eWeLink platform is a smart home assistant app and cloud based platform for users worldwide, based on the global eWeLink IoT platform, serving 15 million registered users from 150 countries.
Many brands offer eWeLink platform and app compatible devices, but the major brand of the platform is SONOFF. Other brands include SmartWise, WDYK, Woolley and some others unbranded. As they all use the same platform and eWeLink app, they can easy work together in cross-brand scenes and automations.
By connecting to eWeLink platform and APP, these products of different types from various brands are put under control and management in one app. Furthermore, eWeLink partners with multiple voice assistants (such as Google Assistant and Amazon's Alexa, or Apple's Siri, so it is easy to voice control these devices.
eWeLink APP is free, and is available on Android and iOS platforms.
Recently, eWeLink also started to offer solutions without cloud connectivity. Some gateway, such as Sonoff Zigbee Pro gateway needs internet connection and cloud access for setup, but can continue to run local Zigbee automations from cache when internet connection is lost.
Sonoff has also released recently a local hub, called Sonoff iHOST, which can syncronize the user's cloud connected eWeLink devices, and make these cloud devices local by running the scenes and automations locally from now on.
eWeLink devices support a number of different communication protocols, such as Wi-Fi and Zigbee. For local remote control and data transfer they may use either RF433 (older devices) or eWeLink-Remote, a Bluetooth-based prorietary technology.
Most eWeLink devices store up to 8 scheduled actions (such as on/off) locally, so time-based automations can also run in case of offline mode. Additional schedules and scenes (automations) run from either from the cloud (by default), or a local hub such as Sonoff iHOST.
Sonoff and other eWeLink compatible brands are also famous for their easy integration to open source home automation platforms, such as Home Assistant. Also, open source firmwares, such as Tasmota or ESPHome, is available for most eWeLink devices, so factory firmware can also be reflashed by the DIY smart home owners.