Timo Külbel - Senior Fullstack Developer in Banking

🚀 FRATCH GPT 2.0 - Find freelancers with a single prompt. Now including price benchmarking.

Recommended expert

Bremen, Germany

Check rate

Experience

Jan 2025 - Present

1 year 9 months

Senior Fullstack Developer

Lead Developer / Tech Lead in a large banking group for a complete redevelopment of payment systems
Rebuilding payment processing in stream processing
Development and design of cross-border payment stream processing based on Kafka and Kafka Streams
Development of different input formats for the business team using Drools rules to dynamically adjust validation rules
Evaluation and comparison of different public cloud providers regarding the databases they offer
Technologies & Tools: Java 21, Kotlin, Spring Boot, Kafka, Kubernetes, Azure, TDD, JEE, REST, Angular, Spark, Google Cloud, SCDF, PostgreSQL, Drools, Git, S3, MongoDB

May 2024 - Nov 2024

7 months

Senior Fullstack Developer

Development and support of a claims application based on the Faktor Zehn claim system with 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
Role as Product Owner and Data Protection Officer
Team size: 12
Technologies & Tools: Java 17, Spring Boot, Vaadin, Azure, ArgoCD, Kubernetes, PostgreSQL, Camunda, Git, Faktorzehn, AzureServiceBus, Grafana, Octane

May 2023 - Dec 2023

8 months

Team Lead Data Migration

Technical Product Owner for data migration tickets
Support of management, business design, and business API analysis for functional and technical architecture questions
Creation of the data migration architecture for two applications
Development and support of several backend tools for data migration using Spring Boot, Kotlin, and Oracle
Lead Developer for a development team of 12
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 Developer and Data Engineering

Development and support of backend applications using Spring Boot, Spring WebFlux, and Kotlin
Development of data pipelines using Spark and Scala
Optimization of analytical search queries and full-text searches
Development and support of data workflows using ArgoCD
CI/CD using Azure DevOps
Team size: 6
Technologies & Tools: Kotlin, Spring Boot, Spring WebFlux, Azure, CosmosDB, Azure Search, ArgoCD, Databricks, Apache Spark, Scala, Azure DevOps, Git

May 2022 - Nov 2022

7 months

Senior Software Developer

Migration of a C++-based CORBA payment process for unemployment benefits (approx. €15 billion annual payout) to Java EE 7
Development of backend applications, microservices, and REST services with Java EE 7 APIs (EJB, JPA, JAX-RS, CDI)
Use of complex build processes (Maven, Git, Stash, Jenkins)
Debugging, profiling, testing, integration, and documentation of 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, Maven, Git, Jenkins, Mockito, Wiremock, Gatling

Mar 2021 - Jan 2022

11 months

Lead Developer Backend

Development of the backend component for a social network for a sustainable mobile phone manufacturer
Integration of the system with Keycloak
Development of the back-office GUI for the social network
Planning the architecture for extending and further developing the application
Team size: 12
Technologies & tools: JHipster, Kotlin, Spring Boot, Angular, Keycloak, HATEOAS

Nov 2019 - Mar 2022

2 years 5 months

Fullstack Developer and Product Owner

Building a fully digital application process for a leasing company and integrating it into marketplaces
Support and further development of the digital application process
Design and development of a leasing and used-car offer platform
Development of various interfaces to external and internal partners
Frontend development of the leasing configuration process
Product Owner for used-car leasing
Team size: 15
Technologies & tools: Kotlin, Kubernetes, Azure, MongoDB (Cosmos), React, NATS, Redis, Camunda

May 2019 - Nov 2019

7 months

Technical Team Lead

Design, development, and operation of a pricing microservice
Maintenance of user stories in Jira
Development of the backend pricing logic
Development of caching strategies
Team size: 4
Technologies & tools: Java, Kubernetes, Azure, MongoDB, Redis

Oct 2018 - Apr 2019

7 months

Senior Software Developer

Further development of a notification component for customer emails in a high-load scenario
New development of a push notification component
Performing DevOps tasks: CI/CD, 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

New development of a parcel shop finder with microservices
Creation of automatic load tests for the parcel shop finder with Gatling
DevOps tasks within OpenShift
Development using Test Driven Development
Team size: 3
Technologies & tools: Kotlin, OpenShift, Spring Boot, MongoDB, Grafana, Gatling

Jan 2018 - Present

8 years 9 months

Freelance Developer

Development of various admin tools for medium-sized companies (e.g. backend for the booking platform Onlinemassage, ERP for a plumbing company, warehouse management system for a moving company)
Development of an ERP system for multichannel supply for DIY and textile retail with API connections to Shopify, Etsy, and Amazon, as well as email integration via SendGrid
Technologies & Tools: JHipster, Kotlin, Spring Boot, Angular, Keycloak, PostgreSQL, Neo4J, DuckDB, GraphQL

Apr 2013 - Mar 2018

5 years

Lead Developer and Java Architect

Customization and further development of fleet management software for building up a fleet management service company
Deputy development lead at the software provider
Technical project lead for the client
Lead developer of a sprint team
Security and data protection officer
Responsible for interface development (SOAP, REST), reporting, and business printouts
Further development, bug fixing, and full-service calculations
Business concept 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

