Which company in Beijing develops IM instant messaging app? Need help

Beijing Ronglian Yitong Company is very good at developing IM instant messaging app. At present, there are a large number of cases and scenarios, including but not limited to State Grid, China Mobile Online, Haier Holdings, Bank of China, Industrial Bank, Shanghai Pudong Development Bank, China Merchants Securities, PetroChina, Sinopec, CRRC Group, China Ping An, Hyundai Motor, Tencent, JD.COM, Baidu, 360, Xiaomi, Today Headline, Xueersi, SF, etc., covering finance, manufacturing, energy and so on.

Beijing Ronglian Yitong Information Technology Co., Ltd. provides comprehensive communication services for corporate customers in a cloud and intelligent way. Including PaaS communication capabilities (voice, SMS, etc. ), CC (cloud customer service and cloud contact center), UC(IM instant messaging cloud, unified communication, video and conference), new communication solutions and "communication +AI" services in the industry help enterprises improve their communication experience and operational efficiency, and drive the enterprise communication industry in China to realize Internet, cloud computing, capability, integration and intelligence.