According to VentureBeat, high mobile penetration, geographic closeness to China and India, horizontal platforms, strong social impact, and a rich culture are just some of the reasons devs are choosing SE Asia
These days, developers have options outside of that narrow strip of land between San Francisco and San Jose. In the past 10 years, the international tech scene has grown to the point that developers can find a home in Tel Aviv, Toronto, Amsterdam, or Berlin — all burgeoning tech hubs. However, if a developer wants interesting work, there’s another place to look: Southeast Asia. A diverse region bordered by China to the north and India to the west, Southeast Asia is home to some of the world’s fastest growing economies, including Indonesia, Malaysia, and Singapore. Mobile phone penetration in the region is already at 110 percent, and Internet penetration, though still low, grew by more than 10 percent in 2016. All this has given rise to a thriving tech startup ecosystem.
https://venturebeat.com/2017/06/25/3-reasons-southeast-asia-is-a-great-place-for-developers/