Proton Mail vs Fastmail
Both are alternatives to Gmail. Here's how they stack up — verified facts, no spin.
Also searched as Fastmail vs Proton Mail — same comparison, one verdict.
Proton Mail is open source (GPL-3.0 (apps)) and Fastmail is not (Proprietary) — so the real question is whether you want to own the email & secure mail stack or rent it.
Proton Mail
TOP PICKEnd-to-end encrypted, open-source, Swiss — the privacy default.
Proton Mail is the most mature encrypted email provider, with over 100 million users and open-source apps on every platform. Mail is end-to-end and zero-access encrypted, it's based in Switzerland under strong privacy law, and it supports OpenPGP so mail with other PGP users is automatically end-to-end encrypted. It has grown into a genuine Gmail replacement with Calendar, Drive, Pass, and VPN in one account, plus a functional free tier.
Fastmail
Fast, reliable, standards-based mail — the productivity pick.
Fastmail is a long-running independent email host (Australian) built for speed, reliability, and standards support rather than encryption. It doesn't offer end-to-end encryption, but it doesn't scan your mail, sell your data, or show ads — you're the paying customer, not the product. Excellent custom-domain support, great apps, and best-in-class deliverability make it the honest pick when you want to leave Gmail for independence and quality without the constraints E2E encryption imposes.
Side by side
6 points of comparison, every one read from a verified field. Green marks the side that wins a row outright. A dash means we do not hold that fact — never that it is zero.
| Proton Mail | Fastmail | |
|---|---|---|
| Sovereignty ScoreOur transparent 0–100 composite for data ownership and exit cost. | 84 | 45 |
| Open source | Yes | No |
| Self-hostable | No | No |
| Local-first data | No | No |
| License | GPL-3.0 (apps) | Proprietary |
| Pricing | Free (1GB); paid Mail Plus ~$4/mo; bundled Proton Unlimited adds Drive, VPN, and Pass | From about $5/user/month; 30-day free trial; custom domains included |
Proton Mail is Macrostack's recommended Gmail alternative, so it's our pick here.
Weighing both against staying on Gmail? Is Gmail free? What it actually costs →
Proton Mail
Strengths
- +End-to-end, zero-access encryption with OpenPGP support
- +Open-source apps, independently audited, Swiss jurisdiction
- +Free tier; custom domains on paid plans
- +Part of a full privacy suite (Calendar, Drive, VPN, Pass)
Trade-offs
- −Encryption to non-Proton, non-PGP contacts needs password-protected mode
- −A hosted service you don't self-host
- −Free-tier storage is modest (1GB)
Fastmail
Strengths
- +Fast and reliable, with excellent IMAP/JMAP standards support
- +No ads and no data selling — you're the customer
- +Superb custom-domain and multi-identity handling
Trade-offs
- −No end-to-end encryption
- −Closed-source, commercial service
- −Australian jurisdiction (Five Eyes) may matter to some
Which one fits you
The trade-offs above, turned into a decision. Find the line that describes your team.
Choose Proton Mail
if you want the source and the option to fork it, and end-to-end, zero-access encryption with OpenPGP support.
Choose Fastmail
if fast and reliable, with excellent IMAP/JMAP standards support.
Neither, yet
if both carry a real cost you should weigh first — encryption to non-Proton, non-PGP contacts needs password-protected mode, and no end-to-end encryption. If either of those is a dealbreaker for your team, the shortlist is wrong rather than the choice.
Proton Mail vs Fastmail — common questions
Is Proton Mail a better fit than Fastmail for email & secure mail?
It depends on what you are optimising for, and the honest split is this: Proton Mail scores 84 to Fastmail's 45 on data ownership and exit cost, so it is the safer choice if you care about being able to leave. Fastmail earns its place on a different axis — fast and reliable, with excellent IMAP/JMAP standards support. Neither is a wrong answer for every team; the table above is the actual comparison.
What happens if we want to switch later?
Neither of these is local-first by default, so plan the exit at the point you adopt rather than later. Export what matters on a schedule instead of trusting you can retrieve it on demand — that is the most common way a email & secure mail migration turns into a project instead of an afternoon.
Are Proton Mail and Fastmail both alternatives to Gmail?
Yes — both appear in our Gmail comparison, which is why they are worth putting side by side. People usually arrive here already having decided to move off Gmail and now choosing between the two replacements, which is a narrower and much easier question.
Related alternative guides
Facts verified 2026-07-14. Licenses and pricing change — spotted something out of date? That's a correction we want.