Case study

Card-Linked Rewards Platform

A real-time rewards engine that links card transactions to brand campaigns, with exactly-once attribution and a ledger that reconciles to the cent.

Client type
Consumer fintech launching a rewards product (sample scenario)
Industry
FinTech
Duration
10 months

Sample contentSample engagement. Illustrative scenario used while the site is in build — not a named client project.

fintech2026

Card-Linked Rewards Platform

  • Java
  • Spring Boot
  • Kotlin
  • PostgreSQL

Rewards had to be attributed from raw card transaction feeds, where merchant descriptors are inconsistent, transactions arrive more than once, and a false attribution costs real money. Payouts also had to survive audit.

An event-driven pipeline with a merchant resolution stage, a rules-based attribution engine, and idempotent ledger writes — so a replayed or duplicated transaction can never produce a second reward.

The commercial team could launch and adjust campaigns without engineering lead time, and finance gained a reconciliation trail that stands up to audit.

  1. 01Descriptor analysis across historical transaction data before designing the resolver
  2. 02Dual ingestion — aggregator OAuth connections plus direct network feeds
  3. 03Attribution rules expressed as data, so campaigns change without a deployment
  4. 04Idempotency keys applied at the business boundary, not the transport layer
  5. 05Reconciliation job comparing ledger totals against source feeds continuously

Descriptors are the hard part

“Merchant name” in a card feed is not a merchant name. It is an abbreviation produced by an acquirer, sometimes with a store number, sometimes truncated. Resolving those to brands correctly — and knowing when not to guess — determined whether the rest of the system was trustworthy.

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