Grant types

authorization_codeAn authorization code is returned to the client through a browser redirect after the resource owner (RO) gives consent to the AS. The client subsequently exchanges the authorization code for an access token and often a refresh token. RO credentials are never exposed to the client.

passwordThe client collects the RO’s password and exchanges it at the AS for an access token and often a refresh token. This grant type is suitable in cases where the RO has a trust relationship with the client, such as its computer operation system or a highly-privileged application because the client must discard the password after using it to obtain the access token.

refresh_tokenA refresh token often returns with an access token. Once the original access token expires, the corresponding refresh token sends to the AS to obtain a fresh access token without requiring the RO to re-authenticate. This allows short-lived access tokens to exist between the client and the resource server and long-lived tokens between the client and the AS.The refresh token grant type only works in conjunction with either the authorization code or RO password credentials grant type.

implicitA browser redirect responds to the RO authorization request, rather than an intermediate authorization code, and returns an access token to the client. This grant type works for clients incapable of keeping client credentials confidential for use in authenticating with the AS, such as client applications implemented in a browser using a scripting language like JavaScript.

client_credentialsThe client presents its own credentials to the AS to obtain an access token. This access token is either associated with the client’s own resources, and not a particular RO, or with a RO for whom the client is otherwise authorized to act.

urn:ietf:params:oauth:grant-type:saml2-bearerThe client obtains a SAML 2.0 Bearer assertion and uses it to request an access token from the AS. Similar to the JWT Bearer grant type, this grant type allows a client to use an existing trust relationship, expressed through a SAML assertion, without a direct user approval step at the AS.

urn:openid:params:grant-type:cibaThe client presents an identity hint to the AS. The AS identifies the RO based on the hint provided and then authenticates and obtains authorization from the RO through an out-of-band flow. Depending on the setup, the client either polls the AS for the authorization result or wait for a signal from the AS to return to the AS for the authorization result. If the RO approves the authentication request, the AS returns an access token to the client. Otherwise, the AS returns an error message per the specification.

urn:ietf:params:oauth:grant-type:device_codeThe client presents a device code and user code to the AS to identify the device-authorization session and obtain an access token. This access token is associated with a RO for whom the client is otherwise authorized to act.

urn:ietf:params:oauth:grant-type:token-exchangeThe client presents a security token to the AS. In exchange, the AS returns another kind of security token to the client. The new token might be an access token that is more narrowly scoped for a downstream service or it could be an entirely different kind of token. This grant type supports subject and actor tokens employing impersonation and delegation.

urn:pingidentity.com:oauth2:grant_type:validate_bearerThis proprietary PingFederate OAuth extension enables an RS to act as a client in the request/response exchange with PingFederate as the AS in this scenario. The grant type allows an RS to check with PingFederate on the validity of a bearer access token received from a client making a protected-resources call.