Proton Mail: What End-to-End Encryption Covers — and What It Doesn't
Proton Mail is the best-known encrypted email service, built around a simple structural promise: mail stored on its servers is encrypted in a way Proton itself cannot read, and decryption happens on your device. This page reads the published plans and documentation plainly — including the limits the homepage does not lead with.
Who Proton Mail fits
- Users uncomfortable with a readable mailbox sitting in a mainstream provider's custody — the at-rest encryption is the core product and it is real.
- Correspondents inside the same network — mail between Proton accounts is fully end-to-end encrypted with no extra steps, which is the product at its best.
- Privacy-bundle households — the higher plans bundle Proton's VPN, drive, and calendar under one subscription; the bundle is coherent because the components share an architecture, not just a checkout page.
What the plans include
The published structure has a free tier (limited storage and features, which is a genuine way to test the service), paid consumer tiers with more storage, custom domains and aliases, and business plans. Custom-domain support is the underrated feature: bringing your own domain means your address survives any future provider change — an exit hedge worth having in this category.
The cryptography is published: open-source apps, documented key hierarchy, and a long history of transparency reports. Jurisdiction, metadata minimization, and account-recovery semantics are all documented in the privacy policy — read those pages, not the homepage.
What stands out
- Honest limits documentation. The FAQ states plainly that mail to outside providers is only transport-protected and readable at the recipient's end — the candor this site keeps telling readers to look for.
- Password-protected external mail. Writing to non-Proton recipients securely is supported without requiring them to manage PGP keys — the realistic bridge for ordinary correspondents.
- Swiss incorporation with published transparency practice. Read the reports, not the folklore; the disclosures are the substance.
What to watch for
- The recipient-side gap. E2E applies within the network or via protected messages; ordinary outbound mail lands readable on the other provider's servers. Plan correspondence accordingly.
- Metadata. Content is encrypted; delivery metadata is minimized by policy rather than eliminated by physics. The policy documents what is kept — read it.
- Storage economics. Free-tier storage is small, and mailboxes grow. Price the paid tier you would actually need, not the one the marketing table starts at. [VERIFY current quotas and prices on the official site.]
Bottom line
Proton Mail is the conservative choice in encrypted email: documented cryptography, published audits and transparency practice, a real free tier, and the most honest limits documentation in its category. Adopt it for what it does — removing the provider's ability to read your mailbox — and with a clear view of what it cannot: encrypting the rest of the world's mail servers.
Check current Proton Mail plans →
This assessment is based on Proton Mail's published plan pages and documentation, current at the date above. Pricing and feature line-ups move often — confirm on the official site before you buy. The link above is a plain link to the vendor's official site; it does not change the assessment on this page.