You own your data. You can download a copy anytime, or delete your account entirely. Both live under Settings → Account.
Download your data
Settings → Account → Download a file. We send you a single file with all your clients, appointments, services, and settings. It's machine-readable so it's easy to import elsewhere.
Close your account
Settings → Account → Delete account. This is permanent. We delete everything: your account, services, clients, appointment history, and uploaded files. It can't be undone.
Before clicking Delete, download a copy of your data if you might want it later. Once it's gone, it's gone.
What about Stripe?
Your Stripe account stays — that's separate from Callisto. To close that too, log into stripe.com and close it there.