Compatibility

synkd aims to keep PartyKit-shaped party code portable. Some platform features differ between Node and a Durable Objects host.

Runtime matrix

Capability	Node (synkd up)	Durable Objects (synkd up --durable / deploy)
/parties/:party/:room	Yes	Yes
onConnect / onMessage / broadcast	Yes	Yes
Connection tags	Userland on Connection	Native getTags when the host supports it
Hibernatable WebSockets	Idle empty rooms unload	Platform acceptWebSocket
Close 1012 on move or reload	Yes	Yes (ownership move)
Per-room storage	SQLite files	Durable Object storage
Alarms	Polled scheduler	DO alarm()
Yjs	@synkd/y	Same party, wrapped for DO
request.cf geo	Not available	Not available
Workers AI / Vectorize	Not a goal	Not a goal
partysocket clients	Yes	Yes

Platform notes

• Prefer Node for everyday local work. Use Podman or Docker for synkd up --durable and production fleets.
• One Durable Objects fleet is one trust domain. Do not co-host hostile tenants on the same fleet. See Security.

Probe live capabilities

synkd up --durable

Then:

curl -s "http://127.0.0.1:9876/parties/main/healthz?token=dev-token&synkd_caps=1"

Setup guide: Deploy.

Look for acceptWebSocket, getWebSockets, and getTags in the response.

Known gaps versus PartyKit cloud

1. No *.partykit.dev hosted control plane or preview hosts.
2. No Workers AI or Vectorize bindings.
3. Node storage values are JSON-serialised, not a full structured clone.
4. Multi-tenant SaaS needs separate fleets, not soft tenancy inside one fleet.

What to do next

• Deploy with TLS when you are ready for a fleet
• Deploy for local Durable Objects and fleet setup