Introduction to Failed Events in a Pipeline

Whenever Hevo finds that in an event cannot proceed ahead in the Pipeline it is marked as Failed and made visible on the Hevo UI for inspection.

There can be several reasons for us to mark events as Failed:

  • Network failures. We might encounter network or connectivity failures with your destination at times. We might also encounter network problems in Hevo’s infrastructure. Though we make the best efforts to eliminate all such errors they are still bound to appear once in a while.
  • Schema incompatibility and conflicts. Schema changes in your Sources and Destinations may change without us knowing about those changes. Though we make the best efforts to keep ourselves in sync with all those changes, there can always be a certain lag in doing so.
  • Bad transformation code. Transformation code provided by you may have bugs.
  • Incorrect mappings. There can be manual errors while mapping source and destination tables.

All such failed events visible on the Pipeline’s Overview screen for inspection.

Replaying events

A majority of the failed events are replayed by Hevo as and when it finds that the underlying reason for those events to fail has been resolved. In some cases, however, you may have to confirm that you have taken the suggested action. Hevo will then try to Replay the events and if they fail again, you will find them again as Failed in a couple of minutes.

When replayed, events are fed back into the Transformations stage of the pipeline.

Note: In case the events were created through the Transformations Code they are fed back to the Schema Mapper stage rather than Transformations stage.

View Sample events

You may want to view a few sample events which were marked as Failed to get to the root cause. You can view Sample events by clicking the View Sample link.


The failed events are held by Hevo for 30 days, after which they will be purged permanently. Purged events will not be replicated to your Destination. Hence, you have to resolve all of the failed events within 30 days.