Timo Külbel

Senior Fullstack Developer

Bremen, Germany

Experience

Jan 2025 - Present
7 months

Senior Fullstack Entwickler

Project: ZVFutureNow Industry: Banking

In a large banking association, the payment processing systems are being completely redeveloped. As part of my subproject, the payment operations are being rebuilt using stream processing.

  • Design and development of stream processing for international payment transactions based on Kafka and Kafka Streams
  • Development of various input formats for the business domain using Drools rules – dynamically adjusting validation rules
  • Evaluation and comparison of various public cloud providers regarding their database offerings

Team size: 18 Technologies & Tools: Java 21, Kafka, Spring Boot, Google Cloud, SCDF, Kubernetes, PostgreSQL, Drools, Git, S3, MongoDB

May 2024 - Nov 2024
7 months

Senior Fullstack-Developer

Project: International Claims System Industry: Insurance

In an insurance company, all central insurance systems are being redeveloped. My focus in this subproject is on the claims system that handles the processing of damage cases.

  • Development and maintenance of a claims application that is extended per customer based on the Faktorzehn claims system. The technical stack is Java, Spring Boot, and Vaadin.
  • Development of business processes using Camunda
  • Development of asynchronous data interfaces to connected systems using Azure Service Bus
  • Development of Grafana dashboards for production monitoring

Team size: 12 Technologies & Tools: Java 17, Spring Boot, Vaadin, Azure, Argo CD, Kubernetes, PostgreSQL, Camunda, Git, Faktorzehn, Azure Service Bus, Grafana, Octane

May 2023 - Dec 2023
8 months

Team Lead Datenmigration

Project: Data Migration Tools in the Automotive Sector Industry: Leasing

Led development of migration tools for data transfer between multiple systems during the merger of two large leasing companies.

  • Technical Product Owner for data migration tickets
  • Supported management, business design, and business analysis in questions about functional or technical architecture
  • Designed the data migration architecture for two applications
  • Developed and maintained several backend applications and tools for data migration using Spring Boot, Kotlin, and Oracle
  • Lead developer for a 12-member development team

Team size: 15 Technologies & Tools: Kotlin, Spring Boot, Oracle, Azure, Kotlin Exposed, Azure DevOps, Git, Jira

Nov 2022 - Jun 2024
1 year 8 months

Senior Backend Entwickler und Data Engineering

Project: Digital Claims Reporting Industry: Reinsurance

In this reinsurance project, tools are built for claims search, including full-text search. We also create upload tools that let insurance clients submit claims via bulk imports. The submitted data is then transferred to data lakes or within a data mesh.

  • Developed and maintained backend applications using Spring Boot, Spring WebFlux, and Kotlin
  • Built data pipelines with Spark and Scala
  • Optimized analytical queries and full-text searches
  • Managed data workflows using Argo CD
  • CI/CD with Azure DevOps

Team size: 6 Technologies & Tools: Kotlin, Spring Boot, Spring WebFlux, Azure, Cosmos DB, Azure Search, Argo CD, Databricks, Apache Spark, Scala, Azure DevOps, Git

May 2022 - Nov 2022
7 months

Senior Software Entwickler

Project: Colibri Industry: Public Sector

COLIBRI is a payment system for unemployment benefits with an annual payout of about €15 billion. It currently runs on a three-tier architecture (presentation, logic, data) with CORBA and is written in C++. We are replacing C++ with Java.

  • Used Java EE 7 technologies, especially the APIs: EJB, JTA, JAXB, JAX-RS, JPA, CDI, Bean Validation, Interceptors, Managed Beans
  • Developed backend applications, microservices, and REST services
  • Managed complex build processes (Maven, Git, Stash, Jenkins, etc.)
  • Followed architecture and implementation guidelines
  • Met IT security standards
  • Debugged and profiled distributed applications
  • Tested, integrated, and documented the migrated software components

Team size: 14 Technologies & Tools: Java EE 7, EJB, JTA, JAXB, JAX-RS, JPA, CDI, Bean Validation, Interceptors, Managed Beans, Microservices, REST Services, Maven, Git, Stash, Jenkins

Mar 2021 - Jan 2022
11 months

Lead Developer Backend

Project: Social Network Industry: Non-Profit

Developed a social network for a sustainable mobile phone manufacturer.

  • Built the backend component of the social network
  • Integrated the system with Keycloak
  • Developed the back-office GUI for the social network
  • Designed the architecture for future expansion and development of the application

Team size: 12 (backend completely independent) Technologies & Tools: JHipster, Kotlin, Spring Boot, Angular, Keycloak, HATEOAS

Nov 2019 - Mar 2022
2 years 5 months

Fullstack Developer and Product Owner

Project: E-Commerce-Capable Backend Systems in the Automotive Sector Industry: Leasing

Built a fully digital application process for a leasing company, including integration with digital marketplaces.

  • Maintained the digital application flow
  • Designed and developed a leasing and used car offering platform
  • Developed various interfaces to external and internal partners
  • Front-end development of the leasing configuration flow
  • Product Owner for used-car leasing

Team size: 15 Technologies & Tools: Kotlin, Kubernetes, Azure, MongoDB (Cosmos), React, NATS, Redis, Camunda, React, PostgreSQL, Jira, Confluence

May 2019 - Nov 2019
7 months

Technischer Teamlead

Project: Pricing Service Modernization Industry: Leasing

Rebuilt a pricing service as a microservice.

