Skiff Alternatives for End-to-End Encrypted Email

Skiff sold itself on cryptography, not chrome. If you chose it because your mailbox was end-to-end encrypted — not because the interface looked nice — then the replacement question is narrower than a generic "best private email" list. You are asking which Skiff alternatives for end-to-end encrypted email actually keep the same promise: that the provider in the middle cannot read your mail.

This roundup compares the providers on exactly that. Not the marketing word "encrypted," but what each one encrypts, what it cannot encrypt the moment you mail someone outside its walls, and where your metadata ends up sitting. We lead with the encrypted providers because that is the specific thing Skiff was — our own product, AI Emaily, does a different job and is covered plainly, with disclosure, further down.

The short answer: which providers replace Skiff#

For most former Skiff users, Proton Mail is the closest match. It gives you a zero-access, end-to-end encrypted mailbox with a surrounding suite — Calendar, Drive, and more — the same shape Skiff had, plus a free tier and an import tool. It is the least-compromise landing spot.

If you want the mailbox itself encrypted as tightly as possible, Tuta (formerly Tutanota) is the other strong pick. It encrypts more of each message than the others — including the subject line, which Proton and the OpenPGP providers leave readable. The trade-off is a leaner feature set and its own non-standard protocol.

After those two, Mailfence, StartMail, Posteo, and Mailbox.org cover people who valued open standards and OpenPGP over a proprietary zero-access model. They are private and standards-based, but their end-to-end guarantee is opt-in per message rather than automatic. Verify every plan and feature on the vendor's own page before you move — this cluster changes often.

What does end-to-end encryption actually mean for email?#

End-to-end encryption (E2EE) means a message is scrambled on your device and can only be unscrambled by the intended recipient. The provider passing it along holds only ciphertext. It never sees the readable message, so it cannot hand a plaintext copy to anyone — not an advertiser, not an attacker who breaches the server, not a subpoena.

The catch specific to email is that full E2EE needs a key at both ends. When you email another user of the same encrypted service, or someone whose OpenPGP public key you hold, the content is genuinely end-to-end encrypted. When you email a normal Gmail or Outlook address with no shared key, the content is not — unless you route it through a password-protected link, which we cover below.

There is also a second promise these providers make that is not the same as E2EE: zero-access, or zero-knowledge, storage. That means mail sitting in your mailbox is encrypted to a key the provider does not hold, so staff cannot read your stored inbox. It is a real protection, but it is about mail at rest, not about the message in flight to an outsider.

How we compared#

This is a capability comparison built from each vendor's own documentation, not a hands-on lab test — we did not re-run every provider's onboarding for this piece. Compare on documented, checkable dimensions, then re-verify on each vendor's page before you commit, because encryption details and plans move.

For someone leaving Skiff specifically over its encryption model, the dimensions that matter are narrower than a general privacy list:

• Encryption model — provider-managed zero-access or zero-knowledge (keys derive from your password) versus user-controlled OpenPGP versus standards-based mail with optional PGP on top.
• What actually gets encrypted — the message body only, or the body plus the subject line, and whether it is end-to-end or only encrypted at rest.
• Mailing a normal recipient — what happens when you send to a plain Gmail or Outlook address: TLS in transit only, a password-protected portal link, or OpenPGP if the recipient has a key.
• Metadata exposure — sender, recipient, and timestamp are always visible; the subject line is the swing factor between providers.
• Packaging shape — free tier, paid-only, or trial — described by shape, not price, because pricing changes and you should confirm it live.
• Platform and import — apps, standard IMAP compatibility, and whether you can import an archive you exported from Skiff before it closed.

Comparison table#

What the grid shows#

Two patterns stand out. First, only Tuta encrypts the subject line — every other option leaves it readable at the server boundary, because the OpenPGP standard treats subject lines as part of the header rather than the encrypted body. Second, the honest answer to "is my mail to an outsider end-to-end encrypted?" is "only if you take an extra step," for every provider here.

You will notice AI Emaily is not in this table. That is deliberate, and we build it, so we will say why directly: AI Emaily is not an encrypted email provider, so ranking it against Proton or Tuta on an encryption grid would be a category error. Where it does fit is its own section below.

Proton Mail — the closest thing to Skiff's whole suite#

Proton Mail is the natural home for most former Skiff users, because it matches the shape of what you lost. Mail in your inbox is protected with zero-access encryption, so Proton itself cannot read it, and the account comes with a surrounding ecosystem — Calendar, Drive, a password manager, a VPN, and documents — the same suite logic Skiff followed. It is open source and based in Switzerland.

