Best AI Auto-Reply Tools for Gmail and Outlook (2026)

Yes, AI can reply to your emails automatically, but most AI auto-reply tools for Gmail and Outlook do not send anything: they write a draft and wait for you. Only a few send on their own, and the controls around that send (who it may answer, how long you have to cancel, what gets logged) matter more than drafting quality.

One disclosure first: we build AI Emaily, and it is our top pick. That is why its section is longest, why its limits are stated in full, and why one competitor here beats us outright on the exact dimension this post is about.

Can AI reply to Outlook messages automatically?#

Yes, through four routes, and they behave very differently. Outlook's own automatic replies send fixed text you wrote. Microsoft Copilot in Outlook drafts a reply, and you press send. An automation flow that wires a new-mail trigger to an AI model can send with nobody reviewing it, and AI email clients and add-ins sit in between: most draft, a few send inside rules you set.

That is the whole map for anyone searching for an AI autoresponder or an AI auto reply for Outlook. The table below shows where each route lands on the question that matters, which is whether a person reads the reply before the recipient does.

Which AI auto-reply tools send on their own, and which wait for you?#

The category name covers three mechanisms. A fixed autoresponder can only repeat text you wrote. An AI draft cannot reach anyone until you press send. An autonomous agent writes new words and delivers them, so it is the only one that can agree to a date or a scope on your behalf.

A fixed autoresponder is what Gmail and Outlook already include. If that is all you need, stop here and set up Outlook automatic replies instead. Exchange and Microsoft 365 automatic replies are fixed text too, so an Exchange autoresponder tool is the same thing under another name.

• Best overall, and our pick: AI Emaily — drafts across Gmail, Outlook and IMAP, and on the Autopilot plan sends only to senders you allow-list, with a cancellable countdown and an audit log.
• Best for a shared address answered without you: Serif, which starts in draft mode and can be switched to autonomous sending for routine categories.
• Best if you cannot change email client: Fyxer, which drafts inside the Gmail or Outlook you already use and cannot send for you.
• Safest by construction: Cora, which states plainly that it will never send email for you.
• Best inside a Gmail-native client: Shortwave, whose client drafts rather than sends.
• Best for fast manual replies: Superhuman Mail, whose Auto Drafts wait for you to check and send.
• Best if you want to read the code: Inbox Zero, open source and self-hostable, drafting by default.
• Best for a plain out-of-office: Gmail's vacation responder and Outlook's automatic replies, included and predictable.

How we compared these tools#

This is a capability comparison built from vendor documentation and public product pages, rechecked in October 2026. We did not run eight tools on a live inbox for a month, and any roundup claiming it did should be read carefully. There are no prices, ratings or review counts here on purpose; check each vendor's own page on the day you buy.

Two shapes appear below, and the shape sets the ceiling. An overlay or add-in attaches to the Gmail or Outlook account you already have, and its work shows up as drafts there. A client replaces the interface and can reach across providers into one inbox, which is the difference between an add-in and an AI email assistant for Outlook that also holds your other accounts. An overlay also cannot give you an undo window on a send you press yourself.

If you only want an Outlook add-in, the Microsoft Marketplace has many. Kutools for Outlook's AI Mail Assistant drafts replies and its listing advises reviewing them before sending. Mailytica pairs suggested responses with a separate autoresponder for customer mail. Check each listing for whether it drafts or sends, and what data it passes to a third-party service.

• Autonomy — does it send by itself, draft for approval, or repeat fixed text.
• Scope — can you limit which senders or categories it may answer.
• Undo — is there a real window between the decision and the message leaving.
• Record — is every send logged, with the reason it was written.
• Failure mode — what a wrong reply looks like once it has gone.

Best AI auto-reply tools compared#

Where a cell says not documented, we could not find a public answer as of October 2026. Treat that as unknown and ask the vendor, not as a missing feature.

1. AI Emaily — best overall for replies you can leave running#

AI Emaily is an AI email client, not an overlay, connecting Gmail, Microsoft 365 and Outlook, iCloud and IMAP accounts into one inbox. We build it. Nothing migrates.

Replies run at three authority levels, set globally and overridable per rule or thread. Manual keeps agent drafts off. In Copilot, the default, approval is mandatory: every reply waits in the Agent drafts queue with a confidence score and a one-line reason, and nothing reaches a recipient until you click send. Autopilot is the only level that sends by itself, and it comes with the Autopilot and Team plans, not Pro.

Five gates then apply at once, and the first to fail holds the draft for you instead of sending it: a sender allow-list, so autonomous replies only reach domains you approved; a confidence floor you set; a cancellable countdown before each send, five minutes by default; escalate-if keywords that force review whatever the score; and optional working-hours limits. A global pause switch stops every autonomous send.

The audit log is the part that earns trust. It is append-only, and each entry carries the actor, the rule that matched, the recipient, the confidence and the full reasoning. Drafting voice comes from a Personal Context brain and client profiles you write yourself. We do not train on your mail, and model providers run under zero-retention terms.

The limits: it is a new client to learn rather than an add-in for the Outlook you already have. It runs on the web, as desktop apps for macOS (Apple silicon) and Windows, and as an iOS app; Android is coming but not live, and there is no Linux build.

2. Serif — best if you want a shared address answered without you#

Serif positions harder on autonomy than anything else here, and it is honest about where it starts. Its own wording is that it starts in draft mode, with you approving every reply, and that you can then switch routine categories to autonomous sending while sensitive messages still need approval. It connects to Gmail and Google Workspace or Outlook and Microsoft 365 through the official APIs.

