---
description: API reference for DurableObjectId, the 64-digit hex identifier used to address a Durable Object.
title: Durable Object ID
image: https://developers.cloudflare.com/og-docs.png
---

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# Durable Object ID

Last updated Aug 24, 2026|Copy as Markdown|[View as Markdown](https://9a51ac8b.previews.developers.cloudflare.com/durable-objects/api/id/index.md)|[Agent setup](https://9a51ac8b.previews.developers.cloudflare.com/agent-setup/)

## Description

A Durable Object ID is a 64-digit hexadecimal number used to identify a Durable Object. Not all 64-digit hex numbers are valid IDs. Durable Object IDs are constructed indirectly via the [DurableObjectNamespace](https://9a51ac8b.previews.developers.cloudflare.com/durable-objects/api/namespace) interface.

The `DurableObjectId` interface refers to a new or existing Durable Object. This interface is most frequently used by [DurableObjectNamespace::get](https://9a51ac8b.previews.developers.cloudflare.com/durable-objects/api/namespace/#get) to obtain a [DurableObjectStub](https://9a51ac8b.previews.developers.cloudflare.com/durable-objects/api/stub) for submitting requests to a Durable Object. Note that creating an ID for a Durable Object does not create the Durable Object. The Durable Object is created lazily after creating a stub from a `DurableObjectId`. This ensures that objects are not constructed until they are actually accessed.

Logging

If you are experiencing an issue with a particular Durable Object, you may wish to log the `DurableObjectId` from your Worker and include it in your Cloudflare support request.

## Methods

### `toString`

`toString` converts a `DurableObjectId` to a 64 digit hex string. This string is useful for logging purposes or storing the `DurableObjectId` elsewhere, for example, in a session cookie. This string can be used to reconstruct a `DurableObjectId` via `DurableObjectNamespace::idFromString`.

```js
// Create a new unique ID
const id = env.MY_DURABLE_OBJECT.newUniqueId();
// Convert the ID to a string to be saved elsewhere, e.g. a session cookie
const session_id = id.toString();

...
// Recreate the ID from the string
const id = env.MY_DURABLE_OBJECT.idFromString(session_id);
```

#### Parameters

* None.

#### Return values

* A 64 digit hex string.

### `equals`

`equals` is used to compare equality between two instances of `DurableObjectId`.

```js
const id1 = env.MY_DURABLE_OBJECT.newUniqueId();
const id2 = env.MY_DURABLE_OBJECT.newUniqueId();
console.assert(!id1.equals(id2), "Different unique ids should never be equal.");
```

```python
id1 = env.MY_DURABLE_OBJECT.newUniqueId()
id2 = env.MY_DURABLE_OBJECT.newUniqueId()
assert not id1.equals(id2), "Different unique ids should never be equal."
```

#### Parameters

* A required `DurableObjectId` to compare against.

#### Return values

* A boolean. True if equal and false otherwise.

## Properties

### `name`

`name` is an optional property of a `DurableObjectId`, which returns the name that was used to create the `DurableObjectId` via [DurableObjectNamespace::idFromName](https://9a51ac8b.previews.developers.cloudflare.com/durable-objects/api/namespace/#idfromname). This value is undefined if the `DurableObjectId` was constructed using [DurableObjectNamespace::newUniqueId](https://9a51ac8b.previews.developers.cloudflare.com/durable-objects/api/namespace/#newuniqueid).

The `name` property is also available on `ctx.id` inside the Durable Object when the caller uses `idFromName()` or `getByName()`. `ctx.id.name` will be `undefined` in the following cases:

* The caller accesses the Durable Object using `idFromString()`, even if the ID was originally created with `idFromName()`.
* Names longer than 1,024 bytes are not passed through to `ctx.id`.
* The Durable Object was created with `newUniqueId()`.

Alarms

`ctx.id.name` is especially useful inside [alarm handlers](https://9a51ac8b.previews.developers.cloudflare.com/durable-objects/api/alarms/), where there is no calling client to pass the name as an argument. When the alarm fires, `ctx.id.name` holds the same name the object was originally accessed with.

