OpenBank
Explore the sandbox ↗
Money, identity & time
Money types with rounding policy, IBAN and Czech account checks, identity numbers and a banking calendar that handles working days and Easter.
Explore libs-domain ↗OpenBank Labs 
/ Shared banking intelligence
A shared kernel
for modern banks.
Every bank needs to count money, understand business days and speak payment rails. Those rules should be written once, tested deeply and shared.
From common logic to extraordinary banks.
Build on what matters.Inside openbank-libs
The banking knowledge
services share.
The domain core is plain Kotlin without framework dependencies. Shared types and rules help services agree at the source instead of reconciling differences later.
Loans that add up
Amortization, APRC, IFRS 9 and delinquency calculations are shared building blocks rather than slightly different implementations in every service.
Explore libs-lending ↗ISO 20022
Reusable messages for pacs.008, pacs.002, pacs.004 and camt.054/056 make payment flows speak the same language.
Explore libs-iso20022 ↗Rules around the work
Transactional outbox, idempotency, audit and authorization primitives reduce the need to rebuild the same infrastructure service by service.
Explore libs-runtime ↗Durable workflows
Shared temporal patterns help long-running banking work remain explicit and recoverable.
Explore libs-temporal ↗Test the promises
Testcontainers, money generators for property tests and conformance checks help prove outbox and authorization behavior.
Explore libs-testing ↗Open source · open questions
No one should write APRC
for the hundred and first time.
The ambition is a reusable bank kernel: shared foundations that leave teams free to build their own customer experience.