Best Email Client That Doesn't Train AI on Your Email

Short answer: the email clients that state they do not train AI on your mail include AI Emaily (our product), Proton Mail’s Scribe assistant, Shortwave, Superhuman Mail, Serif and Cora. The promises are not identical, so read each vendor’s own wording. If you want email without AI at all, that is a different choice: pick a provider with no AI features, such as Tuta or Fastmail.

Searchers land here with two different questions, and the answers do not overlap much. Here is the split before anything else.

The short answer, and the one dimension we concede#

We build AI Emaily, so weigh this accordingly. For readers who want AI help on Gmail, Outlook, iCloud or an IMAP account without their mail training anyone’s model, it is our pick: drafting follows a Personal Context and client profiles you write yourself, our security page states that cloud model calls run under zero-data-retention terms, and you choose how far the AI goes, from Manual to Copilot (you approve every send) to Autopilot within your own rules.

The concession: if your threat model is that no server, including the vendor’s, should be able to decrypt a message, Proton Mail has built far harder on end-to-end, zero-access encryption than we have, and its Scribe assistant is designed around that constraint. If the message body must be unreadable to the provider by design, Proton is the right pick.

How we compared#

Most roundups compare AI features. For a page about training, what decides the purchase is the vendor’s contracts and defaults. We read each vendor’s own live privacy, security or help pages in October 2026 and compared on four questions.

• Own-model training: does the vendor say plainly that your mail is not used to train, fine-tune or improve its own models, or only that third-party providers will not train on it? Those are different promises.
• Model-provider retention: when the vendor calls an outside model, does it say the provider keeps nothing (zero data retention)?
• Defaults: is any training off by default, or on with an opt-out you have to find?
• Per-user learning: does the tool study your past mail to imitate your style? That is not training a shared model, but it is your mail being read and kept in some form.

How the options compare on training and retention#

Last verified: October 2026, against each vendor’s own pages. Policies change, so re-check the linked page before you connect an inbox.

Does AI Emaily train on your email?#

No. Our security page says your email, calendar and contacts are never used to train, fine-tune or improve any AI model, ours or a provider’s, and that cloud inference runs under zero-data-retention terms. The drafting voice does not come from mining your inbox: it comes from a Personal Context and per-client profiles you write and edit, plus the thread being answered. There is nothing to opt out of because nothing is being collected for training.

If you want the model bill and retention terms on your own account, the Autopilot plan supports bring-your-own-key with an Anthropic, OpenAI or Google key, decrypted only in an isolated worker and never logged. Around the AI, every email body is treated as untrusted input to resist prompt injection, Copilot requires your approval before any send, and Autopilot actions come with undo and an audit log.

The limits: an AI client has to read a message to help with it, so this is “no training”, not “no AI”. It runs on the web, macOS, Windows and iOS; Android is coming. There is no free plan, but Pro and Autopilot have a 7-day free trial.

Does Proton Mail’s AI train on your email?#

Proton Mail is an encrypted email provider first, with zero-access encryption so Proton cannot read stored message bodies. Its AI writing assistant, Scribe, can run in two ways: download a model and run it on your device, so drafts stay local until you send, or run on Proton’s servers, where Proton says prompts are encrypted in transit and deleted after use. Its privacy policy says Scribe does not use your data to train its models.

The scoping: Scribe is a writing assistant for composing inside Proton. It does not triage a Gmail or Outlook inbox or act on your behalf. If you want an encrypted mailbox with a careful AI writing layer, it is the right pick; if you want AI on the Gmail or Microsoft 365 mailbox you already have, it is the wrong shape.

Does Shortwave train on your email?#

Shortwave is an AI email client built on Gmail and the strongest option here for people who live entirely in Google Workspace. Its security guide says your email content is never used to train third-party AI models, names its sub-processors (Google Cloud, OpenAI, Anthropic and Pinecone), and says the vast majority of its AI workloads run on open-source models on hardware it controls.

What the page does not say is whether Shortwave trains its own models on your mail, so that is the question to ask before connecting a sensitive inbox. Our concession: if your whole workflow is Gmail and you want the sharpest Gmail-native search and keyboard flow, Shortwave is further along there than we are. We are broader on providers, with Outlook, iCloud and IMAP in one inbox.

