Freelancer profile translated to English.
Back to original languageAbout Frank
Graduate mathematician with many years of experience in software development. Specialized in the conception, implementation, and modernization of data-driven systems in the enterprise environment. Technical focus on Java-based backend systems, asynchronous processing, and integrations into existing IT landscapes. Frontend experience in Angular / TypeScript completes the profile.
German
Native or bilingual
English
Conversational
Can work on-site
Düsseldorf (up to 50km), Dresden (up to 30km)
Experience
- Unternehmen aus der FinanzdienstleistungsbrancheFull-Stack Developer / Software ArchitectBANKING AND INSURANCEJuly 2024 - March 2025 (8 months)Düsseldorf, GermanyProject Goals:
- Development of a scalable, REST-based matching service for automated assignment of semi-structured company addresses against an internal database
- Implementation of a web-based user interface for monitoring and controlling the service, including asynchronous processing of large data sets
- Deployment in a containerized architecture on Kubernetes
Tasks and Responsibilities:- Functional requirements analysis and conception of the matching service
- Development and optimization of search schemas for international addresses in Apache Solr using tokenizers, normalizers, stemming and phonetic algorithms, as well as nested documents to map address changes
- Implementation of an automated import service for large data sets delivered via SFTP, including synchronization between database and Solr index
- Development of a REST-based matching service, including import and search interfaces
- Development of an innovative text analysis component based on an extended aho-corasick variant for recognizing typical address components
- Realization of an asynchronous matching service with REST API for processing and returning Excel and CSV matching requests
- Development of algorithms for removing encoding artifacts (Mojibake) and GDPR-compliant deletion processes in the database and Solr
- Creation of an Angular-based user interface for process monitoring and data transfer
- Connection to LDAP/Active Directory with role-based access control
- Implementation of extensive unit tests as well as performance and load tests
- Setup of an automated CI/CD process with Jenkins and Helm for build, release, and deployment
- Coordination with the deployment team regarding cluster resources and connection to Active Directory Services
- Go-live and support of the solution in ongoing operation
- Unternehmen aus der FinanzdienstleistungsbrancheFull-Stack DeveloperBANKING AND INSURANCEApril 2024 - July 2024 (3 months)Düsseldorf, GermanyProject Goals:
- Further development of a database-driven, asynchronously processing billing service with the aim of improving the connection to the Business Intelligence system Cognos
- Implementation of new functional requirements in the area of price calculation
Tasks and Responsibilities:- Creation and integration of a dashboard for monitoring the billing process (readiness to start, status display, error diagnosis) into the web interface
- Error analysis and correction for file import via SFTP
- Improvement of synchronization between multiple web clients
- Implementation of export functions for backing up job chain definitions and the complete parameterization of the billing process (as zipped JSON files for backup creation and system migration)
- Optimization of error handling in the backend and frontend to improve user-friendliness
- Correction of synchronization problems with JMS-based data exchange
- Conception and implementation of a new pricing logic in the billing process:
- Implementation of individual pricing rules for specific customers within the new pricing logic
- Export of pricing components to an connected SAP system
- Close coordination with business analysts for functional specification and validation of the logic
- Implementation of a batch job for transferring billing data to the BI system Cognos
- Regular coordination with the deployment team and responsibility for the go-live of the solution
- Unternehmen aus der FinanzdienstleistungsbrancheFull-Stack DeveloperBANKING AND INSURANCEJanuary 2024 - April 2024 (3 months)Düsseldorf, GermanyProject Goals:
- Comprehensive technical modernization of an established database-driven batch service, including REST interfaces
- Update to current versions of central frameworks and cleanup of the architecture
- Improvement of modularization
- Increase in code quality, stability, and security
Tasks and Responsibilities:- Technology Upgrades:- Java 11 → Java 21
- Spring Framework 4.3 → 6.1, Spring Boot 1.5 → 3.2
- Spring Batch 4.3 → 5.1, Hibernate 5.3 → 6.4
- Quarkus 2 → 3 (REST service), Angular 15 → 17 (Frontend)
- Switch from Tomcat → Undertow
- Migration from javax to Jakarta EE 10 throughout the code (incl. REST and Batch)
- Database Migration & Schema Adjustments:- Update of database schemas for Spring Batch and job chain control as part of the framework upgrade
- Creation of SQL scripts for data migration between old and new database schemas
- Architecture & Refactoring:- Separation of the codebase into business logic and control components
- Modularization by outsourcing batch job and job chain logic
- Conversion of batch job configuration from XML to Java Beans
- Removal of outdated dependencies and legacy code
- Self-implementation as a replacement for the incompatible spring-batch-admin-manager
- Implementation of an algorithm for compatibility of ExecutionContext between old and new Spring Batch versions
- Code Quality & Testing:- Execution of comprehensive functional tests and expansion of test coverage using unit tests
- Improvement of file imports and error handling
- Logging & Security:- Fix of security-related vulnerabilities
- Expansion of logging (e.g., user actions in DB)
- Error correction in logging via syslog and console (LogHandler)
- Other:- Implementation of a new batch job for data import via an external REST API
- Close coordination with the deployment team and support for the go-live
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Education
- Diploma MathematicsUniversity of Wuppertal2013Komplexe Analysis, Geometrie, Numerik, Wissenschaftliches Rechnen