Crossactor

Crossactor is a term used to describe actors that communicate across process, language, or network boundaries within an actor-based or message-driven system. It is not a formal standard with a single specification, but a recurring concept in discussions of distributed concurrency and modular architectures.

At its core, cross-actor communication extends the basic actor model by enabling actors in different runtimes, machines, or domains to exchange messages and participate in shared workflows. Implementations typically employ adapters or bridges that translate between internal message formats and the chosen transport protocol, and rely on serialization schemes, stable interfaces, and versioning to maintain compatibility. Common transport options include message brokers, HTTP or gRPC, or custom TCP/RPC channels.

Key properties include asynchrony, message-driven flow, fault isolation, and fault tolerance. Cross-actor systems may implement supervision strategies and backpressure to manage load. Location transparency means a sender need not know the precise location of a recipient. However, cross-boundary communication increases latency and introduces ordering and consistency challenges, and it raises security and governance concerns.

Use cases include distributed workflows and microservice architectures that use the actor model, cross-language actor ensembles, edge-to-cloud processing, and streaming pipelines where processing nodes are dynamically scaled in different runtimes.

Design considerations involve contract stability, versioning of interfaces, message idempotency, delivery guarantees, and observability across boundaries. While cross-actor design can improve modularity and scalability, it requires careful handling of latency, failure modes, and security.