Does Plain Have a Mobile App?

Plain does not have mobile apps for either iOS or Android, although they do have a responsive website which has a pretty decent mobile experience, so you can get away with bookmarking the Plain dashboard and responding on-the-go from any mobile browser.

Does Plain Have Multi-Inbox Support?

Plain does not allow for multiple inboxes. While you can connect multiple email addresses to Plain (like support@ + contact@ + billing@), it's not really advised to use it outside of support. You can have workflows to append a label and sort of split out emails into views that way, but it's just not the way that Plain was intended to be used.

Does Plain Have an API?

Plain does have an API, in-fact, they are an API-first help desk, which can be seen in their deep integrations with Slack, Linear, and Stripe, along with their detailed API docs, standing out in the help desk space which typically treats their API as an add-on feature versus a foundational feature.