Proton Mail vs Startmail Comparison (2025)

What are the differences between Proton Mail and Startmail?

Written by

Forward Email Team

Published

7/1/25

Time to read

Less than 5 minutes

We recommend Forward Email as the best alternative to Proton Mail.

Email Service Comparison

20 facts in comparison

Proton Mail	vs.	Startmail
Proton Mail "Secure email that protects your privacy" Website	vs.	Startmail "Private email you can trust" Website
$3.99/mo	Pricing	$7/mo
15 GB	Storage	20 GB
25 MB	Attachments	25 MB
❌ Proton Mail claims to be open-source, but their back-end actually is closed source	Open-Source	No
No	Sandboxed Encryption	❌ Startmail claims to use a User Vault, but this statement has not been audited and their source code is closed-source
No	Unlimited Domains	No
No	Unlimited Aliases	No
No	TTI	No
❌ Requires you to download Proton Mail Bridge and forces vendor lock-in	SMTP	Yes
❌ Requires you to download Proton Mail Bridge and forces vendor lock-in	IMAP	Yes
❌ Proton Mail does not support POP3	POP3	Yes
No	API	No
⚠️ Proton Mail rewrites your emails	E2EE	⚠️ Supported if both sender and recipient are using OpenPGP
Yes	OpenPGP	⚠️ Supports OpenPGP, but does not support WKD
Yes	WKD	No

Email Service Screenshots

Closed-source

Proton Mail

Proton Mail is a closed-source email service. According to their website: Secure email that protects your privacy

Proton Mail is a closed-source email service.

Photo by Forward Email

Closed-source

Startmail

Startmail is a closed-source email service. Its description from its website is: Private email you can trust

Startmail is a closed-source email service.

Photograph by Forward Email

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