Nexus

A typed actor system for PHP 8.5+   WIP

Type-safe actors, supervision trees, event sourcing, multi-process clustering.
Erlang/OTP and Akka patterns — in the PHP you already know.

Documentation · Quick Start · GitHub

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// Define messages
readonly class Ping {
    public function __construct(public ActorRef $replyTo) {}
}
readonly class Pong {}

// Define actor behavior
$pongActor = Behavior::receive(
    static fn(ActorContext $ctx, Ping $msg) => $msg->replyTo->tell(new Pong()) ?? Behavior::same(),
);

// Spawn and interact
$system = ActorSystem::create('my-app', new FiberRuntime());
$ref = $system->spawn(Props::fromBehavior($pongActor), 'pong');
$response = $ref->ask(fn(ActorRef $replyTo) => new Ping($replyTo), Duration::seconds(5));
// $response is Pong

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Key Features

• Type-safe actors — Generic ActorRef<T>, Behavior<T>, Props<T> with Psalm level 1 enforcement
• Supervision trees — One-for-one, all-for-one, exponential backoff with custom exception deciders
• Event sourcing & durable state — Persist events or state snapshots with automatic crash recovery
• Pluggable runtimes — Write once, run on PHP Fibers (dev) or Swoole coroutines (production)
• Multi-process clustering — Consistent hash ring, location-transparent RemoteActorRef, Unix socket transport
• Custom Psalm plugin — 7 actor-specific static analysis rules catch concurrency bugs at compile time

Packages

Package	Description
nexus	Monorepo & meta-package
core	Actors, behaviors, supervision, mailboxes
runtime-fiber	PHP Fiber runtime
runtime-swoole	Swoole coroutine runtime
runtime-step	Deterministic test runtime
app	Application bootstrap with PSR-11
serialization	Message serialization
persistence	Event sourcing & durable state
persistence-dbal	DBAL persistence store
persistence-doctrine	Doctrine persistence store
cluster	Multi-process clustering
cluster-swoole	Swoole cluster transport
psalm	Actor-specific Psalm plugin

Get Started

composer require nexus-actors/nexus

NexusApp::create('my-app')
    ->actor('greeter', Props::fromBehavior($greeterBehavior))
    ->onStart(function (ActorSystem $system) {
        $system->spawn(Props::fromBehavior($greeterBehavior), 'greeter')
            ->tell(new Greet('world'));
    })
    ->run(new FiberRuntime());

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Backed by Monadial · MIT License