Alarms created before 2026-03-15 do not have `name` stored. When such an alarm fires, `ctx.id.name` will be `undefined`, and any new alarm scheduled from that handler will also lack a `name`. To fix this, reschedule the alarm from a `fetch()` or RPC handler where `name` is available.

```js
const uniqueId = env.MY_DURABLE_OBJECT.newUniqueId();
const fromNameId = env.MY_DURABLE_OBJECT.idFromName("foo");
console.assert(uniqueId.name === undefined, "unique ids have no name");
console.assert(
	fromNameId.name === "foo",
	"name matches parameter to idFromName",
);
```

```ts
const uniqueId: DurableObjectId = env.MY_DURABLE_OBJECT.newUniqueId();
const fromNameId: DurableObjectId = env.MY_DURABLE_OBJECT.idFromName("foo");
console.assert(uniqueId.name === undefined, "unique ids have no name");
console.assert(
	fromNameId.name === "foo",
	"name matches parameter to idFromName",
);
```

```python
unique_id = env.MY_DURABLE_OBJECT.newUniqueId()
from_name_id = env.MY_DURABLE_OBJECT.idFromName("foo")
assert unique_id.name is None, "unique ids have no name"
assert from_name_id.name == "foo", "name matches parameter to idFromName"
```

The same `name` is available inside the Durable Object via `ctx.id.name`:

```js
import { DurableObject } from "cloudflare:workers";

export class ChatRoom extends DurableObject {
	async getRoomName() {
		return this.ctx.id.name; // "foo" when accessed via getByName("foo")
	}
}
```

```ts
import { DurableObject } from "cloudflare:workers";

export class ChatRoom extends DurableObject<Env> {
	async getRoomName(): Promise<string | undefined> {
		return this.ctx.id.name; // "foo" when accessed via getByName("foo")
	}
}
```

```python
from workers import DurableObject

class ChatRoom(DurableObject):
    async def get_room_name(self):
        return self.ctx.id.name  # "foo" when accessed via get_by_name("foo")
```

### `jurisdiction`

`jurisdiction` is an optional property of a `DurableObjectId`, which returns the [jurisdiction](https://9a51ac8b.previews.developers.cloudflare.com/durable-objects/reference/data-location/#restrict-durable-objects-to-a-jurisdiction) the ID is restricted to, such as `"eu"` or `"fedramp"`. The same value is available inside the Durable Object via `ctx.id.jurisdiction`, including in [alarm handlers](https://9a51ac8b.previews.developers.cloudflare.com/durable-objects/api/alarms/) and objects accessed via `idFromString()`, so you can make region-aware decisions without passing the jurisdiction as an argument or persisting it in storage.

`jurisdiction` is preserved across every ID-construction path, including:

* IDs created from a jurisdiction-restricted subnamespace, for example `env.MY_DURABLE_OBJECT.jurisdiction("eu").idFromName("foo")` or `.newUniqueId()`.
* IDs created via `env.MY_DURABLE_OBJECT.newUniqueId({ jurisdiction: "eu" })`.
* IDs restored from a string via `idFromString()` — the jurisdiction is encoded in the string itself, so it works on any namespace binding.

`ctx.id.jurisdiction` is `undefined` in two cases:

* The Durable Object was not created in a jurisdiction-restricted namespace.
* The Durable Object's alarm was scheduled before 2026-03-15\. To backfill the value, reschedule the alarm from a `fetch()` or RPC handler.

```js
const plainId = env.MY_DURABLE_OBJECT.idFromName("foo");
const euId = env.MY_DURABLE_OBJECT.jurisdiction("eu").idFromName("foo");
console.assert(plainId.jurisdiction === undefined, "no jurisdiction set");
console.assert(euId.jurisdiction === "eu", "jurisdiction matches namespace");
```

```python
plain_id = env.MY_DURABLE_OBJECT.idFromName("foo")
eu_id = env.MY_DURABLE_OBJECT.jurisdiction("eu").idFromName("foo")
assert plain_id.jurisdiction is None, "no jurisdiction set"
assert eu_id.jurisdiction == "eu", "jurisdiction matches namespace"
```

## Related resources

* [Durable Objects: Easy, Fast, Correct – Choose Three ↗](https://blog.cloudflare.com/durable-objects-easy-fast-correct-choose-three/).

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