durable-objects

Stateful coordination logic using Cloudflare Durable Objects is built by modeling coordination atoms like one DO per chat room or tenant, configuring wrangler bindings, implementing typed RPC methods, and validating behavior with Vitest worker pools.

The best way to structure SQLite storage for Durable Objects is to write critical state to SQLite first before responding, configure migrations through wrangler, and follow concurrency-safe patterns to ensure reliable per-entity persistence.

You test Durable Objects alarms and WebSocket behavior using the @cloudflare/vitest-pool-workers package, which supports unit tests, integration tests, and alarm verification to validate stateful edge workflows.

You should use blockConcurrencyWhile only for initialization tasks in a Durable Object to prevent concurrent requests from interfering, ensuring deterministic routing and consistent state setup.

You schedule alarms idempotently for a Durable Object by limiting it to one alarm per DO instance and using the storage and alarms patterns to manage scheduled stateful workflows reliably.

Yes, you can and should prefer typed RPC methods over fetch handlers for Durable Objects to cleanly expose stateful coordination logic for applications like multiplayer sessions and bookings.