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

Reading the warning marker

⚠ = 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.

Version pinning

package.json

{ "engines": { "bun": ">=1.1.30", "node": ">=22.12" } }

Pin both Bun and Node engines if your code runs on either — prevents accidental dev/prod runtime drift.

Where to next

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