Are there limitations for downstream message in firebase FCM? - firebase

I'm developing an android app that relies on realtime notifications using Firebase FCM.
I know that there are many limitations for upstream messaging using FCM, but I don't know if some sort of limitations exists for downstream messages (e.g. the number of requests per day)
Thank's in advance for the replies.

The use of Firebase Cloud Messaging is free and unlimited. There is no documented limit to the number of messages you can send per day.
There are limits in place to prevent abuse of the service, but those are not documented. If you think you are hitting such a limit and have a valid use-case, reach out to Firebase support for personalized help in troubleshooting.

Related

Can Firebase Cloud Messaging (FCM ) be configured to use specific server region for data processing/storing?

How does FCM Backend process or store data?
I have my own backend for handling and sending notifications via Firebase admin SDK.
I need to know is there a way to configure FCM to use only EU servers?
I have tried, but did not found anything. Maybe someone knows answer, since support will take 1-2 days to answer my ticket

Flutter FCM Topic named like a document

I am new to firebase cloud messaging and i search the best way to send notifications to clients.
I want people to be able to subscribe to new entry in subcollection like this :
books/{bookID}/comments/{commentId}/reply/{replyId}}
Is that bad if i use that kind of syntax?
so i can push notification on that topic when new reply are created
void fcmSubscribe(String bookId,String commentId) {
firebaseMessaging.subscribeToTopic('book-${bookiD}_comment-${commentId}');
}
or i need to use Individual Device Notifications and create entries like this
books/{bookID}/comments/{commentId}/notifications/{tokenId}}
i want to avoid firestore Read and Write.
You can use whatever valid topic names that you want. Use whatever you like - it's your choice. There is nothing particularly "bad" about your choice of name, as long as it works for you. Things can only go badly for you if you exceed one of the documented limits for topic messaging:
Topic messaging supports unlimited subscriptions for each topic. However,
FCM enforces limits in these areas:
One app instance can be subscribed to no more than 2000 topics.
If you are using batch import to subscribe app instances, each request is limited to 1000 app instances.
The frequency of new subscriptions is rate-limited per project. If you send too many subscription requests in a short period of time, FCM
servers will respond with a 429 RESOURCE_EXHAUSTED ("quota exceeded")
response. Retry with exponential backoff.
If you're thinking that FCM is tied in any way to Firestore, that's not the case. You are not obliged to make anything match between your Firesore documents and your FCM topics.

Does Firebase Cloud Messaging have an option to limit maximum no. of notifications sent per user per day?

We use FCM to send app notifications. Basically, we want to put a cap on maximum number of notifications that an app user can get in a day. Does FCM have an option where on hitting the cap, the subsequent messages are discarded by FCM and not sent to the user?
FCM is a free service which currently doesn't have any limitations whatsoever when it comes to the count of notifications sent and received.
If you want to enforce a limit of some sort, you would have to enforce this on your implementation (probably server side), by preventing further messages when a specific range is hit.
In general, push notification features are good for letting users know of specific (non-critical) information. I don't get why anyone would limit something when it's already free of use -- unless there's some different cost you're limiting which is directly affected by the push notif service.

How many topics an app instance can subscribe in FCM?

As mentioned in FCM documents, unlimited topic can be created for one Firebase application. But as the Firebase Admin SDK document: explains an error:
messaging/too-many-topics:- A registration token has been subscribed to the maximum number of topics and cannot be subscribed to any more.
I was not able to find this threshold value of maximum number of topics. Can anybody explain, what is the limit? How many topics an app instance can subscribe to in FCM?
I found the answer by running a subscription script for an app instance. After subscribing to 1999 topics, for the next subscription it started giving error: messaging/too-many-topics.
So the threshold value is 1999.
As much as the selected answer is correct, I'll like to post an absolute answer here.
Google Firebase Cloud Messaging
Some things to keep in mind about topics:
Topic messaging supports unlimited subscriptions for each topic.
However, FCM enforces limits in these areas:
One app instance can be subscribed to no more than 2000 topics.
If you are using batch import to subscribe app instances, each request is limited to 1000 app instances.
The frequency of new subscriptions is rate-limited per project. If you send too many subscription requests in a short period of time, FCM servers will respond with a 429 RESOURCE_EXHAUSTED ("quota exceeded") response. Retry with exponential backoff.

Curiosity: Why does Firebase not guarantee order of delivery for push messages?

I've been working with FB Messaging for a little while now and I came across something in the docs that made me curious as to what the reasoning is behind this behaviour:
There is no guarantee of the order in which messages get sent.
It's mentioned a couple of times throughout the documentation but this is one of the places: MessagingOptions (under collapseKey)
I've been wondering why Firebase doesn't just send the messages in the order they are received on their servers?
Is this just Google's (Firebase) Cloud Messaging platform works? Does it have to do with performance and efficiency?

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