When needing to securely expose an external system, which capability of Canvas is most vital?

The most vital capability of Canvas when needing to securely expose an external system is signing requests. This capability ensures that the requests made to the external system are authenticated and have not been tampered with. By signing requests, the system can validate that the request originates from a legitimate source, preserving the integrity and security of the communication between systems.

Signing requests safeguards against various security threats, such as replay attacks or unauthorized access. It serves as a foundational layer for secure interactions, ensuring that only privileged or authorized entities can send requests to the external system.

While data visualization, asynchronous communication, and session management are important capabilities within the context of Canvas, they do not directly address the need for secure exposure of an external system. Data visualization focuses on representing data effectively, asynchronous communication manages the timing of interactions, and session management relates to handling user sessions. However, none of these features provide the essential security measures that come with signing requests, which is crucial for maintaining trust and safety in system integrations.