It also works on shared team addresses such as info@ or support@, routing anything it is unsure about to the right person. If the goal is an alias nobody watches, that fits better than a per-sender allow-list on your own mailbox. One difference to weigh: Serif says it learns your voice from emails you have already sent, where our drafting comes from context you write yourself.

3. Fyxer — best if you cannot change email client#

Fyxer is an overlay rather than a client. It connects to Gmail or Outlook, sorts the inbox, writes draft replies and handles meeting notes, and your interface and phone app stay exactly as they are. On this post's question its answer is clear: it drafts replies in your inbox, you decide what gets sent, and it says it cannot send email on your behalf.

Two things to model first. Fyxer runs on monthly credits, and inbox sorting draws on them per labelled email, so a high-volume inbox uses them fastest; when they run out, sorting pauses. It offers a free tier and paid tiers, and its pricing page has the current allowances. The architectural limit is the usual overlay one: no single inbox across providers, and no undo window, because you are the one pressing send.

4. Cora — the safest answer on this page#

Cora works alongside Gmail rather than replacing it. Mail it judges you must answer stays in the inbox; the rest is pulled into a Brief that arrives twice a day. Replies are drafted in your voice into your normal drafts folder, and its position on sending is unambiguous: it will never send email for you, and it says it does not have the permissions to.

The limit is scope. As of October 2026 Cora supports Gmail and Google Workspace, and says Outlook and other providers are not supported yet, which rules it out for half this post's audience. Because it is not a client, the app you open each morning is still Gmail.

5. Shortwave — best AI drafting inside a Gmail-native client#

Shortwave is an AI-native client from former Google engineers, strongest on semantic search and on splitting the inbox into tabs you define. Its writing features suggest and draft replies; the client itself does not send replies on its own, and automatic drafting is described as part of Tasklet, a separate product from the same team.

Two caveats for a buying decision. Shortwave's own docs say it works only with Gmail and Google Workspace and that Microsoft 365 and Exchange accounts are not supported, so an Outlook account has nowhere to go. And its pricing page now leads with paid plans, each with a free trial, so check what, if anything, remains free before you plan around it.

6. Superhuman Mail — best for replying fast by hand#

Start with the naming, because most reviews predate it. Grammarly acquired Superhuman, the email client, in July 2025, then renamed the parent company to Superhuman in October 2025. Superhuman Mail is the client; the Superhuman Suite is the wider bundle.

On auto-reply, its answer is drafting, not sending. Auto Drafts prepares follow-ups, replies to messages that need you and scheduling replies, and leaves them for you to check and send; Superhuman's help centre lists Auto Drafts on its Business and Enterprise plans. The product is built around keyboard speed, and it works with Gmail and Outlook.

7. Inbox Zero — best if you want to read the code#

Inbox Zero is an open-source AI email assistant for Gmail, Google Workspace and Outlook. It labels and archives incoming mail, bulk-unsubscribes, and drafts replies in your voice for messages that need one. Drafting is the default, but its rule builder also lists send-reply and send-email actions, so what goes out on its own depends on the rules you write.

For this post's question it has an answer no commercial vendor can match: you can read what the code does. Every other tool here, ours included, asks you to trust a documentation page about its send behaviour. The trade-offs are familiar — self-hosting means you own setup, keys and upgrades, and the hosted plan puts you back to trusting a vendor.

8. Gmail and Outlook built-in auto-replies — included and predictable#

The built-ins cannot say anything you did not write, which makes them the right answer more often than vendors would like. Gmail's vacation responder generally replies the first time someone writes, again if the same person writes after four days while it is still on, and skips mail sent to spam or addressed to mailing lists you subscribe to.

Outlook's automatic replies send once to each person during the period, with separate replies for people inside and outside your organisation on work or school accounts. The catch is account type: Microsoft says they are not supported for Gmail, Yahoo or other POP and IMAP accounts added to Outlook, where the rules-based workaround needs Outlook left running while you are away.

When it misreads the thread: what actually goes wrong#

This is the table nobody publishes, and it predicts how a tool feels in month three rather than in a demo. Tools that only draft fail quietly and cheaply: the worst case is a bad draft you delete. Tools that send fail in public and permanently, which is why the countdown and the log are worth more than any drafting benchmark.

How to choose for your situation#

Match your line, then trial two options at most. Running four auto-reply tools at once is how people end up sending duplicate replies to the same client. If you would rather draft with AI and send by hand, our guide to using AI to respond to emails covers that workflow.

The verdict#

AI Emaily is our pick, for a reason narrow enough to check rather than take on trust: it is the only tool here that answers mail autonomously across Gmail, Outlook and IMAP while scoping that authority to senders you name, holding each send behind a cancellable countdown, and recording every action with the reasoning that produced it. Autonomy without those three is not a feature, it is an exposure.

If your requirement is that nothing ever sends unread, Cora is the better answer and we said so above. If you want a shared alias answered with nobody watching it, Serif is built for that shape. If you cannot change client, Fyxer. If you only need an out-of-office, the built-ins are more predictable than any of us.

Whichever you pick, run it in draft-only mode for two weeks before letting anything send, then widen one sender group at a time. Every tool here writes a good reply in a demo. They differ entirely in what they leave behind when the reply was wrong.