Salesforce: How to get the access token expires_at

Salesforce's token endpoint deviates from standard OAuth conventions by not including the "expires_at" parameter, which indicates when an access token expires. To determine the expiration date, users must make an additional API request to a token introspection endpoint, which provides details such as the token's expiration time in a Unix timestamp format. The lack of expiration information complicates the process of refreshing access tokens, which should ideally be refreshed well before they expire to avoid potential API request failures. To address these challenges, Nango, an open-source API authorization solution, offers pre-built implementations for Salesforce OAuth and automates processes like access token refreshes and secure token storage, easing the integration burden for developers.