我想知道是否有提供各种 Firebase FCM 使用限制详细信息的综合列表。

我知道最大 4KB 的数据消息有效负载限制。
然后最近我的应用程序出现了一些问题，然后认为这是由于另一个限制 -"每个设备最多 4 个不同的折叠键"。

我还记得在最近的一次谈话中，谷歌提到他们已经取消了一些他们以前喜欢的主题数量等限制。

我正在尝试详细了解 Google 对 FCM 使用实施的所有各种限制。

这里是 Firebase 支持人员给出的答案：

Firebase Cloud Messaging is free of charge, no matter the number of users and message pushes, just like Google Cloud Messaging was.
However, here are some of its product"limitation":
There's a limit of 1000 registration tokens used when using registration_ids parameter per send. So if you want to send 5000 messages to different users, you'll need to send the message in 5 batches. There's a limit of 100 messages that can be stored without collapsing. You can read more details here.
You may also encounter limitations such as sending too much messages per second. Aside from that, everything in FCM is free and unlimited.

We currently don't have an SLA for FCM since it's a free service. We could never guarantee the delivery of messages since we do not control the networks between our servers and the device. We also offer the same level of support for both our paid and free plans for this service. Kindly see our Pricing FAQ here, under"What kind of support will I receive?" for more information.

FCM 文档现在包含有关限制和缩放的信息。详细信息包括：

• 可折叠消息限制
• XMPP 服务器限制
• 单个设备的最大消息速率

• 上行消息限制

• 主题消息限制

最大有效负载记录在同一页面上，此处以及折叠键限制：

...the FCM server can simultaneously store four different collapsible
messages per device, each with a different collapse key. If you exceed
this number, FCM only keeps four collapse keys, with no guarantees
about which ones are kept.

与限制相关的常见错误包括 messaging/device-message-rate-exceeded 或 messaging/topics-message-rate-exceeded。可以在此处找到有关错误消息的更多详细信息。

所以根据我的评论，它与 GCM 几乎相同。因此，如果需要，您可以继续阅读这篇文章。但不要去那里提到的 GCM 文档，你应该继续检查 FCM - 消息的生命周期。

或者您指的是更具体的限制，例如实时数据库连接/GB 存储限制(您可以去查看他们的定价。

除非您试图找到更复杂或不同的东西，否则我认为您可以在文档中找到您最初需要的几乎所有内容。干杯！