We want to authentication without click authentication url link

we want to authentication without click authentication url link.
we work on back-end and not want to open login form for authentication. want to direct login using username and password. using curl or api internal action. please suggest me.

Hi @Rajesh_s, if you sign in to Account Central, there should be an “API Access” link next to your application. If you click that, you will be able to enter in your client_id and client_secret to generate an access token and refresh token. From there you can use this access token to hit the REST or XML-RPC API. This method will not require you to go through the traditional OAuth flow in order to retrieve an access token.