Because of xyz reasons, we don't have Service Provider (SP) to place SAML login request. So, here my question is will it be possible to login into SAML through IDP directly? If it is possible, could you please explain steps? We are using Webservices, please remind this.
The IdP can read SAML tokens but only when they are grouped using a profile. A common profile is the browser based WBSSO. So in order to talk to the IdP you need an SP. The SP just groups the SAML tokens into a profile the IdP can understand. Most SAML profiles are browser based but have a look at the ECP profile for non browser access https://wiki.shibboleth.net/confluence/display/CONCEPT/ECP