Durable Objects Move to Open Beta on Cloudflare Workers

Cloudflare has opened beta access to Durable Objects, the stateful serverless platform it first announced in September. Any developer with a Cloudflare Workers subscription can now enable the feature from the Workers section of the Cloudflare dashboard or deploy code using the latest version of Wrangler.

The beta is offered for testing purposes: storage is capped at 10 GB per account, and Cloudflare provides no SLA for object availability or durability during this period.

How Durable Objects Work

Durable Objects pair two capabilities: coordination across multiple Workers and strongly consistent edge storage. In Cloudflare's standard model, a Worker runs wherever the client request terminates, which can result in many Worker instances running concurrently across the network. A Durable Object, by contrast, is defined by a JavaScript class and an ID, and only one instance of a Durable Object with a given ID exists anywhere in the world at a time.

All Workers that make subrequests for a particular Durable Object ID are routed to that same instance. This enables coordination across requests, and the instance itself can call downstream APIs and persist data through Cloudflare's strongly consistent storage API.

A common pattern is to use a user ID as the Durable Object ID. A Worker that needs a given user's data contacts the object with that user's ID, and the object handles API calls and data access for that individual. Durable Objects scale across IDs, but each object runs on a single thread. Developers should choose IDs to minimize the number of requests that any one object must process. For a large user API, for example, an ID combining the user ID and an API endpoint could distribute load more evenly.

Pricing Model

Durable Objects are free during the beta, but Cloudflare has published pricing so developers can plan. Usage is billed for object compute time plus storage API operations, following the rates announced for Workers Unbound. Per-operating billing is metered in 4 KB increments: an 8 KB read or write counts as two operations, while deletes are not limited by size.

Storage is charged per GB-month. Cloudflare compares its per-operation prices favorably against AWS DynamoDB, noting that Durable Objects include multi-region replication and transactional consistency by default, capabilities that DynamoDB prices separately. The company also observes that most requests are smaller than 4 KB, citing Workers KV median value sizes in the low single-digit KB range.

Design Advantages Over Traditional Databases

Beyond cost, Durable Objects differ from a conventional database layer because each object runs custom developer code. After a Durable Object calls a downstream API or the storage API, results can be cached in-memory for low-latency, no-cost lookups. Data is replicated across distinct regions by default at no additional charge, and strong consistency across operations is included rather than sold as an upgrade.

Platform Updates Since Launch

Since the original announcement, Cloudflare has added several features:

  • Smarter initial placement for user-named objects, reducing latency immediately after creation.
  • Jurisdictional Restrictions, which constrain objects to run and store data only in specified regions for data localization compliance.
  • Wrangler support for uploading Durable Objects.
  • General platform stability and capacity increases.