Push notifications FAQs

Answers to frequently asked questions about Ably's push notification service.

Connection and network

FAQs related to network connectivity and debugging connection issues.

How can I confirm network access to Ably?

Use the following curl command to debug connection issues. It retrieves the current time from the Ably REST API and provides detailed output about the TLS key exchange, SSL certificate verification, and HTTP headers:

curl -v -s -w "time_namelookup: %{time_namelookup}
time_connect: %{time_connect}
time_appconnect: %{time_appconnect}
time_pretransfer: %{time_pretransfer}
time_redirect: %{time_redirect}
time_starttransfer: %{time_starttransfer}
time_total: %{time_total}" \
https://rest.ably.io/time

Repeat this process for fallback hosts to verify network connectivity to them. Fallback hosts are used automatically if the primary endpoint fails.

The output includes items prefixed with * (certificate exchange), > (request), and < (response). Timings are computed from the -w statistics and help identify bottlenecks in the connection process.

Platform configuration

FAQs related to configuring push notifications for specific platforms.

For Apple's APNs, what is the sandbox endpoint?

Apple provides a sandbox endpoint for testing push notifications. This ensures device IDs in that environment do not work in production.

Customers often have a test/sandbox app using the APNs sandbox endpoint and a production app that does not. When setting up push notifications in your dashboard, enable the sandbox endpoint in the APNs settings if you intend to use it.

Billing and limits

FAQs related to push notification costs and connection limits.

Do push subscriptions count as connections?

No. Push notifications do not require a device or browser to stay connected to Ably, so they do not count as a connection.

However, publishing a push notification via a channel activates that channel. Therefore, your concurrent (peak) channel count includes the number of channels you simultaneously publish to.

Does Ably charge for push notifications?

Yes. Each push notification delivered to a device counts as one normal message.

Troubleshooting

FAQs related to debugging and resolving push notification issues.

How do I debug push notifications?

If you are not receiving expected push notifications, the issue may lie with Ably, FCM, APNs, or device configuration.

Verify device registration with Ably

Follow these steps to check if your device is correctly registered with Ably:

Check for errors

Errors publishing to FCM or APNs are recorded in the meta channel [meta]log:push.

If there are no errors, the notification was successfully sent to the push provider.

Specific errors

Why are my push notifications duplicated?

Consistent duplication on a specific device usually indicates both a deviceId and a clientId subscription to the push channel. Remove one to prevent duplication.

• DeviceId subscriptions: Deliver to a single device.
• ClientId subscriptions: Deliver to all devices identified by that clientId.

Why can I not publish push notifications on channels?

If you're unable to publish push notifications to channels, this is typically due to configuration or permission issues. The following are possible reasons for this issue:

1. Channel Rules: Channels must be explicitly enabled for push notifications via channel rules. They are disabled by default.
2. Permissions: The publisher must have permission to publish to that channel.
3. Invalid Payload: If the push notification payload in the extras field is invalid, the message may be rejected immediately.