Proton Mail vs Tuta for Business: Encrypted Email Compared

Proton Mail and Tuta (formerly Tutanota) are the two names that come up when a company wants end-to-end encrypted email on its own domain. Both are European, both encrypt mailboxes so the provider cannot read them, and both ask you to give up some convenience in return. Which one fits a business depends on how much you rely on standard mail clients and what you need beyond email.

Quick answer

Proton is the better fit for most businesses: a bigger ecosystem (Calendar, Drive, VPN, Pass), a desktop bridge that makes IMAP clients work, and more admin tooling. Tuta is the purer privacy choice: it encrypts more of the message, including subject lines, at the cost of no IMAP at all and a smaller feature set. Both are paid per user per month for custom domains; the free personal tiers do not include your domain.

Feature comparison

• Mailboxes: both sell per-user business plans; each user gets a fully encrypted mailbox
• Free plan: both have a free personal plan, but custom domains require a paid plan on both
• API: neither offers a public transactional sending API; automation is done through SMTP submission on Proton business plans or not at all on Tuta
• DNS guidance: both show MX, SPF, DKIM and DMARC values and verify them in the admin area; Proton's wizard is more detailed
• IMAP/SMTP: Proton supports standard clients through Proton Bridge on paid plans; Tuta has no IMAP or SMTP client access and relies on its own apps
• Storage: both allocate per-user storage that grows with plan tier; Proton pools it across Mail and Drive

Where Proton Mail wins

• Proton Bridge lets Outlook, Apple Mail and Thunderbird work with the encrypted mailbox
• Calendar, Drive, VPN and password manager under one subscription reduce vendor sprawl
• Business admin features such as organisation keys, user roles and data recovery are more developed
• Larger user base and more third-party integrations, including SMTP submission for automated mail

Where Tuta wins

• Subject lines and calendar entries are encrypted too, not just message bodies
• Post-quantum cryptography was added early and the whole client is open source
• Simpler pricing with fewer add-ons to understand
• Servers and company are in Germany, which some customers or regulators prefer

Total cost at 5 and 15 users

Both are paid per user per month with custom domains available only on business tiers. At 5 users you are looking at a modest monthly subscription on either; at 15 users the bill is meaningful and Proton's higher tiers cost more than Tuta's. The bigger cost is workflow: Tuta means no standard mail client for anyone, and Proton means installing Bridge on every desktop that wants Outlook or Apple Mail.

The free third option: OquMail

If you do not need end-to-end encrypted mailboxes but you do need professional addresses that work in any client, OquMail is the free option. Transport is encrypted with TLS on IMAP 993 and SMTP 587 like any modern host, and there is no bridge or special app required. It is the right pick when the goal is credibility and reachability rather than zero-knowledge storage.

• Free plan: up to 15 mailboxes, 3 domains, 5 GB per mailbox, no credit card
• Webmail included; IMAP/SMTP for Outlook, Apple Mail, Thunderbird and phones
• IMAP mail.oqumail.com port 993 (SSL/TLS); SMTP mail.oqumail.com port 587 (STARTTLS)
• Guided SPF, DKIM and DMARC with live DNS verification; MX is mail.oqumail.com priority 10
• Transactional send API at https://api.oqumail.com/api/v1/emails with Bearer API keys (from, to, subject, html)
• Per-message delivery logs so you can see the exact response a receiving server gave

Verdict by scenario

• Law firm, journalist or NGO that must keep message contents unreadable by the host: Proton, for the balance of privacy and usability
• Team that wants maximum encryption and is happy to live in one app: Tuta
• Company that just needs branded inboxes, Outlook support and an API: OquMail
• Mixed need: put sensitive roles on Proton and everyone else on a free host using a subdomain of the same brand

Common questions

Can I use Outlook with Tuta?

No. Tuta has no IMAP or SMTP access; you use the Tuta web, desktop and mobile apps. Proton supports Outlook through Proton Bridge on paid plans.

Are Proton and Tuta emails encrypted to outside recipients?

Only when you use their password-protected message feature or the recipient uses PGP. Normal mail to a Gmail user is encrypted in transit with TLS, the same as any provider.

Can I send automated emails from my app with either?

Proton allows SMTP submission on business plans for low-volume system mail. Tuta does not. For receipts and notifications, a send API such as the one included with OquMail is simpler and gives delivery logs.