Local testing via Unity's Multiplayer Play Mode

Multiplayer Play Mode (MMPM) is Unity's official solution for local multiplayer testing, available from Unity 6.

Pros

• Short iteration times

• Tighter integration within the Editor, doesn't require multiple (standalone) Editors open

Cons

• Requires Unity 6+

• Can be more resource demanding than just running builds

How to use?

• Install MPPM as described in their Installation Instructions

• Open Window > Multiplayer Play Mode

• Enable up to 4 virtual Players

• Make sure that the baked data is up-to-date before starting to test, and that the Replication Server is running with the latest schema

• Enter Play Mode

coherence tells apart virtual Players from the main Editor, so it's easier for you to not edit assets in clones by mistake.