Compatibility matrix

The framework’s features have different support levels across runtimes. This page is the definitive reference.

For each row:

✓ = supported, tested in CI.
⚠ = works, but not actively CI’d.
✗ = not supported.
N/A = doesn’t apply.

Core

Feature	Bun	Node 20+	Deno
`Actor` base class	✓	✓	✓
`ActorSystem`	✓	✓	✓
`Props` + `withDispatcher` etc.	✓	✓	✓
`MicrotaskDispatcher` / `ImmediateDispatcher` / `ThroughputDispatcher`	✓	✓	✓
`BoundedMailbox` / `PriorityMailbox`	✓	✓	✓
Supervision strategies	✓	✓	✓
`context.timers` + `system.scheduler`	✓	✓	✓
Death watch	✓	✓	✓
`become` / `stash` / `unstashAll`	✓	✓	✓
Pattern matching (ts-pattern)	✓	✓	✓

Typed API

Feature	Bun	Node 20+	Deno
`Behaviors.*` combinators	✓	✓	✓
`TypedActor`	✓	✓	✓
`spawnTyped` / `spawnTypedChild` / `typedProps`	✓	✓	✓

Routing + patterns

Feature	Bun	Node 20+	Deno
`Router.*`	✓	✓	✓
`CircuitBreaker`	✓	✓	✓
`BackoffSupervisor`	✓	✓	✓
`retry`, `pipeTo`, `after`	✓	✓	✓

Cluster

Feature	Bun	Node 20+	Deno
Cluster join / membership	✓	✓	⚠
Gossip + failure detector	✓	✓	⚠
`TcpTransport`	✓	✓	⚠
TLS on cluster transport	✓	✓	⚠
`InMemoryTransport` (tests)	✓	✓	✓
`ClusterSingleton`	✓	✓	⚠
`ClusterSharding`	✓	✓	⚠
`DistributedPubSub`	✓	✓	⚠
`DistributedData`	✓	✓	⚠
Cluster router	✓	✓	⚠
Receptionist	✓	✓	⚠
`KubernetesLease`	✓	✓	⚠
`InMemoryLease`	✓	✓	✓

Persistence

Feature	Bun	Node 20+	Deno
`InMemoryJournal`	✓	✓	✓
`InMemorySnapshotStore`	✓	✓	✓
`SqliteJournal`	✓ (`bun:sqlite`)	✓ (`better-sqlite3` peer dep)	✗
`SqliteSnapshotStore`	✓	✓	✗
`CassandraJournal`	⚠	✓ (`cassandra-driver`)	⚠
`CachedSnapshotStore`	✓	✓	✓
`PersistentActor`	✓	✓	✓
`DurableStateActor`	✓	✓	✓
`ProjectionActor`	✓	✓	✓
Object-storage snapshot store (filesystem)	✓	✓	✓
Object-storage snapshot store (S3)	⚠	✓	⚠
Schema-migration adapters	✓	✓	✓
Replicated event sourcing	⚠	✓	✗

I/O brokers

Feature	Bun	Node 20+	Deno
`KafkaActor` (`kafkajs`)	✓	✓	⚠
`MqttActor` (`mqtt`)	✓	✓	⚠
`AmqpActor` (`amqplib`)	⚠	✓	⚠
`NatsActor` (`nats`)	✓	✓	⚠
`JetStreamActor`	✓	✓	⚠
`RedisStreamsActor` (`redis`)	✓	✓	⚠
`GrpcServerActor` / `GrpcClientActor`	✓	✓	⚠
`WebSocketActor` (client)	✓	✓	✓
`ServerWebSocketActor`	✓ (`Bun.serve`)	✓ (`ws`)	⚠
`SseActor`	✓	✓	✓
`TcpSocketActor`	✓	✓	✓
`UdpSocketActor`	✓	✓	✓

HTTP

Feature	Bun	Node 20+	Deno
Route DSL	✓	✓	✓
Marshalling (`entity<T>`)	✓	✓	✓
`FastifyBackend`	✓	✓	✓
`BunServeBackend`	✓	N/A	N/A
`ExpressBackend`	✓	✓	⚠
Middleware (response-cache, rate-limit, idempotency-key)	✓	✓	✓
`HttpClient` (uses fetch)	✓	✓	✓
`HttpManagement`	✓	✓	✓

Cache

Feature	Bun	Node 20+	Deno
In-memory cache	✓	✓	✓
Memcached cache	⚠	✓	⚠
Redis cache	✓	✓	⚠

Serialization

Feature	Bun	Node 20+	Deno
JSON	✓	✓	✓
CBOR	✓	✓	✓
Custom serializers	✓	✓	✓

Observability

Feature	Bun	Node 20+	Deno
Core metrics	✓	✓	✓
Prometheus exporter	✓	✓	✓
`prom-client` adapter	✓	✓	⚠
OTel metrics adapter	✓	✓	⚠
`RecordingTracer`	✓	✓	✓
OTel tracing adapter	✓	✓	⚠
Stock metrics	✓	✓	✓
Health checks	✓	✓	✓

TestKit

Feature	Bun	Node 20+	Deno
`TestKit.create`	✓	✓	✓
`TestProbe`	✓	✓	✓
`ManualScheduler`	✓	✓	✓
`MultiNodeSpec`	✓	✓	⚠
`ParallelMultiNodeSpec`	✓	✓	⚠

Cell-recommended targets

For new projects:                              Bun
For Node-shop environments:                    Node 20+
For Lambda / serverless:                       Node 20+
For Deno-first organizations:                  Deno (with caveats)
For mixed:                                     Pick one per cluster

⚠ = the framework hasn't seen production hours on this runtime
for this feature.  Usually works; might have edge cases.

If you encounter problems on a ⚠ feature, file a bug — most Deno-specific issues are simple fixes.

Where to next

Runtime overview — the conceptual model.
Bun / Node / Deno — per-runtime details.
Installation — install steps.