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Selected Projects

The following are representative projects I’m permitted to showcase. My broader portfolio includes numerous other engagements across different sectors, which, due to confidentiality agreements and business sensitivity, cannot be disclosed in any detail.

Vattenfall – EV Charging Platform Migration

Led the strategic migration to a distributed architecture for Vattenfall’s electric vehicle charging platform. 

Techniques/Tools
:

Java 11, Kotlin, Groovy, Spring (Boot, Cloud, Security, MVC, and more), Spock, Feign, Resillience4J, Vavr, Gradle, Kubernetes, Apache Kafka, DDD, EventStorming, Event Sourcing, CQRS, PostgreSQL, CosmosDB

Impact:

Achieved high operational and delivery efficiency with multiple daily production deployments, improved SLA and TTM, raised developer competencies, and created an attractive workplace that significantly reduced recruitment costs. The solution runs on a public cloud.

My responsibilities:
 

  • Designing the system architecture (~30 microservices) and applications
     

  • Coordinating architectural guild efforts across multiple teams
     

  • Implementing the new platform and gradually phasing out legacy components
     

  • Automating the development pipeline, introducing shared CI/CD processes and contract testing
     

  • Mentoring development teams in agile processes, software craftsmanship, testing (TDD, CDC), tactical DDD, and architecture patterns (CQRS, Event Sourcing) using modern tools such as Java, Kotlin, Spring, Kafka, PACT, and Spock

UK FinTech Company – System Overhaul

Led the architectural redesign of a high-volume FinTech platform specializing in mass payments and currency exchange.


Techniques/Tools:

Java, Kotlin, Spring, Kafka, PACT, Spock, CQRS, Event Sourcing, 

Impact:
Enabled the company to significantly streamline its system architecture, leading to reduced operational risks, enhanced auditability, and improved strategic alignment, ultimately accelerating the transition to a more efficient and maintainable technology landscape.

My responsibilities:
 

  • Designing a target architecture (20+ components) while mentoring developers and architects
     

  • Reducing TTM, operational costs, and manual processing
     

  • Increasing system auditability and reliability
     

  • Developing a migration roadmap from legacy distributed monolith systems
     

  • Advising on domain-team alignment and delivery optimization strategies including automation, contract testing, and documentation

Global Logistics Company – Architectural Transformation

Supported the strategic transformation of a global logistics firm (~10,000 employees).

Techniques/Tools:

Java 17, Groovy, Spring (Boot, Cloud, Security, Web, and more), Spock, Kubernetes, Apache Kafka, DDD, EventStorming, CQRS, PostgreSQL​

 

Impact:

Delivered scalable multi-tenant applications managed by fully autonomous teams, backed by reusable platforms. The team achieved the highest delivery and operational performance in the company (DORA metrics).​

My responsibilities:
 

  • Designing the target system architecture (120+ components) to reduce TTM and error rates
     

  • Creating a migration strategy from a distributed monolith (including major legacy systems) to the new architecture
     

  • Advising on team responsibilities and system domain ownership
     

  • Hands-on leadership in one area: building new applications and establishing modern development standards such as:
     

  • Modular application architecture
     

  • Automated deployment pipelines
     

  • Monitoring platforms with custom metric and alert capabilities
     

  • Application-level tracing (OpenTelemetry)
     

  • End-to-end product lifecycle ownership by development teams

Scandinavian Marketing Company – Ad Efficiency Platform

Designed and implemented a microservices-based system (10+ components) supporting ad campaign sales and performance measurement.

 

Techniques/Tools:

Java 8, Groovy, Spring (Boot, Cloud, Security, MVC, and more), Spock, Netflix Stack (Eureka, Hystrix, Turbine, Sleuth, Zuul, Feign), Spark, Maven, ELK, Grafana/Graphite, PostgreSQL, MongoDB, Cassandra

Impact:
Significantly improved platform reliability, operational efficiency, and deployment speed, establishing foundational infrastructure and processes that enabled better scalability and maintainability of the marketing technology stack.

 

My responsibilities:
 

  • Architecture and development of the platform core (service discovery, load balancing, API gateway, tracing, logging)
     

  • Deployment automation

© 2025 by Bartek Słota.

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