Testing flows has long lagged behind Apex testing. Winter '27 introduces a dedicated Test mode in Flow Builder, in beta.
Where
Flow Builder, after enabling the feature in Process Automation Settings. The builder then splits into Build mode and Test mode.
How
Build mode stays focused on configuration while Test mode handles debugging and verification. You create reusable test scenarios per flow path with isolated test data, define mock outputs for external calls, and add assertions on expected results. Test runs report code coverage for your flows.
Why
Flows run business-critical logic but rarely get systematic tests. Bringing scenarios, mocks, assertions, and coverage into the builder moves flow development closer to real software engineering practice. As a beta, expect each flow path to need its own manually created scenario.