API Changes (v4.0.0) - GoAkt

A quick summary of v4.0.0 changes. For the complete migration guide, see Migration from v3.x.

Executive summary

v4.0.0 delivers simplification and performance:

Theme	Key changes
Unified APIs	Single actor reference (`*PID`), single lookup (`ActorOf`), unified scheduler
Type flexibility	`any` replaces `proto.Message`; CBOR for arbitrary Go types
Remoting	Config-only public API; client is internal
Identity	`Path` interface replaces `*address.Address`
Performance	Low-GC serialization, lock-free type registry, single-allocation frames

Quick migration reference

From	To
`proto.Message` in handlers	`any`
`goaktpb.*` types	`actor.*` (e.g., `actor.PostStart`, `actor.PoisonPill`)
`ActorRef`	`*PID`
`ActorOf` → `(addr, pid, err)`	`ActorOf` → `(*PID, error)`
`LocalActor(name)`	`ActorOf(ctx, name)`
`RemoteActor(ctx, name)`	`ActorOf(ctx, name)`
`pid.Address()`	`pid.Path()`
`ctx.SenderAddress()`	`ctx.Sender().Path()`
`WithRemoting`	`WithRemote(config)`
`address` package	`internal/address`; use `Path` interface

New additions

Pluggable serializers — ProtoSerializer (default), CBORSerializer for any Go type
Path interface — Location-transparent actor identity
Extended Logger — Context-aware logging, Enabled, With, Flush, etc.
Slog and Zap implementations — Low-GC logging options

Interfaces Reference Glossary