Issue
Does Heroku Postgres support logical replication?
Resolution
We don't support logical replication from external instances for Heroku Postgres instances.
However, if you are using Apache Kafka on Heroku on a Private Space you can get logical replication-like behavior, by using Heroku Streaming Data Connectors. This allows the streaming of data from Heroku Postgres to Heroku Kafka. External connectors can still be setup to read from the Kafka instance.
Comments or votes for this feature can be added to this Heroku Public Roadmap issue: https://github.com/heroku/roadmap/issues/38