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Pricing

When does a Durable Object incur duration charges?

A Durable Object incurs duration charges as long as the JavaScript object has to be in memory, either because it is actively handling a request, or because it cannot hibernate.

Once an object has been evicted from memory, the next time it is needed, it will be recreated (calling the constructor again).

There are several factors that contribute in keeping the Durable Object in memory and keeping it from hibernating or being inactive. Find more information in Lifecycle of a Durable Object.

Does an empty table / SQLite database contribute to my storage?

Yes, although minimal. Empty tables can consume at least a few kilobytes, based on the number of columns (table width) in the table. An empty SQLite database consumes approximately 12 KB of storage.

Does metadata stored in Durable Objects count towards my storage?

All writes to a SQLite-backed Durable Object stores nominal amounts of metadata in internal tables in the Durable Object, which counts towards your billable storage.

The metadata remains in the Durable Object until you call deleteAll().

Limits

How much work can a single Durable Object do?

Durable Objects can scale horizontally across many Durable Objects. Each individual Object is inherently single-threaded.

  • An individual Object has a soft limit of 1,000 requests per second. You can have an unlimited number of individual objects per namespace.
  • A simple storage get() on a small value that directly returns the response may realize a higher request throughput compared to a Durable Object that (for example) serializes and/or deserializes large JSON values.
  • Similarly, a Durable Object that performs multiple list() operations may be more limited in terms of request throughput.

A Durable Object that receives too many requests will, after attempting to queue them, return an overloaded error to the caller.

How many Durable Objects can I create?

Durable Objects are designed such that the number of individual objects in the system do not need to be limited, and can scale horizontally.

  • You can create and run as many separate Durable Objects as you want within a given Durable Object namespace.
  • There are no limits for storage per account when using SQLite-backed Durable Objects on a Workers Paid plan.
  • Each SQLite-backed Durable Object has a storage limit of 10 GB on a Workers Paid plan.
  • Refer to Durable Object limits for more information.

Can I increase Durable Objects' CPU limit?

Durable Objects are Worker scripts, and have the same per invocation CPU limits as any Workers do. Note that CPU time is active processing time: not time spent waiting on network requests, storage calls, or other general I/O, which don't count towards your CPU time or Durable Objects compute consumption.

By default, the maximum CPU time per Durable Objects invocation (HTTP request, WebSocket message, or Alarm) is set to 30 seconds, but can be increased for all Durable Objects associated with a Durable Object definition by setting limits.cpu_ms in your Wrangler configuration:

{
  // ...rest of your configuration...
  "limits": {
    "cpu_ms": 300000, // 300,000 milliseconds = 5 minutes
  },
  // ...rest of your configuration...
}