How to make an internet speed tester like ookla or fast.com(Netflix). And which language do we use?

Answer 1

A rough idea is to download a file, let's say 1 MB in size, record the time of beginning and end of download.

Next calculate the seconds taken for downloading the said file, and then measure how many bits or kilobits or megabits is actually downloaded per second.

Answer 2

I can't recommend a specific language, just that rough idea. I think any language that supports file download plus a bit of maths will do (just my opinion).

Answer 3

But which language do we use?