Challenge
A leading German bank wanted to offer card-linked cashback rewards to increase card usage and customer retention. When customers made purchases at participating merchants using their bank card, they would receive cashback directly into their bank account. The bank needed the full stack - a customer-facing portal, an internal management system for non-technical teams, and backend infrastructure that integrated with their existing banking APIs and merchant affiliate networks.
Approach
We designed and built the entire platform across four layers:
- Customer portal (React) - a user-facing web application where cardholders browse participating merchants by location, track purchases, and monitor cashback earnings. Location-based merchant discovery with filtering by category, distance, and cashback percentage
- Internal CMS - a content management system built for the bank’s non-technical marketing and partnerships team. They manage merchant listings, configure cashback rates per location, control featured promotions, and publish content to the customer portal - all without developer involvement
- Microservices backend - two separate backend services: one powering the CMS and customer portal, and a second handling affiliate and partnership aggregation with external merchant networks
- Search and indexing pipeline - Elasticsearch with Logstash ingesting and indexing data from the bank’s internal APIs, enabling fast merchant search, location-based queries, and real-time cashback tracking across the portal
Result
The platform went live serving the bank’s cardholders with real-time cashback tracking and merchant discovery. The internal CMS gave the bank’s partnerships team full autonomy to onboard and manage merchants without engineering support, significantly reducing the time to launch new merchant offers. The microservices architecture allowed independent scaling of the customer-facing portal and the affiliate integration layer, and the Elasticsearch pipeline ensured sub-second search performance across the merchant catalog.