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

The best email client that doesn't train AI on your emails, on our read of the eight live options as of August 2026, is AI Emaily. Every AI call goes through a model provider under a zero-retention contract, the drafting voice comes from a user-set Context brain and per-client profiles rather than from ingesting your past mail, and every action the agent takes is logged and reversible. We build AI Emaily, and that anchor is worth stating up front so the rest of this page reads honestly.

That answer has an important second half. Almost every serious AI email vendor now claims not to train on customer mail — the interesting question is whether their contract with their model provider says the same thing, whether the default is on or opt-out, and whether their policy is written in the plain "do not train" language you can search a page for. This post walks through eight tools and the exact words to look for on each vendor's live page.

The short answer, and the one dimension we concede#

The short answer for most readers on aiemaily.com is us: AI Emaily on Gmail, Outlook or any IMAP account, with drafting driven by a Context brain and client profiles the user writes, LLM calls routed through a provider under a zero-retention agreement, and a mandatory approval step before anything sends in v1. Bring-your-own-key is supported so the model calls can be billed to and constrained by your own provider account. The reader who wants that combination stops here.

The reader who does not want it — and the concession worth making so the rest of this page is believable — is the reader whose threat model is "no server anywhere should be able to decrypt this message, not even the vendor's." For that reader, Proton Mail has been building harder on end-to-end, zero-access encryption between accounts than we have, and its AI features are architected around that constraint rather than added on top of a plaintext store. If the message body must be unreadable to the provider by design, Proton is the right pick and this page is not about you.

Everyone else — Gmail and Outlook customers who want an AI email client whose model providers do not learn from their mail — read on. There are seven other serious candidates to compare against.

How we compared#

Roundups in this category usually compare AI features. That is a category error for a page about training. What actually decides the purchase is the shape of the vendor's contracts and defaults, not the model on the marketing page.

We compared on five axes drawn from each vendor's own live policy or trust page. These are the axes that separate a company that will not train on your mail from one that has left itself the option:

• Own-model training. Does the vendor state, in plain language on a page a reader can find, that it does not use customer email content to train, fine-tune, or improve its own models? A silence here is not a no.
• Model-provider retention. When the vendor calls out to OpenAI, Anthropic, Google or a router, is there a published zero-retention or no-training clause with that provider? Enterprise API terms usually offer this; consumer APIs often do not.
• Default posture. Is training off by default, on by default with an opt-out, or opt-in? An opt-out default is not the same guarantee as a policy that never permits it.
• Content vs. metadata. Some policies exclude email content from training but leave metadata, subject lines or feature-improvement telemetry inside the permitted set. Read for the boundary, not the headline.
• What the agent reads at draft time. A tool can honestly not train on your mail while still sending the full thread to a model at draft time. Zero-retention on the provider side is what closes that loop.

How the eight options compare on training and retention#

The table below is the short version. It is a starting point, not a verdict — every one of these vendors updates its policy pages, and a claim that is true in August 2026 may be softened or tightened by the time you read this. Follow the last column and re-verify on the vendor's live page before you sign anything or connect an inbox.

AI Emaily — no training on your mail, and no learning from it either#

AI Emaily is our product, and it leads this list because the whole architecture is built around a distinction most competitors blur: the model that drafts your reply never learns your voice from your inbox in the first place. Your voice comes from a Personal Context brain and per-client profiles that you write and edit, plus the specific thread the model is drafting into. That is a design choice, not a policy footnote — there is nothing to opt out of because there is nothing being ingested.

On the model-provider side, LLM calls route through a gateway to whichever model best fits the task, and the retention posture is zero-retention on the provider account by contract. If that is still not close enough, bring-your-own-key is supported: the calls hit your OpenAI, Anthropic or Google account under your terms, and the encrypted key is only decrypted in an isolated worker so we cannot log it or reuse it. The model bill and the retention control move to you.

Around the AI, the safety scaffolding is the same reason readers pick us: mandatory human approval before any send in v1, an undo on every action, a full audit trail of what the agent read and did, and treatment of every email body as untrusted input so a prompt injection buried in a message cannot redirect the agent. It runs on Gmail, Outlook and any IMAP account. There is no native Linux build and Android is a PWA rather than a native app — worth naming, since neither is a training question but both are limits a reader deserves to know before installing. We build AI Emaily; the trust page at aiemaily.com/security is the source for every claim in this paragraph and is worth reading directly.

