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Postgres has a feature called logical replication that can synchronize data in real-time. Logical replication is a way of ensuring copies of the database are always in sync. You can use it to build a web application with ASP.NET 5 that can react to all the inserts, updates, and deletes that any user of the app commits to a Postgres database. With this library that I named DotNetify.Postgres (source code), your project won’t involve polling the database, setting up a complicated pub/subsystem.