How to get repository branch commit

Hello

I want to get all commit via API for specific branch how I can get please help me 

I try this way

https://api.github.com/repos/andreagriffiths11/gis.utah.gov/commits?sha=metadata 

it gives the only repository response

if I change my repository then it will now allowed to me 

https://api.github.com/repos/DudhatShivam/Ecofactura-FEL/commits?sha=v12

this will not work

Thank you 

Shivam