[[["เข้าใจง่าย","easyToUnderstand","thumb-up"],["แก้ปัญหาของฉันได้","solvedMyProblem","thumb-up"],["อื่นๆ","otherUp","thumb-up"]],[["ไม่มีข้อมูลที่ฉันต้องการ","missingTheInformationINeed","thumb-down"],["ซับซ้อนเกินไป/มีหลายขั้นตอนมากเกินไป","tooComplicatedTooManySteps","thumb-down"],["ล้าสมัย","outOfDate","thumb-down"],["ปัญหาเกี่ยวกับการแปล","translationIssue","thumb-down"],["ตัวอย่าง/ปัญหาเกี่ยวกับโค้ด","samplesCodeIssue","thumb-down"],["อื่นๆ","otherDown","thumb-down"]],["อัปเดตล่าสุด 2025-09-06 UTC"],[],[],null,["FCM topic messaging lets you to send a message to multiple devices\nthat have opted in to a particular topic. You compose topic messages as needed,\nand FCM handles routing and delivering the message reliably to the\nright devices.\n\nKey points about topic messaging:\n\n- Best suited for publicly available information like weather alerts.\n- Topic messages are optimized for throughput rather than latency. For fast, secure delivery to single devices or small groups, [target messages](/docs/cloud-messaging/send-messages/send/v1-api#send-messages-to-specific-devices) to registration tokens instead of topics.\n- Topic messaging supports unlimited subscriptions per topic, with the following limits:\n - An app instance can subscribe to a maximum of 2000 topics.\n - Batch subscription requests for subscribing app instances are limited to 1000 instances per request.\n - New subscription frequency is rate-limited per project. Exceeding the limit results in a `429\n RESOURCE_EXHAUSTED` error; retry with exponential backoff.\n\nQuotas and limits\n\nTopic messaging supports unlimited subscriptions for each topic. However,\nFCM enforces limits in these areas:\n\n- One app instance can be subscribed to no more than 2000 topics.\n- If you are using [batch subscription](https://developers.google.com/instance-id/reference/server#manage_relationship_maps_for_multiple_app_instances) to subscribe app instances, each request is limited to 1000 app instances.\n- 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.\n\nNext Steps\n\n- Learn how to [Manage Topic Subscriptions](/docs/cloud-messaging/doc-revamp/targeting-user-groups/manage-topic-subscriptions) using the Admin SDK or from your client app.\n- Learn how to [Send Messages to Topics](/docs/cloud-messaging/doc-revamp/targeting-user-groups/send-topic-messages) using the Admin SDK or the FCM v1 HTTP API."]]
