Seven-layer banking architecture by responsibility

The decision

Distribute responsibilities across seven layers, each with explicit ownership and its own cadence of change, so the channel can evolve without dragging the core with it.

Why it mattered

Mixing channel, business, integration, and core logic would carry coupling into the target state and make ownership, testing, and evolution harder.

The trade-off

More layers increase contracts and integration discipline, but reduce responsibility coupling and allow channel, domain, integration, and core to evolve with less interference.

What changed

Separation of responsibilities became the structural basis for domains, APIs/services, integration, and multidisciplinary teams.

The outcome

The architecture and application platform reached production.

Summary of a documented architecture decision. Method, mechanism and supporting evidence are not published.