# Instance API

API Reference for Instance

> **Terminology Update:** We have streamlined our naming conventions to improve clarity. The term **Instance** has been replaced with **Instance**. To avoid breaking changes the APIs still make use of the old term. Both terms refer to the same underlying functionality.

## Update Target

Update Target: Update an existing target. To generate a new signing key set the optional `expirationSigningKey`. Required permission: [Update Target](/content/docs/reference/api/action/zitadel.action.v2.ActionService.UpdateTarget)

## Add Custom Domain

Add Custom Domain: Adds a Custom Domain to the instance. The Custom Domain must be unique across all instances. Once the domain is added, it will be used to route requests to this instance. This method requires system permissions. [Add Custom Domain](/content/docs/reference/api/instance/zitadel.instance.v2.InstanceService.AddCustomDomain)

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