Proton Mail alternatives: 6 apps ranked by verified data

Facts checked Oct 25, 2026AppBreakup editorialHow we rank

Common reasons people leave Proton Mail: free plan has little storage and one address, and search and third-party integrations are more limited than Gmail. We ranked 6 alternatives by how directly each one replaces Proton Mail, then by reviews, real visits and how recently each app's facts were checked against its own website. Tuta currently ranks first.

Quick comparison

#	App	Pricing	Open source	Platforms	Verified facts	Score
1	Tuta	Free plan + paid	Yes	Web, Windows, macOS +3	4 of 4	66.5
2	Fastmail	Paid	No	Web, iOS, Android	5 of 5	62.6
3	mailbox.org	Paid	No	Web	4 of 4	59.6
4	StartMail	Paid	No	Web, iOS, Android	4 of 4	57.2
5	Posteo	Paid	No	Web	4 of 4	55.3
6	Mailfence	Free plan + paid	No	Web	3 of 3	53.6

1. TutaTop pick
Best for: People who want the most encryption for the least money and accept using Tuta's own apps
Free plan + paidOpen sourceWeb, Windows, macOS, Linux, iOS, Android
66.5
score / 100
Why switch from Proton Mail
Encrypts more of the mailbox, including subject lines and calendar, at a lower price.
Pros
Encrypts subjects, contacts and calendars, not just bodies
Open-source apps on desktop, mobile and web
Low-cost paid plans with custom domains
Cons
No IMAP, so third-party mail apps are not supported
Search and filtering are basic
Free plan has very little storage
Visit Tuta Compare with Proton Mail Details and reviews
How this score is calculated
Editorial fit ×0.3100
Reviews ×0.363
Clicks (90 days) ×0.150
Freshness ×0.1585
Votes ×0.150
0 counted reviews, 0 up and 0 down votes. Full formula
Is Tuta a good Proton Mail alternative?
Verified facts
4 of 4 verified
Storage (Free / Revolutionary / Legend)
1 GB / 20 GB / 500 GB
Checked Oct 25, 2026tuta.com(opens source in a new tab)
Encryption
End-to-end, post-quantum
Checked Oct 25, 2026tuta.com(opens source in a new tab)
Family member add-on
€3 per user/month (Revolutionary)
Checked Oct 25, 2026tuta.com(opens source in a new tab)
License
GPL-3.0
Checked Oct 25, 2026github.com(opens source in a new tab)
2. Fastmail
Best for: People and families who want private, ad-free email on their own domain
PaidWeb, iOS, Android
62.6
score / 100
Why switch from Proton Mail
Not end-to-end encrypted, but faster search, better calendars and standard IMAP access.
Pros
Fast web app with excellent search
Masked Email aliases and easy custom domains
Standard IMAP, CalDAV and JMAP support for any client
Cons
No free plan
Not end-to-end encrypted
No desktop apps of its own
Visit Fastmail Details and reviews
How this score is calculated
Editorial fit ×0.387
Reviews ×0.363
Clicks (90 days) ×0.150
Freshness ×0.1585
Votes ×0.150
0 counted reviews, 0 up and 0 down votes. Full formula
Is Fastmail a good Proton Mail alternative?
Verified facts
5 of 5 verified
Free trial
30 days
Checked Oct 25, 2026fastmail.com(opens source in a new tab)
Founded
1999
Checked Oct 25, 2026fastmail.com(opens source in a new tab)
Headquarters
Melbourne, Australia
Checked Oct 25, 2026fastmail.com(opens source in a new tab)
Masked Email
Yes
Checked Oct 25, 2026fastmail.com(opens source in a new tab)
Data location
EU or USA
Checked Oct 25, 2026fastmail.com(opens source in a new tab)
3. mailbox.org
Best for: European individuals and businesses who want private email and office tools in one place
PaidWeb
59.6
score / 100
Why switch from Proton Mail
German provider with PGP support and an office suite, priced per user.
Pros
Low per-user prices with custom domains
Data stored in Germany with PGP options
Includes calendar, cloud storage, office suite and meetings
Cons
Web interface feels dated
No dedicated mobile apps
No free plan
Visit mailbox.org Details and reviews
