Durable Objects

Durable Objects are optional on cellp. celld can run SQLite-backed classes from wrangler, but support is partial compared to Cloudflare. cellp does not branch DO state from a parent version like D1/KV/R2/Queue—each ready version has its own celld fleet and storage.

Treat DO as experimental until you have read the runtime notes below.

Bindings · Binding guides · Wrangler: Configure bindings

1. Declare it

"durable_objects": {
  "bindings": [{ "name": "COUNTER", "class_name": "Counter" }]
},
"migrations": [{ "tag": "v1", "new_sqlite_classes": ["Counter"] }]

Export the class from the same module as your Worker (class_name must match). Example in the repo: dev/examples/counter.

2. Use it in the Worker

export class Counter {
  constructor(state, env) {
    this.state = state
  }
  async fetch(request) {
    const n = (await this.state.storage.get('n')) ?? 0
    await this.state.storage.put('n', n + 1)
    return new Response(String(n + 1))
  }
}

export default {
  async fetch(request, env) {
    const id = env.COUNTER.idFromName('global')
    const stub = env.COUNTER.get(id)
    return stub.fetch(request)
  },
}

3. Operator surfaces

Durable Objects do not appear on GET …/bindings or in Dashboard Storage. cellp’s binding parser only lists D1, KV, R2, Queues, Workflows, and Cron from wrangler. There is no cellp operator API for DO state — debug through Worker logs and your own metrics.

4. Preview vs production

Each version runs its own celld process and object bucket. Durable Object storage for a preview version is not branched from the parent like D1/KV/R2/Queue. A child version starts with empty DO state for that version’s runtime. Plan migrations and IDs accordingly.

Runtime gaps (celld)

Before shipping production traffic on DO:

• RPC stubs cannot cross isolate boundaries (see celld RPC notes).
• Outbound WebSockets do not survive object migration.
• Invalid UTF-8 in SQLite TEXT is rejected — store arbitrary bytes in BLOB.

Full matrix: celld cloudflare-compat — Durable Objects.

Related

Handlers · Supported stacks · Images (separate partial binding)