Salesforce Marketing Cloud FuelSDK Auth

Node.js library for OAuth2 authentication with Salesforce Marketing Cloud (formerly ExactTarget) REST and SOAP APIs. Version 3.3.0 targets Node >= 4, uses request package for HTTP, and is ESM-only with TypeScript declarations. It simplifies obtaining access tokens using client credentials or refresh tokens. Compared to manual OAuth2 flows, it handles token caching, refresh, and error handling. The library is actively maintained by Salesforce but has limited updates for newer Node versions.