical lead for BMW MNO Manager, a SIM card management system within the ConnectedDrive ecosystem. Assigned after successful recovery of the BMW Online Entertainment cloud migration to bring a second escalated cloud migration program back on track.

• Took over MNO Manager mid-escalation and re-established weekly delivery rhythm with BMW program management within the first sprint cycle.

• Technical Lead for a 7-person team through MNO Manager platform migration and partial backend rewrite.

• Migrated core platform components from legacy hosting to OpenShift private cloud.

• Extended telecom provider integration capabilities after the cloud migration and shipped additional telecom provider integrations for Hong Kong and the USA.

• Coordinated SIM provisioning integration with mobile network operators across multiple regions, including carrier-side technical contacts for Hong Kong and USA rollouts.

Technology: Java EE 7, PostgreSQL, IBM MQ, ActiveMQ, REST, SOAP, PKI, hashing, digital signatures, OpenShift, GlassFish, Jenkins, Scrum, Kanban, private cloud

BMW ConnectedDrive Online Entertainment / Connected Music

BMW AG via NTT Data | Jan 2017-Apr 2019 | Technical Lead / Backend Architect | Team size: 12 | Developers led: 10

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

Fashion Portal Platform Modernization

mybestbrands GmbH | Jan 2014-Dec 2016 | Senior Software Engineer / Architect | Company size: 35 | Engineering team: 6

Led modernization of a high-traffic fashion and lifestyle portal from a monolithic platform to a microservice-based architecture. The platform handled 3-5M live products with multiple offers and more than 30M inactive or seasonal product records.

• Led backend architecture and implementation within a 6-person engineering team.

• Rebuilt the platform from monolith to microservice-based architecture.

• Introduced REST APIs powering web and mobile clients.

• Transformed deployment from manual releases to fully automated CI/CD.

• Improved release frequency from monthly or weekly releases to multiple deployments per day.

• Delivered zero-downtime migration from the legacy platform.

Technology: C#, Java, JavaScript, Python, Bash, Node.js, PowerShell, Spring Boot, Spring Data, Microsoft SQL Server, Solr, MongoDB, Elasticsearch, Azure Service Bus, REST, SOAP, Ansible, Jenkins, Bamboo, Rundeck, Linux, Windows Server, AWS, Azure, GCP

Hotel Booking Platform

Hotel Agenten GmbH | Jan 2011-Dec 2020 | Sole Technical Lead / Software Architect

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

CAREER HISTORY

Period | Role | Company / Location | Focus

Feb 2022-Present | Freelance Backend Architect / Engineer | Germany | Enterprise and SME assignments for Worldline, LYNQTECH, Volkswagen Financial Services, n-design, and Bauernhof-Eis Stangl.

Mar 2020-Feb 2022 | Co-founder and CTO | Lyngual GmbH, Munich / Spain | Built technology team, platform architecture, infrastructure, and delivery process from zero to public beta.

Jan 2017-Feb 2020 | Senior Technical Consultant | NTT Data, Munich | Technical lead and consultant for BMW cloud migration and ConnectedDrive platform projects. Contributed to BMW account growth from EUR 300k to EUR 1.2M annually through technical leadership and project expansion.

Jan 2014-Dec 2016 | Senior Software Engineer / Architect | mybestbrands GmbH, Munich / Croatia | High-traffic fashion portal modernization, backend architecture, CI/CD automation, and deployment transformation.

Jan 2010-Dec 2013 | Software Developer / Architect | Catbird Seat GmbH, Munich | Software development and architecture for web platforms and backend systems.

Jul 2008-Dec 2009 | Software Developer / Architect | Lorenz Software GmbH, Freising | Software development and architecture.

Oct 2007-Apr 2008 | Software Developer | JobScout24 GmbH, Munich | Software development for online recruiting platform.

Apr 2006-Sep 2007 | Military Service | Bundeswehr | Military service including deployment experience.

Sep 2003-Aug 2004 | Software Developer | Webdatabases GmbH, Schwaebisch Gmuend | Software development after completing vocational training.

inet-advice - Stefan Amann

Independent Software Consultant | Aug 2004-Feb 2020, resumed from 2022

Independent software consulting business focused on backend development, software architecture, web platforms, and long-running production systems. Initially operated as a full-time freelance business until military service. Later maintained for selected client projects, profitable web properties, and recurring long-running engagements such as Hotel Agenten. The business was closed before co-founding Lyngual and later resumed when returning to freelance consulting.

EDUCATION AND LANGUAGES

IT Specialist for Application DevelopmentEbit GmbH / ENSECO GmbHCrailsheim, Germany | Sep 2000-Aug 2003Dual vocational training focused on software development, database development, client/server systems, algorithms and data structures, programming methodology, computer networking, and business administration. | LanguagesGerman: NativeEnglish: Fluent professional working proficiency

COMPACT TECHNOLOGY APPENDIX

Primary: Java, Spring Boot, Go, PostgreSQL, REST, OpenAPI, microservices, backend architecture, Kubernetes, OpenShift, Docker, CI/CD, GitLab CI/CD, Jenkins

Secondary: AWS, Azure, MongoDB, Redis, Oracle, Microsoft SQL Server, OAuth2, JWT, PKI, FHIR, KIM, TIM, FinTS, DATEV, GoBD, EN16931, ZUGFeRD, XRechnung, Vue, TypeScript, React, Rust, Nomad, Consul, Vault

Legacy / Context: Java EE, JEE, SOAP, GlassFish, Vaadin, C#, .NET, Perl, PHP, MySQL, Solr/Lucene, Bamboo, Rundeck, Ansible, IBM MQ, ActiveMQ