Is FCM token secret?

According to this link, the registration token must be kept secret . Registration token: An ID generated by the FCM SDK for each client app instance. Required for single device and device group messaging. Note that registration tokens must be kept secret.

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What is FCM device token?

Firebase Cloud Messaging (FCM) is a messaging solution that lets you reliably send messages at no cost to both Android & iOS devices . Using FCM, you can send data payloads (via a message) to a device for a specific application. Each message can transfer a payload of up to 4KB to a client.

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Does FCM token change?

To cover all cases, you should adopt a threshold for when you consider tokens stale; our recommendation is two months. Any token older than two months is likely to be an inactive device; an active device would have otherwise refreshed its token .

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