For end-to-end encryption, Proton supports OpenPGP, so mail between Proton users, or to anyone whose public key you hold, is E2EE automatically. To reach a normal recipient with no key, you either send over TLS — encrypted in transit but readable by their provider — or use the Password-protected Emails feature, which delivers a link the recipient opens with a password you shared separately.

The one honest limit worth stating up front: Proton does not end-to-end encrypt subject lines, a choice it makes to stay interoperable with the OpenPGP standard. It keeps a free tier and an Easy Switch import tool for pulling mail across. Confirm current plans and the import path on Proton's own page before you migrate.

Tuta — the most-encrypted mailbox, including subject lines#

Tuta (renamed from Tutanota, and based in Germany) is the other true end-to-end encrypted replacement, and it encrypts more of each message than anything else here. By its own documentation it encrypts the body, attachments, and the subject line — the metadata most providers leave in the clear. That makes it the strongest pick if the subject line leaking bothers you.

The cost of that coverage is compatibility. Tuta uses its own encryption protocol rather than OpenPGP and does not speak standard IMAP, so you generally use it through Tuta's own apps rather than a third-party client, and importing works differently from a conventional provider. It does not support PGP at all, so there is no key-exchange path with outside PGP users.

To reach a normal recipient, Tuta uses a password-protected message: the recipient gets a notification and opens the encrypted mail after entering a shared password. Tuta also markets quantum-safe encryption (its TutaCrypt protocol combines x25519 and Kyber-1024). It keeps a free tier. Choose Tuta for maximum encryption with a lean feature set, and verify the current apps and plans on its site.

Mailfence — standards-based OpenPGP with key control#

Mailfence is the pick for people who want real OpenPGP rather than a proprietary encrypted client. It offers true end-to-end encryption using OpenPGP, performed in the browser, and lets you create, import, publish, and manage your own keys — so you hold the keys, not just the provider. It has run since 1999 and is based in Belgium.

Encryption here is selective and standards-based: you choose which messages to encrypt, and a message is end-to-end encrypted when the recipient also uses OpenPGP and you hold their public key. Mailfence also supports digital signatures, so a recipient can verify a message genuinely came from you. Mail to a recipient with no key travels as ordinary email, secured in transit but not end-to-end.

Because it is standards-based, Mailfence works with normal mail clients and makes importing an exported archive straightforward. It offers a free plan plus paid tiers. The trade-off versus Proton or Tuta is that the strong guarantee only applies when both sides use PGP — the burden of key exchange sits with you. Verify the current plans on Mailfence's own page.

StartMail — OpenPGP plus disposable aliases#

StartMail, from the team behind the Startpage search engine and based in the Netherlands, is another OpenPGP-based option. It supports PGP encryption and can do end-to-end encryption over IMAP with a compatible client, so it fits people who want a standard mail client rather than a walled app. Being in the Netherlands, it sits under the EU's GDPR.

Its distinctive feature is aliases: unlimited custom aliases plus one-click burner addresses that expire automatically, which is useful for keeping your real address off signup forms. That is a different privacy angle from Skiff's — it limits who ever learns your address, on top of encrypting content.

To email someone without encryption set up, StartMail lets you set a password so the recipient can open and reply to an encrypted message. As with the other OpenPGP providers, full end-to-end encryption applies when both sides use PGP. StartMail is a paid service that offers a 7-day free trial rather than a permanent free tier. Confirm the current trial and plans on its site.

Posteo and Mailbox.org — German standards-based privacy#

If you want privacy grounded in open standards and a strong European jurisdiction rather than a proprietary zero-access model, two Berlin-based German providers stand out. Both put servers in Germany so German data-protection law and the EU's GDPR apply, and both are built on standard IMAP and SMTP, so any mail client works and importing a Skiff export is straightforward.

Posteo is the minimalist, sustainability-minded choice: paid-only with no free tier, powered by green energy, and built around data minimisation, including anonymous signup and payment. It supports inbound encryption with PGP or S/MIME and offers an optional crypto mail store that encrypts your whole mailbox at rest with a password. It is not zero-access end-to-end encrypted by default, so weigh that if cryptographic secrecy is the hard line.

Mailbox.org pairs a standards-based mailbox with its Guard feature — PGP in the webmail client, no extra software — plus S/MIME support and, on request, encrypting previously received mail with your own PGP key. It also bundles calendar and cloud storage, a suite-shaped option for people who prefer PGP and interoperability to a closed encrypted client. Verify current plans, trials, and features on each provider's page.