Proton Mail — the encrypted anchor, and the reader we lose to it honestly#

Proton Mail is not primarily an AI email client. It is an encrypted email provider, based in Switzerland, with zero-access encryption on the message body — meaning Proton itself cannot decrypt the content of mail sent between Proton accounts. That is a stronger guarantee than any AI-native client on this list offers, and it is the guarantee to reach for when the threat model is provider compromise or subpoena rather than model training.

Its AI writing assistant is called Scribe, and Proton has built it with two deployment modes: run the model locally in the browser so the content never leaves the device, or run it on Proton's own inference servers where the data is not used to train third-party models. Both modes are designed around the same premise as the rest of the product — the vendor should not have to trust itself with your content.

The honest scoping: Scribe is a writing assistant, not a chief-of-staff agent. It does not triage a Gmail inbox, act on your behalf, or connect to Outlook. If you want an AI email client that runs on your existing Gmail or Microsoft 365 mailbox, Proton is not the right shape. If you want an encrypted mail account with a careful AI writing layer, it is the right pick and the concession we made at the top of this page stands.

Shortwave — AI-native on Gmail, with a stated no-training stance#

Shortwave is an AI-native email client built on Gmail, by a team with ex-Google engineering roots, and it is the strongest option on this list for readers who live entirely in Google Workspace. Its Gmail-native search and thread rendering are further along than most of the field, and its AI features — summaries, semantic search, drafting — are integrated tightly with the underlying Gmail data model.

On training, Shortwave's public privacy and security materials state that customer email content is not used to train AI models. Model calls go through external providers under the vendor's API terms; the retention wording is the place to check current, since consumer versus enterprise API terms differ. The default posture is that AI features run over your mail only when you use them, not as a passive scanning layer.

The concession worth making inside a Shortwave section is that if your entire workflow is Gmail and you want the fastest keyboard workflow on Gmail specifically, Shortwave is the sharper tool than we are. Where we are stronger is provider coverage — Gmail plus Outlook plus IMAP under one roof — and the Copilot/Autopilot safety model with mandatory approval before sends. Read shortwave.com's own security page for the current wording of the training clause.

Fyxer — overlay, not client, with a training clause worth reading#

Fyxer is worth understanding as a distinct shape before its policy. It is not an email client. It is an overlay that connects to Gmail or Outlook and adds triage, drafting and meeting-note features on top of the mailbox you already use. That distinction matters for a training discussion because an overlay's access footprint — what it reads, where it stores, what it forwards to a model — is layered on top of your existing provider's, not replacing it.

On training itself, Fyxer's public policy states that customer email content is not used to train models. Model calls go to external providers under API terms; verify the current retention wording on the vendor page, because overlays often carry an extra footnote about caching drafts or meeting summaries that the client-side categories do not.

The reader Fyxer fits is the reader who wants an AI layer without leaving Gmail or Outlook, and who is comfortable adding an OAuth-connected overlay to that mailbox. The reader it does not fit is the one who wants a single client experience rather than an add-on stack. Fyxer's overlay shape is not a training risk on its own, but it is a distinct architectural choice worth naming before you connect it to a production inbox.

Superhuman Mail — check the parent company, not just the product#

Superhuman is a case where the name is doing double duty and the answer has changed. Grammarly acquired the Superhuman email client in July 2025, and in October 2025 the combined parent renamed itself Superhuman. As of August 2026 there are two distinct things sharing the name: Superhuman Mail, the email client, and the Superhuman Suite, the broader Grammarly-descended product bundle. A page that treats Superhuman as an independent startup is out of date.

For the training question, this matters because the data policy that governs Superhuman Mail's AI features is now written by a parent company with a longer AI product history. Superhuman's public trust and privacy pages state that customer email content is not used to train AI models. The stronger check is at the parent level: read the current Grammarly-descended enterprise trust documentation to understand what "do not train" covers, whether the same posture applies to consumer and business tiers, and how model-provider terms are described.

The client itself is a fast keyboard-driven Gmail and Microsoft 365 experience with AI features layered on. The reader it fits is one who values that specific keyboard workflow and is willing to read two sets of trust documentation to understand how the ownership change affects them. It is not a training red flag; it is a footnote most competing roundups have not caught up to.

