Privacy Policy

Last updated October 24, 2026

Mailstack is operated by Clutchclick ("we"). This policy explains what we collect when you use Mailstack, and what we do with the data our customers send through it.

Two kinds of data

Customer data is what you, a Mailstack customer, put in: your account details, your sending domains, your contacts, and your emails. Subscriber data is the information about the people you email, which you control. We process subscriber data only to provide Mailstack to you, as your processor.

What we collect

• Your email address and name, to sign you in. If you set a password, we store only a one-way hash of it, and if you turn on two-factor authentication, the key for your authenticator app.
• If you sign in with Google, your name, email address and profile picture from your Google account. We ask for nothing else from Google.
• The contacts, lists, campaigns and emails you create, and their delivery events: sent, delivered, bounced, complained and unsubscribed.
• Opens and clicks of newsletter emails: each carries a small image and links that pass through Mailstack, so the sender sees which emails were opened and which links were clicked. Subscribers' mail apps can block the image.
• When a subscriber signs up through a Mailstack form, the time and IP address of their consent, so you can show they asked.
• Basic request logs (IP address, user agent, time) to keep the service secure and working.

How we use it

To send the email you ask us to send, to show you what happened to it, to enforce our anti-spam rules (suppressing bounced and complaining addresses, pausing senders with high bounce or complaint rates), and to keep Mailstack secure. We don't sell data, and we don't use subscriber data for advertising.

Google user data

We use the information we receive from Google only to create your Mailstack account and sign you in. We don't share it, sell it, or use it for advertising. Mailstack's use of information received from Google APIs adheres to the Google API Services User Data Policy, including the Limited Use requirements. You can disconnect Mailstack from your Google account at any time in your Google account settings.

Who processes it

Mailstack runs on Cloudflare (hosting and storage) and sends through Amazon Web Services (Amazon SES). They process data on our behalf to run the service.

Subscribers

If you got an email sent with Mailstack, the sender who emailed you controls your data. Every newsletter has an unsubscribe link that works with one click. To have your data removed, ask the sender, or write to us and we'll help.

Retention and deletion

We keep customer data while your account is open. You can delete contacts at any time, and when you close your account we delete your data, except addresses kept on suppression lists so that people who bounced or complained are never emailed again.

Contact

Questions or requests: hello@mailstack.ai.