When we're building software, we feel it's crucial to let our clients and end users play around with the real software as it's in development. When it comes to email, we wanted 2 things:

• to make it impossible for clients to accidentally email real people in the preview/uat environment; and
• to make testing email based functionality really simple, by showing the emails inside the app they're testing, without them needing an account for some 3rd party tool.

Imitate Email, with its embeddable email viewer, sandbox mail server and login-less auth achieves all those things.