Software ArchitectureAtlas

Software Architecture Atlas

Gain an overview. Understand the connections.

Guiding scenario · Order B-1042

Order B-1042 end to end

You follow order B-1042 through seven steps across the shop and to its partners, from cart to shipping. Turn on a fault and see which building block protects the flow.

The flow in the shop

  1. Basket2 × mug at €24.95 each

    Convert cart into order

    running: The cart hands the items over to the order module. The price is locked in at this point.

    Module boundariesAPI contracts

  2. OrderB-1042 · created

    Create and save order

    running: The order is saved in the shared database and receives its identifier B-1042.

    Transaction boundariesModular monolith

  3. InventoryB-1042 · reservation R-77

    Stock Reserve

    running: Inventory holds two mugs for B-1042 and returns reservation R-77.

    Transaction boundariesData ownership

  4. Payment → payment providerP-731 · €49.90 · pay-B-1042

    Authorise payment with the provider

    running: The payment module queries the provider with a fixed key and a time budget of 1 s.

    TimeoutIdempotencyRetry

  5. OrderB-1042 · confirmed

    Confirm order

    running: With the payment confirmed, the order module sets the status to confirmed. The customer sees the acceptance.

    Transaction boundariesPartial failures

  6. Invoice (worker via broker)R-882 · open · B-1042

    Create invoice via the broker

    running: The confirmation is staged in the same transaction and passed via the broker to the invoice worker.

    Transactional OutboxDelivery guaranteesIdempotency

  7. Shipping → shipping carrierB-1042 · shipping notification

    Commission shipping and accept notification

    running: The shipping carrier receives the job. Its notification belongs to exactly one order and is checked.

    Trust BoundariesAuthentication & authorisation

The building blocks behind it

Principles · ConceptModule boundariesModule boundaries define which data and capabilities a module owns and which contracts others use to access them.Communication · ConceptAPI contractsAPI contracts define data, meaning and observable interface behavior as binding rules.Data · ConceptTransaction boundariesTransaction boundaries determine which related changes succeed or fail together.Styles & patterns · StyleModular monolithA modular monolith separates domains within a single application deployed as one unit.Data · ConceptData ownershipData ownership defines which building block is responsible for data and its domain rules.Operations · MechanismTimeoutA timeout limits waiting time. Here you learn how the caller handles the resulting state.Communication · ConceptIdempotencyIdempotence keeps the business effect stable when the same command is repeated.Operations · MechanismRetryRetry repeats a failed operation within defined limits and conditions.Distribution · Failure modePartial failuresHere you learn how to handle failed participants and uncertain outcomes in distributed workflows.Communication · PatternTransactional OutboxTransactional Outbox stores a domain change together with the intent to publish it.Distribution · ConceptDelivery guaranteesDelivery guarantees describe when messages are lost, redelivered or processed.Security · ConceptTrust BoundariesTrust Boundaries mark transitions between trust levels that require protection and validation.Security · ConceptAuthentication & authorisationAuthentication establishes identity; authorization checks whether an action is permitted.