How this score is calculated
Editorial fit ×0.377
Reviews ×0.363
Clicks (90 days) ×0.150
Freshness ×0.1585
Votes ×0.150
0 counted reviews, 0 up and 0 down votes. Full formula
Is mailbox.org a good Proton Mail alternative?
Verified facts
4 of 4 verified
Light plan
€1 per user/month (2 GB)
Checked Oct 25, 2026mailbox.org(opens source in a new tab)
Standard plan
€4 per user/month (20 GB)
Checked Oct 25, 2026mailbox.org(opens source in a new tab)
Free trial
30 days
Checked Oct 25, 2026mailbox.org(opens source in a new tab)
Data location
Germany
Checked Oct 25, 2026mailbox.org(opens source in a new tab)
4. StartMail
Best for: People who want private email with lots of aliases and simple encryption
PaidWeb, iOS, Android
57.2
score / 100
Why switch from Proton Mail
Dutch private email with unlimited aliases and works with any IMAP client.
Pros
Unlimited aliases on all plans
Password-protected encrypted email to anyone
IMAP support for any mail app
Cons
No free plan
Fewer features and add-on services than Proton
Stored mail not end-to-end encrypted by default
Visit StartMail Details and reviews
How this score is calculated
Editorial fit ×0.369
Reviews ×0.363
Clicks (90 days) ×0.150
Freshness ×0.1585
Votes ×0.150
0 counted reviews, 0 up and 0 down votes. Full formula
Is StartMail a good Proton Mail alternative?
Verified facts
4 of 4 verified
Personal plan
$59.88 per year
Checked Oct 25, 2026startmail.com(opens source in a new tab)
Free trial
7 days
Checked Oct 25, 2026startmail.com(opens source in a new tab)
Aliases
Unlimited
Checked Oct 25, 2026startmail.com(opens source in a new tab)
Jurisdiction
Netherlands
Checked Oct 25, 2026startmail.com(opens source in a new tab)
5. Posteo
Best for: People who want cheap, private email that works with any standard mail app
PaidWeb
55.3
score / 100
Why switch from Proton Mail
A low-cost, anonymous-signup provider in Germany with standard IMAP access.
Pros
Very low fixed price with no ads
Anonymous sign-up and payment
Standard protocols, so any mail and calendar app works
Cons
No custom domains
Plain web interface and no own mobile apps
No free plan
Visit Posteo Details and reviews
How this score is calculated
Editorial fit ×0.363
Reviews ×0.363
Clicks (90 days) ×0.150
Freshness ×0.1585
Votes ×0.150
0 counted reviews, 0 up and 0 down votes. Full formula
Is Posteo a good Proton Mail alternative?
Verified facts
4 of 4 verified
Price
1 EUR per month
Checked Oct 25, 2026posteo.de(opens source in a new tab)
Storage
4 GB, upgradeable
Checked Oct 25, 2026posteo.de(opens source in a new tab)
Anonymous sign-up
Yes
Checked Oct 25, 2026posteo.de(opens source in a new tab)
Included apps
Email, address book, calendar, notes
Checked Oct 25, 2026posteo.de(opens source in a new tab)
6. Mailfence
Best for: Users who want OpenPGP encryption that works with other PGP tools
Free plan + paidWeb
53.6
score / 100
Why switch from Proton Mail
Belgian encrypted email with OpenPGP keys you control and a free plan.
Pros
OpenPGP encryption and signatures built in
Works with standard mail clients via IMAP and POP
Includes calendar, contacts and documents
Cons
PGP key management has a learning curve
Plain, utilitarian interface
Free plan is small
Visit Mailfence Details and reviews
How this score is calculated
Editorial fit ×0.357
Reviews ×0.363
Clicks (90 days) ×0.150
Freshness ×0.1585
Votes ×0.150
0 counted reviews, 0 up and 0 down votes. Full formula
Is Mailfence a good Proton Mail alternative?
Verified facts
3 of 3 verified
Free plan
1 GB
Checked Oct 25, 2026mailfence.com(opens source in a new tab)
Jurisdiction
Belgium
Checked Oct 25, 2026mailfence.com(opens source in a new tab)
Encryption
OpenPGP
Checked Oct 25, 2026mailfence.com(opens source in a new tab)