Which protocol is commonly used for authentication in APIs built with MuleSoft?

The commonly used protocol for authentication in APIs built with MuleSoft is OAuth 2.0. This protocol is widely recognized and utilized for authorizing access in web applications and APIs. OAuth 2.0 enables third-party applications to obtain limited access to an HTTP service on behalf of a user, without sharing the user's credentials.

Through mechanisms such as access tokens, OAuth 2.0 facilitates secure and delegated access, allowing APIs to interact with user data without exposing sensitive information. This level of security and flexibility makes it the preferred choice in modern API development, particularly within the MuleSoft ecosystem, where robust API integration is essential.

In contrast, while FTP, SOAP, and SMTP are protocols that can serve various functions within network communications, they do not address API authentication needs effectively. FTP is primarily used for file transfers, SOAP is a protocol for exchanging structured information in web services, and SMTP is designed for sending emails. These protocols do not encompass authentication mechanisms suitable for API security in the way that OAuth 2.0 does.