Compensation Boundary Event
Attaches a compensation handler to an activity: if compensation is later triggered, the linked handler undoes this activity's completed work. Double circle with rewind arrows.
The Compensation Boundary Event is unlike other boundaries: it does not react while the activity runs — it registers the undo recipe for after the activity has completed. The dotted association links it to a dedicated compensation activity (marked with the rewind icon) that performs the undo when a Compensation Throw/End fires.
When to use and avoid
When to use
On every activity whose effects may need business undo later (bookings, charges, postings).
In sagas and transactions, to declare each step's inverse operation.
When the undo differs per activity — each gets its own handler.
When NOT to use
For handling failures during the activity — that is an Error Boundary.
When the work has no meaningful inverse — compensation can't manufacture one.
On activities that never complete before the potential rollback point — nothing to undo.
Business example
Declaring how to undo a hotel booking
Open this example in the HEFLO process editor and explore the diagram from the inside.
Open in the HEFLO editor →Step by step
- Book hotel completes normally; its Compensation Boundary (highlighted) + associated handler Cancel hotel booking declare the undo.
- Later, payment is declined and compensation is thrown.
- The engine invokes the handler — the booking is cancelled even though the task had finished long before.
Differences
Compensation Boundary vs other boundaries
Other boundaries watch a running activity. The compensation boundary is dormant during execution and only matters after completion, when compensation is triggered. It also uses an association (dotted) to its handler, not a sequence flow.
FAQ
What marks the handler activity?
It is set as isForCompensation and rendered with the rewind marker; it can't be reached by normal sequence flow — only by compensation.
Does the handler see the original activity's data?
Yes — engines give it the completed activity's context so it can undo precisely (e.g. the booking id).