For Apple's APNS, what is the sandbox endpoint

Apple provides a sandbox endpoint that can be used for testing push notifications.  The sandbox ensures that device IDs in that environment will not work in production and are thus safe for testing purposes.

When do I need to select the sandbox endpoint?

You must specify the sandbox endpoint setting for both token-based (.p8) and certificate-based (.p12) authentication.

Use sandbox when:

• Testing with development builds from Xcode
• Using a development APNs certificate

Use production when:

• Distributing via App Store or TestFlight
• Using a distribution APNs certificate

Important: For certificate-based authentication, you are responsible for matching the endpoint selection with your certificate type:

• Development certificate → Select sandbox endpoint
• Distribution certificate → Select production endpoint

For more information about APNs environments, see Apple's documentation on sending notification requests to APNs.