Flows can now contain other flows! With nested flows, you can build reusable hierarchies into your tests, inserting a flow inside another flow, with flow parameters passed down through each layer. When you update a nested flow, the change propagates to every parent flow that uses it, reducing duplication and maintenance across your test suite.
Nested flows unlock test patterns that weren’t previously possible in mabl, including:
- Layered flow composition: extract common step sequences into small foundational flows and nest them inside larger feature-specific flows. When the underlying workflow changes, update the one foundational flow instead of editing every test that duplicates those steps.
- Data grid testing: create a flow that loops through rows in a table, then nest a second flow inside it that loops through columns or dropdowns within each row. Complex table-parsing and data-generation scenarios that previously required JavaScript snippets can now be built directly in the Trainer.
- Authentication chains: build layered authentication flows where an MFA flow is nested inside a login flow, which is nested inside a session-setup flow. Each layer is independently maintainable and reusable.
- Conditional logic with repetition: combine conditional steps with nested flows to create branching workflows that repeat across different test contexts without duplicating the branch logic.
Early access
Nested reusable flows are available in early access through Labs. To enable the feature, a workspace owner can toggle it on under Settings > Labs in the mabl web app.
Nested flows are supported in browser and mobile tests.
A nested flow in the mabl Trainer
Try it out
- Ensure a workspace owner has enabled nested reusable flows in Settings > Labs.
- Open a test in the mabl Trainer and import a flow as you normally would.
- Open that imported flow and import another flow inside it. The nested flow appears as a collapsible section within the parent flow.
- To pass data between levels, use flow parameters. Parameters defined on the inner flow can be set from the outer flow, just like when importing a flow into a test.
Nesting depth and safety limits
- Depth: Steps can be nested up to 4 levels deep. This limit is shared between flows and step groups. For example, a flow inside a step group inside another flow all counts toward the same limit.
- Safety limits: To avoid creating infinite loops, mabl automatically detects and prevents circular references. For example, you cannot nest Flow A inside Flow B inside Flow A.
Share feedback
We’d love to hear how nested flows work for your team. Share feedback directly through your CSM or add it in the mabl Product Portal.