How are you testing verification emails right now?

Building receivemail.dev (launching here today) because our own signup-flow tests kept either mocking the email step entirely or burning a real inbox for it.

Curious how others handle this: do you mock the verification email/code in tests, use a real mailbox with a filter, or something else? And if you've used a disposable-inbox API before (Mailosaur, Mailinator, etc.), what made you pick it?