Customization and further development of claims management software for B2B car insurance
Technical project lead for the client
Responsible for interface development (SOAP, REST)
Team size: 3
Technologies & Tools: Java, Struts, Hibernate, Oracle, BIRT, SOAP

Jan 2010 - May 2011

1 year 5 months

Senior Developer

International rollout of a fleet management solution in 26 countries
Development of various invoice importers and country-specific adjustments in invoice processing
Creation of CI/CD build processes
Development using Test Driven Development
Team size: 6
Technologies & Tools: Java, Struts, Hibernate, Oracle, BIRT

Jul 2009 - Dec 2009

6 months

Java Developer

Development of PDF reports using iText
Test Driven Development
Architecture planning for extending the application
Internationalization and design of the PDF reports
Team size: 2
Technologies & Tools: Java, DB2, iText

Jul 2007 - Jun 2009

2 years

Java Developer

Development of web crawlers in the credit reporting field, incl. press crawlers
Operation and maintenance of imprint and company monitoring crawlers
Development of a frontend for evaluating results by research staff
Integration of crawler execution in UC4
Team size: 2
Technologies & Tools: Java, DB2, JSF, Lucene, UC4

Nov 2003 - Jun 2007

3 years 8 months

Software Architect

Responsible for development and architecture of a ROLAP engine for analytical database marketing (target group segmentation, response analysis)
Coordination of test management with the client
Support with target group definition within the ROLAP engine
Architecture planning for extending the application
Test Driven Development
Team size: 6
Technologies & Tools: Java, Struts, Hibernate, AspectJ, Oracle

Industry experience

See where this freelancer has spent most of their professional time.

Experienced in Information Technology, Transportation, Construction, Retail, Banking and Finance, and Insurance.

Information Technology

Transportation

Construction

Retail

Banking and Finance

Insurance

Business area experience

See which departments and functions this freelancer has contributed to most.

Experienced in Information Technology, Product Development, Operations, Supply Chain Management, Project Management, and Business Intelligence.

Information Technology

Product Development

Operations

Supply Chain Management

Project Management

Business Intelligence

Skills

Top Skills

Java (22 Years)
Kotlin (7 Years)
Spring Boot (8 Years)
Kubernetes (4 Years)
Azure (6 Years)
Tdd (10 Years)
Jee (10 Years)
Rest (7 Years)
Angular (5 Years)
Spark (2 Years)

Industry Experience

Automotive (12 Years)
Leasing (5 Years)
Insurance (5 Years)
Credit Bureau (2 Years)
E-Commerce (4 Years)
Shipping Logistics (1 Year)

Non-Dev Experience

Tech Lead (2 Years)
Technical Project Management (5 Years)
Product Owner (1 Year)
Data Protection Officer (1 Year)

Programming Languages

Java (=Excellent)
Kotlin (=Excellent)
Typescript (=Excellent)
Scala (=Medium)
Javascript (=Excellent)
Rust (=Basic)
Oracle (=Good)
Sql (=Excellent)
Postgres (=Good)
Mongodb (=Excellent)
Redis (=Medium)
Cosmosdb (=Medium)
Neo4j (=Basic)
Duckdb (=Excellent)

Databases

Oracle – Expert Knowledge
Postgressql – Expert Knowledge
Mysql – Basic Knowledge
Mssql – Advanced Knowledge
Mongodb – Expert Knowledge
Arango Db – Basic Knowledge
Elastic Search – Advanced Knowledge
Neo4j – Advanced Knowledge
Liquidbase – Expert Knowledge
Flyway – Expert Knowledge

Frameworks

Angular – Advanced Knowledge
React – Advanced Knowledge
Spring Boot – Expert Knowledge
Java Ee (Jakarta Ee) – Expert Knowledge
Jax-Ws – Expert Knowledge
Bootstrap – Basic Knowledge
Apache Camel – Basic Knowledge
Apache Wicket – Basic Knowledge
Google Web Toolkit (Bootstrap / Platform / Ext / Rpc) – Advanced Knowledge
Hibernate – Expert Knowledge
Struts – Expert Knowledge
Flutter – Basic Knowledge

Libraries

Rxjs – Basic Knowledge
Material-Ui – Basic Knowledge
Jquery – Basic Knowledge
Spring Data – Expert Knowledge

Interfaces

Rest – Expert Knowledge
Graphql – Expert Knowledge
Grpc – Basic Knowledge
Soap – Expert Knowledge
Openapi/Swagger – Expert Knowledge

Cloud

Aws – Basic Knowledge
Azure – Expert Knowledge
Openshift – Advanced Knowledge
Kubernetes – Expert Knowledge

Testing

Selenium – Basic Knowledge
Jest – Basic Knowledge
Junit – Expert Knowledge
Mockito – Expert Knowledge
Wiremock – Expert Knowledge
Postman – Expert Knowledge
Soapui – Expert Knowledge
Apache Jmeter – Basic Knowledge

