TencentCloud / TIMSDK

Free Chat SDK (IM SDK) — 1,000 MAU/month free forever with push notifications & no concurrency limits. Build in-app messaging with chat API, UIKit & send message. Supports Android, iOS, Flutter, Web, React Native, uni-app, HarmonyOS & more.

OneSignal / OneSignal-Flutter-SDK

OneSignal makes engaging customers simple and is the fastest, most reliable service to send push notifications, in-app messages, SMS, and emails. This plugin makes it easy to integrate your Fluter app with OneSignal. https://onesignal.com

OneSignal / OneSignal-Android-SDK

OneSignal makes engaging customers simple and is the fastest, most reliable service to send push notifications, in-app messages, SMS, and emails. This plugin makes it easy to integrate your native Android or Amazon app with OneSignal. https://onesignal.com