Projects with the use of API-First

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API-First

Period: 03/2020 – 06/2023
Role: Software Developer
Client: Lowell
Team size: 3
Person days: 120

Lowell follows an API-First strategy. The goal was to make the API available to external processes as well. To this end, a central API was provided fully automatically and used by all services. The API is subject to strict guidelines regarding design and backwards and/or forwards compatibility depending on the use case.

My contributions to the project::
  • Concept and creation of a central API-First repository based on Protobuf
  • Automated generation of release and pre-release versions for multiple programming languages to optimize development speed
  • Concept for API versioning
  • Creating APIs
  • Documentation of the API
  • Reviewing APIs with a primary focus on clarity, documentation, and breaking changes

Claim Data for the Consumer Portal

Period: 01/2020 – 06/2023
Role: Software Developer
Client: Lowell
Team size: 4
Person days: 50

Lowell's consumer portal is a central digital service platform for individuals with outstanding claims at the debt collection agency. Lowell consists of multiple companies that are separated both organizationally and technically. Several different debt collection software systems had to be mapped onto a single API.

My contributions to the project::
  • Onboarding new Lowell subsidiaries
  • Adaptations and extensions of the interfaces
  • Definition of the API with a focus on compatibility
  • Testing the interface locally, in the CI build, and in production (partially semi-automated)
  • Rolling out the API with zero downtime in a Kubernetes cluster
  • Analysis and resolution of production errors
  • Reduction of the number of services, as the microservices had been cut too small
  • Fixing security vulnerabilities and hardening API interfaces after penetration tests
  • Guiding the development team to sustainably avoid identified weaknesses
  • Defending the system architecture against external security auditors