Messaging

Apache Kafka – Basic Knowledge
Nats – Expert Knowledge
Activemq – Advanced Knowledge
Redis – Expert Knowledge
Jms – Advanced Knowledge

Operating Systems

Windows – Expert Knowledge
Linux – Advanced Knowledge
Macos – Expert Knowledge

Project Methods

Scrum – Expert Knowledge
Kanban – Expert Knowledge
Waterfall Model – Expert Knowledge
V-Model – Expert Knowledge
Spiral Model – Basic Knowledge

Tools

Git – Expert Knowledge
Gitlab – Advanced Knowledge
Github – Basic Knowledge
Bitbucket – Basic Knowledge
Apache Subversion – Advanced Knowledge
Jira – Expert Knowledge
Confluence – Expert Knowledge
Trello – Expert Knowledge
Sonarqube – Basic Knowledge
Docker – Advanced Knowledge
Jenkins – Advanced Knowledge
Apache Maven – Expert Knowledge
Gradle – Advanced Knowledge
Terraform – Basic Knowledge
Glassfish – Basic Knowledge
Oracle Sql Developer – Expert Knowledge
Jpa – Expert Knowledge
Jsp – Expert Knowledge
Keycloak – Advanced Knowledge

Platforms

Camunda – Expert Knowledge
Cadence – Advanced Knowledge
Apache Kafka – Basic Knowledge

Concepts

Code Review – Expert Knowledge
Pair Programming – Advanced Knowledge
Tdd – Test Driven Development – Expert Knowledge
Clean Code – Expert Knowledge
Solid – Expert Knowledge
Bdd – Behavior-Driven Development – Advanced Knowledge
Responsive Design – Basic Knowledge
Component-Oriented Web Development – Expert Knowledge
Redux – Basic Knowledge

Architecture Pattern

Domain-Driven Design (Ddd) – Advanced Knowledge
Microservices – Expert Knowledge
Mvc (Model-View-Controller) – Expert Knowledge
Mvvm (Model-View-Viewmodel) – Basic Knowledge

Ides

Intellij – Expert Knowledge
Vscode – Advanced Knowledge
Eclipse – Expert Knowledge

Miscellaneous

Spring Eco – Expert Knowledge
Ci/Cd Pipelines – Expert Knowledge
Apache Tomcat – Expert Knowledge
Apache Spark – Expert Knowledge
Orm Modeling With Hibernate – Expert Knowledge
Java Servlet – Expert Knowledge
Websphere Application Server – Basic Knowledge
Extreme Programming (Xp) – Basic Knowledge
Oauth 2.0 / Openid Connect – Advanced Knowledge

Languages

German

Native

English

Advanced

Spanish

Elementary

Education

Dipl.-Business Informatiker · Business Informatics

Statistics

Experience

Total positions 17

Experience in Information Technology 16 y

Avg length 1 y 11 m

Longest experience 8 y 8 m

Expertise

Recent roles Senior Fullstack Developer, Team Lead Data Migration, Senior Backend Developer and Data Engineering

Main industries Information Technology, Transportation, Construction

Main business areas Information Technology, Product Development, Operations

Profile

Member since

April 2025

Last update

August 2026

Need a freelancer? Find your match in seconds.

Try FRATCH GPT

Frequently asked questions

Have questions? Find more information here.

Timo is based in Bremen, Germany and can operate in on-site, hybrid, and remote work models.

Timo speaks the following languages: German (Native), English (Advanced), Spanish (Elementary).

Timo has at least 23 years of experience. During this time, Timo has worked in at least 12 different roles. The average length of individual experience is 1 year and 4 months. Note that Timo may not have shared all experience and actually has more experience.

Based on recent experience, Timo would be well-suited for roles such as: Senior Fullstack Developer, Team Lead Data Migration, Senior Backend Developer and Data Engineering.

Timo's most recent position is Senior Fullstack Developer.

Timo is most experienced in industries like Information Technology, Transportation, and Construction. Timo also has some experience in Retail, Banking and Finance, and Automotive.

Timo is most experienced in business areas like Information Technology, Product Development, and Operations. Timo also has some experience in Supply Chain Management, Project Management, and Business Intelligence.

Timo has recently worked in industries like Construction, Transportation, and Retail.

Timo has recently worked in business areas like Information Technology, Operations, and Supply Chain Management.

Timo attended education in Business Informatics.

Timo will be available full-time from January 2027.

Daily rate distribution

0 2 4 6 8

<€800 €800-1200 €1600+

The rates shown represent the typical market range for freelancers in this position based on recent contracts on our platform.

Average rates for similar positions

Rates are based on recent contracts and do not include FRATCH margin.

1000

750

500

250

Daily rate avg. 968 €

The average daily rate is the mean of all daily rates from recent contracts of comparable freelancers on our platform.

1000

750

500

250

Median rate 880 €

The median daily rate is the middle value of all daily rates — half of comparable freelancers charge less, half charge more. Unlike the average, it is barely affected by outliers.

Calculated based on our freelancers’ daily rates as of 8 Sep 2026. Actual rates may vary depending on seniority level, experience, skill specialization, project complexity, and engagement length.