How can a flow be accessed within an external custom app?

Embedding a flow using Lightning Out is the right approach for accessing a flow within an external custom app, particularly when you're looking to integrate Salesforce functionalities into non-Salesforce environments. Lightning Out enables the use of Lightning components, including flows, outside of Salesforce by allowing them to be embedded in any external web application. This is highly beneficial for providing users with a seamless experience as they interact with Salesforce data directly from an external app.

When a flow is embedded using Lightning Out, it retains the same look and feel as if it were running within Salesforce itself, while also allowing developers to fully leverage the UI capabilities of Lightning components. This strengthens the connection between the external application and Salesforce, maximizing functionality and user engagement.

While other methods such as API integrations and linking might seem plausible for accessing flows, they typically do not provide the same level of seamless integration as Lightning Out. API integration focuses more on data interchange and does not facilitate direct interactions with the flow's user interface. Linking to the flow or using Visualforce pages may also not offer the same user experience as leveraging the powerful components offered by Lightning Out.