Where AI Emaily fits — and where it does not#

One disclosure first: we build AI Emaily, so read this as us being straight about a boundary, not nominating ourselves as a Skiff replacement. AI Emaily is not an encrypted email provider. It does not host mailboxes, and it is not a zero-access or zero-knowledge, end-to-end encrypted service like Skiff, Proton, or Tuta. If a private encrypted mailbox is what you need, pick one of those, not us.

What AI Emaily is: an AI email client that sits on top of an existing mailbox — Gmail, Outlook, or any IMAP account, including Proton by way of its Bridge — and adds triage, drafting in a voice you configure through a Context brain and per-client profiles, and an approval-first agent that never sends without you. It is the layer you would add after you have chosen where your mail lives, not the place it lives.

There is an honest tension worth naming, and it is exactly why we are not on the encrypted-provider list. An AI assistant has to read your mail to summarise, triage, and draft on it, which is fundamentally at odds with a zero-access model where only you can read anything. AI Emaily reflects that by not training any model on your mail and gating every action behind your approval, with undo and an audit trail — but it is still software reading your messages, not zero-access encryption. Moving to Proton or Tuta for cryptographic privacy is one decision; adding AI on top is a separate one.

Can encrypted email work with normal recipients?#

Yes, but you have to know which of three things is actually happening, because only two of them are end-to-end encrypted. This is the question most "private email" marketing quietly skips.

First, plain delivery over TLS. The message is encrypted in transit between mail servers, but the recipient's provider receives it in readable form and can read or scan it. This is the default when you email a normal address, and it is not end-to-end encryption. Second, a password-protected link — Proton's Password-protected Emails, Tuta's external messages, StartMail's password option — where the recipient opens the mail in a secure portal using a secret you shared separately. That is effectively end-to-end, as long as you deliver the password over a different channel.

Third, OpenPGP. If your recipient uses PGP and you hold their public key, mail is end-to-end encrypted automatically with no portal — the approach Proton, Mailfence, StartMail, and Mailbox.org support. The practical takeaway: encrypted email works with anyone, but with a normal recipient the strong guarantee needs a deliberate step every time, and the subject line and the fact of the message still travel in the open.

Where the metadata sits#

The angle Skiff refugees care about most is metadata, because content encryption is the easy part and metadata is where the differences hide. Three layers are worth separating.

The envelope — sender address, recipient address, and timestamps — is visible to the providers on both ends, for every option on this list, because mail cannot be routed without it. No consumer email provider hides this, and any that claims to should be read very carefully. The subject line is the layer that actually differs: Tuta encrypts it; Proton, Mailfence, StartMail, and Mailbox.org do not, because OpenPGP-style encryption protects the body and leaves the subject in the header.

Stored mail is the third layer. Zero-access and zero-knowledge providers (Proton, Tuta) encrypt your inbox at rest so their own staff cannot read it; Posteo offers optional whole-mailbox encryption at rest; standards-based mail without PGP is readable by the provider on their servers. So the honest ranking on metadata is: Tuta hides the most, Proton hides the stored content but not the subject, and the OpenPGP providers protect the body you choose to encrypt while leaving subjects and the envelope exposed. These details are documented on each vendor's security pages — check them, since they are exactly the claims that get revised.

How to choose for your situation#

The right move depends on which part of Skiff's encryption you will actually miss. Match your situation to one of these and you have your answer.

1. 1

   You want zero-access encryption and the full suite

   Go to Proton Mail. It is the closest structural match to Skiff — an encrypted mailbox plus Calendar, Drive, and more — with a free tier and an import tool. Accept that subject lines are not end-to-end encrypted.

2. 2

   You want the most-encrypted mailbox, subjects included

   Choose Tuta. It encrypts the body, attachments, and the subject line, at the cost of standard-protocol compatibility and a leaner feature set. No PGP.

3. 3

   You want open standards and to control your own keys

   Choose Mailfence or StartMail for user-managed OpenPGP that works with normal clients. StartMail adds disposable aliases; both need the recipient on PGP for full end-to-end encryption.

4. 4

   You want a minimal, low-cost, jurisdiction-strong mailbox

   Choose Posteo (anonymous, green, no domains) or Mailbox.org (PGP Guard plus a broader suite). Neither is zero-access by default, so skip them if that is your hard requirement.

5. 5

   You have already moved and want AI on top

   Add AI Emaily to your new Gmail, Outlook, or IMAP inbox for triage and approval-first drafting. We build it, and it is a client layer, not an encrypted mailbox.