api for buy/sell bitcoin – Bitcoin Stack Exchange

I have recently started a project to build an exchange plateform. I am unable to find an API that provides me an ability to implement a feature to buy and sell bitcoins.

Can someone please let me know

  1. if an api is available to provide this feature.

  2. also if i were to test it, how would i go towards testing that feature.

I have seen some api where there are end points available but it is very risky if end points are changed.

I will really appreciate your help.