Which is a good mobile application development company (outsourced) specifically for chat apps?

There are numerous mobile app development companies in the world that can develop a chat app for you. I had taken a mobile app development service from one agency in India a year and I saw some chat apps developed by them during their portfolio analysis.

Also, I found an article they had prepared for chat app development and it is worth reading as it will give you an insight on Chat app Development. You can refer to the article below

https://www.webcluesinfotech.com/cost-to-develop-a-chat-app/

Also, they have mentioned past work on chat app development in the article itself so do read it.