PgDog is a connection pooler, load balancer and database sharder for
PostgreSQL. Written in Rust, PgDog is fast, reliable and scales Postgres
databases without requiring changes to your application.

It's a single binary, deployed between your application and the database, that
speaks both the protocol applications use to talk to Postgres and the
replication protocol Postgres uses internally. This lets PgDog do its job
transparently, without changes to Postgres or the applications that query it.