Are there any limitations for the FCM topics names?

Question

I\'m trying to find out if there are any limitations for the topic names for FCM. Managed to find info about the number of topics (no limitations), but nothing like length o

Answer 1

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.