ElectricSQL replication uses the Satellite protocol over a web socket connection.
This protocol is agnostic to the client and is designed to be used from multiple languages as a standard integration point.
See the protocol definition at electric-sql/electric/protocol.
The Electric server implementation is at electric-sql/electric/components/electric/lib/electric/satellite.
The Typescript client implementation is at electric-sql/electric/clients/typescript/src/satellite.