I have a website that has users from both Hong Kong and Australia.

Unfortunately, since the server is located in Australia, users from Hong Kong are going to suffer latency problems. Traffic has to go through US before travelling back to Australia.

So I've setup a server in Hong Kong as well, and users using the .hk TLD are going to be redirected to the Hong Kong web server. It shares the same database server with the Australian server but due to aggressive SQL query caching, impact on performance from latency from SQL queries are negligible.

But for users accustomed to the Hong Kong website but have since traveled to Australia, they suffer from additional latency because they go to the .hk site which redirects to the HK server even when they're in Australia. The website is targeted at international students from Hong Kong so this is an significant issue for me.

Instead of redirecting users to the closest web server based on the TLD, how do I redirect users based on their location?

Currently I am using nginx, postgres and Django. Say I know how to estimate users' location based on users' IP addresses, what is my next step? At what level would I work on? What topic should I read up?