You can also initiate the authentication session the SAML single sign-on action through a POST request. The following sample shows the POST /{environmentId}/saml20/idp/sso operation to start the sign-on flow:

The request URL includes the SAMLRequest parameter to pass in the encoded SAML authorization request information. Here is a sample SAML <AuthnRequest> in plain text:

<samlp:AuthnRequest Destination="https://auth.pingone.com/e1b1d03e-3463-4cfc-9708-32543093acb5/saml20/idp/sso" ID="I01_HYEnkEP4h6yfnKITWyDDfhBOIAL0aW7VEp1mSqXLstFZ2XueJy5M8VWRXa" IssueInstant="2020-02-25T05:43:56.329Z" Version="2.0" xmlns:samlp="urn:oasis:names:tc:SAML:2.0:protocol">
  <saml:Issuer xmlns:saml="urn:oasis:names:tc:SAML:2.0:assertion">http://pingone.com/565145b9-f52a-4fed-b114-5e97c5b35ea7</saml:Issuer>
</samlp:AuthnRequest>