Does Fyxer train on your email?#

Yes, in one specific sense, and this is the correction most roundups miss. Fyxer’s security documentation says it never lets other AI providers train their general models on your data, but it also says Fyxer trains its own models to improve drafting, inbox sorting and transcription. You can switch that off in Dashboard settings, and admins can opt out for a whole organisation. On the Enterprise plan the opt-out is on by default; the page does not state the default for other plans, so check yours.

Fyxer also learns each user’s writing style and preferences to draft in their voice, which keeps working even if you opt out of training. Fyxer is an assistant layered on your existing Gmail or Outlook rather than a separate client, which suits people who do not want to change apps. If “my mail never improves anyone’s model” is your requirement, make sure the training opt-out is set before you connect it. Our guide to AI overlays versus native clients covers the wider trade.

Does Superhuman Mail train on your email?#

Superhuman changed hands: Grammarly acquired the Superhuman email client in July 2025, and on October 29, 2025 the parent company renamed itself Superhuman, keeping Grammarly as a product. Superhuman Mail is the email client inside that suite, and superhuman.com/privacy now redirects to the Grammarly privacy policy, which is the one that governs it.

Superhuman’s help center says neither Superhuman nor any vendor trains on your data, and it describes a zero-data-retention agreement with OpenAI. The nuance is storage: some AI features keep queries and responses for a period to improve quality, so read the current AI overview for which features and how long. The client fits people who want a fast keyboard-driven Gmail and Microsoft 365 experience.

Does Serif train on your email?#

Serif positions on autonomy, letting the assistant handle more of a reply before asking you. Its security page says your emails are never used to train general AI models, that emails are never stored on its servers, and that everything the assistant learns is encrypted at rest and private only to you.

The word to notice is “general”: the promise covers shared models, and the assistant does learn something about you. That is a reasonable design, but it is not the same as an assistant that learns nothing from your mail. Read the security page for the current wording.

Does Cora train on your email?#

Cora is an AI layer for Gmail that bundles low-priority mail into a daily brief and drafts replies to what it surfaces. Its homepage says it never trains on your data and that it sends email to model providers only to run the service.

Its privacy policy is narrower and worth reading. It reserves the right to use content to train Cora’s own models in general, then states that neither Cora nor its third-party AI providers will use your Google Data, meaning your Gmail, to train their models, and that Google Data is handled with zero data retention. For a Gmail-only product that covers the mailbox, but the contract wording, not the homepage, is the commitment.

Want email with no AI at all? Email without AI, and what to use instead#

If you searched for email that doesn’t use AI, the honest answer is not an AI client, ours included. No AI email means a mailbox where no model reads your messages because there are no AI features. A few providers say so plainly, and if you are staying on Gmail, see turning off Gmail’s AI-based smart features.

• Tuta: has said it will not add cloud-based AI to its encrypted email client, and encrypts mail end to end. It has no IMAP, so only Tuta’s own apps can open the mailbox.
• Fastmail: says it has not integrated AI into the inbox and has never trained AI on customer data. It offers an optional MCP server, but only if you choose to connect an outside AI tool yourself.
• Posteo: its feature list includes no AI tools and its support is answered by people, not bots, though we did not find a formal no-AI pledge on its site.
• Already on Gmail? Turning off smart features in Gmail’s settings stops Smart Compose, Smart Reply and AI summaries, and there is a separate Google Workspace smart features switch.
• On iPhone, Apple’s guide lists per-feature switches for Apple Intelligence; for Mail, turn off Summarize Message Previews in Settings, Apps, Mail. Labels can differ between iOS 27 and iOS 26.

How to choose for your situation#

Start with the threat model. If the provider must be unable to read your mail, choose Proton (with Scribe if you want AI writing help) or Tuta (with no AI). If your concern is that nobody’s model learns from your mail, any of the AI tools above can work once you have read its wording, and the deciding factor is where your mail lives.

Then match the shape. Gmail only, and you want the fastest Gmail workflow: Shortwave. An assistant layered on Gmail or Outlook without changing apps: Fyxer, with the training opt-out set. A fast keyboard client under the Grammarly-descended parent: Superhuman Mail. A more autonomous assistant: Serif. Interruptions are the main pain: Cora.

If you want one client across Gmail, Outlook, iCloud and IMAP, with a voice you set yourself, no training on your mail, zero-data-retention model calls, bring-your-own-key on Autopilot, and approval or audit on every action, that is the combination we built AI Emaily for. Our guide to whether AI tools train on your emails covers the policy language in more depth.