The 4th and the last architectural principle in Canton is Atomic Transactions.

Atomic transactions are often described through the “all or nothing” principle, where a transaction either completes fully or does not complete at all, but in a distributed financial workflow this becomes much more complex because several independent parties, assets and systems need to move together without one central authority controlling the whole process.

Trade settlement is rarely a single movement and often involves cash, securities, custodians, registrars, and settlement platforms that must remain synchronized so one side does not complete while the other fails or remains uncertain.

In Canton Network, atomic transactions are applied to distributed workflows, where Daml structures can check whether each participant has the required assets and permissions before the transaction is processed. If all required conditions are satisfied, the linked movements can complete together. If they are not satisfied, the workflow is not completed.

Such an approach can support simultaneous settlement of cash and securities, clearer committed settlement status, reduced clearing dependency in some market designs, real-time ownership records and interoperability with other ledgers such as KYC or eligibility applications.