Use following Steps To get SMS API & Sample Code:
1) Login in our SMS portal For Login Process visit here.
2) Inside Login left side in Menu below of delivery report option you can get API option click on that.
3) After that, you can get there your auth key and click on SMS API documentation option for sample code.
4) After clicking the API Documentation option you can get sample code on the top menu bar you can click on that & take your code and try to integrate.