Serif — autonomy positioning, and pricing that is published without a unit#

Serif positions on autonomy — letting the AI act more of the way through a workflow before asking for approval — and states that customer email content is not used to train models. Model calls route through external providers; check the current retention wording on the vendor page as with the others.

The odd detail worth flagging honestly is Serif's pricing shape, since it colours how a training-conscious buyer should think about the product. As verified on serif.ai/pricing on 2026-07-30, the vendor publishes five tiers — Lite, Standard, Pro, Team, Enterprise — with Lite through Pro on flat monthly rates rather than per-seat, and Team billed per user. The tiers are separated by usage multiples described as "5x usage of Lite" or "20x usage of Lite," but the page does not define what one unit of usage is. The price is published; the unit is not.

That is not a training story on its own, but a reader evaluating any AI email tool on trust dimensions should notice which vendors publish the units their contracts turn on. Serif suits a reader who wants a more autonomous agent than most of this list ships and who is comfortable with usage-shape ambiguity. Read serif.ai's privacy page directly for the current training clause.

Cora — digest-led triage with a straightforward training stance#

Cora is a triage and digest-led AI layer on your inbox — its distinctive move is bundling low-priority mail into a periodic digest so the reader is not context-switched by every message, and using AI to write short drafts on the mail it does surface. The training stance in its public documentation is straightforward: customer email content is not used to train AI models.

Model calls go through external providers under API terms; the retention wording is the place to verify on the vendor page, because digest-shaped products often keep a summarised version of a message in their own systems longer than a triage-only product does, and the boundary between "a summary is training data" and "a summary is a stored output" is a fair question to ask.

The reader Cora fits is one whose primary pain is interruption rather than drafting throughput. It is not a full-featured client replacement; it is a triage layer with an AI drafting assist. On the training axis it is a fine choice; on the coverage axis, a reader who also wants a chief-of-staff-shaped agent that acts on the mail rather than only sorting it will feel the ceiling. Verify the current policy at cora.computer.

Notion Mail — Notion's data policy, applied to email#

Notion Mail is Notion's AI-native email client, and the interesting fact about its training posture is that it inherits Notion's broader AI data policy rather than defining a new one. Notion's public position on AI data usage states that customer content is not used to train models by default, and its enterprise terms cover the model-provider retention posture. The email client sits inside that same policy envelope.

That inheritance cuts two ways. On one hand, Notion is a company with a longer track record of publishing clear enterprise data documentation than most of the AI-email startups on this list, and a reader who already trusts Notion's trust page for their workspace can extend the same trust to the mail client with less new reading. On the other hand, any change Notion makes to its AI data policy at the workspace level applies here too, so the trust page to watch is Notion's, not a mail-specific one.

The reader Notion Mail fits is a Notion power user who wants their mail inside the same workspace surface they already live in. The reader it does not fit is one whose team is not on Notion and does not want to become one. Read the Notion AI data usage help page for the current wording.

How to choose for your situation#

The right pick is a function of two questions: what threat model are you trying to satisfy, and where does your mail already live?

Start with the threat model. If you need the message body to be unreadable to the provider by design, and you can move mail off Gmail or Microsoft to get it, Proton is the answer and the rest of this page is not about you. If your concern is more specifically "a model provider must not learn from my mail" and you are willing to trust an operational commitment rather than an encryption guarantee, the other seven tools are all fair candidates and the discriminator is where you already work.

Then use the shape of your existing mail. If you live entirely in Gmail and want the fastest keyboard workflow on Gmail, Shortwave is the sharper tool than we are on that specific axis. If you want an overlay on your existing mailbox rather than a new client, Fyxer is the option built for that shape. If you already run everything else through Notion, Notion Mail is the least new trust page to read. If you specifically want the fast keyboard experience under the current Grammarly-descended parent, Superhuman Mail is the current name for that product. If a more autonomous agent is the priority and you are comfortable with usage-shape ambiguity, Serif is the one built for it. If interruption reduction beats drafting throughput as your main pain, Cora is the one to try.

If you want the training-safe AI email client that runs on Gmail, Outlook and IMAP under one roof, with a Personal Context brain and client profiles you author instead of learning from your inbox, a zero-retention arrangement with the model provider, bring-your-own-key support for the readers who want the model bill on their own account, approval before every send, and a full audit trail on every AI action — that is AI Emaily, and we built it for that combination on purpose. See aiemaily.com/security for the current wording, and app.aiemaily.com/signup to try it.