Founder of RudderStack here (we are an open-source Segment alternative)
Segment (or RudderStack) is primarily for routing event-data from your apps to multiple destinations (cloud SaaS, warehouse etc). On the other hand, AppFlow is for syncing data that lives on cloud applications with AWS products like RDS, RedShift etc. So, both the nature of data is very different (event-streams vs database update batches) and also the destinations where they are sent (multiple cloud applications + data-warehouse VS only datawarehouses/databases).
Segment also has a product similar to AppFlow called Segment Sources but that's not what Segment is known for. There are a bunch of other products in that space like Blendo & FiveTran.
Segment (or RudderStack) is primarily for routing event-data from your apps to multiple destinations (cloud SaaS, warehouse etc). On the other hand, AppFlow is for syncing data that lives on cloud applications with AWS products like RDS, RedShift etc. So, both the nature of data is very different (event-streams vs database update batches) and also the destinations where they are sent (multiple cloud applications + data-warehouse VS only datawarehouses/databases).
Segment also has a product similar to AppFlow called Segment Sources but that's not what Segment is known for. There are a bunch of other products in that space like Blendo & FiveTran.