OAuth refresh token flow and OAuth JWT bearer token flow are the recommended best practices for using OAuth flows inthis scenario. These flows are suitable for server-to-server integration scenarios where the client application needs to access Salesforce resources on behalf of a user. The OAuth refresh token flow allows the client application to obtain a long-lived refresh token that can be used to request new access tokens without requiring user interaction. The OAuth JWT bearer token flow allows the client application to use a JSON Web Token (JWT) to assert its identity and request an access token. Both flows providea secure and efficient way to integrate with Salesforce and the reward calculation system. OAuth SAML bearer assertion flow is not a recommended best practice for using OAuth flows in this scenario because it requires the client application to obtain a SAML assertion from an identity provider, which adds an extra layer of complexity and dependency. OAuth username-password flow is not a recommended best practice for using OAuth flows in this scenario because it requires the client application to store the user’s credentials, which poses a security risk and does not support two-factor authentication. References: : [Which OAuth Flow to Use] : [Digging Deeper into OAuth 2.0 on Force.com] : [OAuth 2.0 JWT Bearer Token Flow] : [OAuth 2.0 SAML Bearer Assertion Flow] : [OAuth 2.0 Username-Password Flow]