  • Designed, developed, and operated the application
  • Maintained user stories in Jira
  • Developed backend pricing logic
  • Implemented caching strategies for results

Team size: 4 Technologies & Tools: Java, Kubernetes, Azure, MongoDB, Redis

Oct 2018 - Apr 2019
7 months

Senior Software Developer

Project: Notification Component Industry: Shipping Logistics

Enhanced a notification component.

  • Developed and maintained a high-volume customer email notification component (messaging)
  • Created a new push notification component
  • Handled DevOps tasks like CI/CD setup, code, version, and release management

Team size: 8 Technologies & Tools: Java, OpenShift, Google Firebase, JMS, ActiveMQ, Oracle

Apr 2018 - Sep 2018
6 months

Senior Software Developer

Project: Parcel Shop Finder Industry: Shipping Logistics

Rebuilt the parcel shop finder.

  • Designed and developed microservices for parcel shop search
  • Created automated load tests for the parcel shop finder using Gatling
  • Performed DevOps tasks in OpenShift
  • Followed Test-Driven Development (TDD)

Team size: 3 Technologies & Tools: Kotlin, OpenShift, Spring Boot, MongoDB, Grafana, Gatling

Jan 2018 - Present
7 years 7 months

Entwicklung diverser Verwaltungstools für Unternehmen des Mittelstands

Examples:

  • Backend for an online massage booking platform
  • ERP for a plumbing company
  • Warehouse management system for a moving company

Technologies & Tools: JHipster, Kotlin, Spring Boot, Angular, Keycloak, PostgreSQL

Apr 2013 - Mar 2018
5 years

Lead Developer and Java Architect

Project: Fleet Management Software Industry: Automotive

Adapted and enhanced fleet management software for a fleet management service inside a leasing company.

  • Deputy development manager (at the software service provider)
  • Technical project lead for the client
  • Lead developer of a sprint team
  • Security officer for the software
  • Data protection officer (at the software service provider)
  • Responsible for interface development (mainly SOAP, REST), reporting, and business documents
  • Ongoing improvements and bug fixes
  • Created cost calculations in full-service areas
  • Designed functional concepts for travel management billing

Team size: 7 Technologies & Tools: Java, Struts, Hibernate, Oracle, BIRT, SOAP, REST

Jun 2011 - Mar 2013
1 year 10 months

Senior Developer

Project: Claims Management Component Industry: Insurance

Adapted and enhanced a claims management software for car insurance B2B damage notifications.

  • Technical project lead for the client
  • Ongoing improvements and bug fixes
  • Responsible for interface development (mainly SOAP, REST)

Team size: 3 Technologies & Tools: Java, Struts, Hibernate, Oracle, BIRT, SOAP

Jan 2009 - May 2011
1 year 5 months

Senior Developer

Project: International Fleet Management Rollout Industry: Fleet Management

A fleet management company expanded from domestic service to operations in 26 countries for a major international client.

  • Developed various invoice importers
  • Implemented country-specific adjustments in invoice processing
  • Set up CI/CD build processes
  • Used Test-Driven Development (TDD)

Team size: 6 Technologies & Tools: Java, Struts, Hibernate, Oracle, BIRT

Jul 2009 - Dec 2009
6 months

Java Developer

Project: PDF Reports Industry: Credit Reporting Agency

Developed PDF reports (previously only ASCII text reports existed).

  • Created PDF reports using iText
  • Used Test-Driven Development (TDD)
  • Designed the architecture for future extension and development
  • Internationalized the report layouts
  • Styled the PDF reports

Team size: 2 Technologies & Tools: Java, DB2, iText

Jul 2007 - Jun 2009
2 years

Java Developer

Project: Development and Operation of Web Crawlers Industry: Credit Reporting Agency

Built web crawlers in the credit reporting field.

  • Created a press crawler
  • Operated and maintained crawlers for legal notices and company monitoring
  • Developed a frontend for research staff to rate press crawler results
  • Integrated crawler execution into UC4

Team size: 2 Technologies & Tools: Java, DB2, JSF, Lucene, UC4

Nov 2003 - Jun 2007
3 years 8 months

Software Architect

Project: Analytical Campaign Management Industry: Non-Profit

Built a system for analytical campaign management for a non-profit organization.

  • Responsible for software development and architecture of a ROLAP engine for analytical database marketing, focusing on target group segmentation and response analysis
  • Coordinated test management with the client
  • Supported the client’s target group definition within the ROLAP engine
  • Designed the architecture for future extension and development
  • Used Test-Driven Development (TDD)

Team size: 6 Technologies & Tools: Java, Struts, Hibernate, AspectJ, Oracle

E-Commerce für DIY / Textilhandel

Developed an ERP system for multichannel fulfillment. Built and integrated APIs for Shopify, Etsy, and Amazon shops. Set up email integration via SendGrid.

Technologies & Tools: JHipster, Kotlin, Spring Boot, Neo4j, DuckDB, Shopify API, Etsy API, Amazon API, Angular, GraphQL

Languages

German
Native
English
Advanced
Spanish
Elementary

Education

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Diplom‐Wirtschaftsinformatiker · Business Informatics