AI Email Assistant: 10 Tools Compared (2026 Pricing)

The average knowledge worker receives 117 emails a day, and most of them get under 60 seconds of attention. That number is Microsoft's, from its June 2025 Work Trend Index. Nobody reads 117 of anything properly, so a category grew up to read them for you.

Ten or so products now claim the same job. They connect to your mailbox, sort what arrives, and write the reply. Read their homepages back to back and you will struggle to tell them apart.

Three things actually separate them, and the five pages I found ranking for this search on 18 September 2026 skip all three. What the tool is permitted to do inside your mailbox. Whether it sends on its own or stops at a draft you approve. And which mail providers it supports, which quietly disqualifies one of the most recommended tools here for anyone on Microsoft 365.

I read every vendor's pricing page, help centre and provider-support documentation on 18 September 2026, and I read Google's own Gmail API permission scopes on the same day. I have not run these products side by side and I will not pretend otherwise. Everything below is what the vendors and Google publish, dated, with links at the end. If you want the broader category first, the personal AI assistant guide covers the ground around email.

How I compared them

Every tool got the same five questions on 18 September 2026. They separate this category better than a feature grid does:

• What permission does it want? Reading your mail and permanently deleting it are different asks, and Google gives them different names.
• Does it send, or does it stop at a draft? This is the single biggest behavioural difference between these products, and vendors bury it.
• Which mailboxes does it accept? Gmail, Microsoft 365, Exchange Online, iCloud, IMAP. One of the best-reviewed tools here takes only the first.
• What does the plan with AI in it cost? The headline plan is often the wrong number. On more than one vendor the entry price buys a product with the AI switched off.
• Where does your mail get processed? On your device, or on the vendor's servers, which changes what Google requires of them.

The answers come from each vendor's own pricing page, help centre and support documentation, plus Google's Gmail API scope reference. I also read the five pages ranking for this search on the same day, to see what they covered. No bake-off, no hands-on trial, no affiliate link in this post.

Quick comparison

Read the third and fourth columns before the price column. They decide more purchases than the money does.

Prices are what each vendor's own pricing page showed on 18 September 2026, except Fyxer, Superhuman and Lindy, read 17 September 2026. Missive's figures are the annual-billing rates; its page defaults to a billed-yearly toggle and monthly rates were not separately rendered. Two cells read "not verified" because I could not confirm them from the vendor's own documentation, and I would rather leave a gap than fill it.

What email actually costs you

Microsoft's Work Trend Index report "Breaking down the infinite workday", published 17 June 2025, is the most recent serious measurement of this. It combines a survey by Edelman Data x Intelligence of 31,000 knowledge workers across 31 markets, fielded 6 February to 24 March 2025, with aggregated Microsoft 365 telemetry.

Four findings from it are worth carrying into a buying decision. Workers receive 117 emails a day, most skimmed in under 60 seconds. They are interrupted every 2 minutes during focus work, and they take 153 Teams messages on a weekday on top of the mail. Of the people online at 6am, 40% are already reviewing email to work out the day's priorities. And mass emails sent to 20 or more recipients are up 7% year on year, which is a polite way of saying the volume problem is getting worse.

The 6am finding is the one that should shape what you buy. If your first act of the day is sorting mail into what matters, then triage is the job, and drafting is a bonus. Inbox triage on its own is a smaller purchase than a new email client.

Where the 28% figure comes from

You have seen the claim that workers spend 28% of the workweek, roughly 11.2 hours, on email. It is usually credited to Microsoft's Work Trend Index. It does not appear in that report.

The figure traces to McKinsey Global Institute's 2012 study The Social Economy. That makes it 14 years old, from a working world before Slack was widely adopted, before Teams existed, and before a phone buzzed every time a thread moved. Quote it if you like, but attribute it to McKinsey in 2012 and say how old it is. A vendor who cites it as current research has not checked.

What these tools are allowed to do to your mailbox

Every product on this page asks you to click through an OAuth consent screen. Most people read that screen the way they read a cookie banner. Google publishes exactly what each permission covers, in plain English, and the gap between the mildest and the broadest one is very wide.

The Gmail permission ladder, in plain words

These are Google's own scope names and its own classifications, from the Gmail API authorisation documentation I read on 18 September 2026.

Source: Google, Gmail API OAuth 2.0 scopes reference, read 18 September 2026. Quoted phrases are Google's.

Three lines in that table deserve a second read. gmail.compose sounds like a drafting permission. Google's own description is "Manage drafts and send emails", so granting it grants sending. gmail.modify is the workhorse scope for assistants that label, archive and reply, and Google is explicit that it withholds permanent deletion. The full https://mail.google.com/ scope does not withhold it. An app holding that one can erase a message past the trash, and there is no undo on the far side of that.

The lesson is small and useful: on the consent screen, look for the word "permanently". A tool that only needs to sort and draft has no reason to hold the broadest scope, and a tool that asks for label management alone is asking for the mildest thing on the ladder. If you want the step-by-step version of this decision, how to give an agent access to your email safely walks through it.

The question to ask before you connect anything

Restricted scopes come with an obligation, and it falls on the vendor. An app requesting them has to go through Google's OAuth verification. And if that app stores or transmits restricted-scope data on its own servers, it also has to pass a third-party security assessment, the one Google refers to as CASA.

So the useful question for a sales rep is more specific than "is it secure". Ask two questions with checkable answers. Does my mail sit on your servers, or is it processed on my device? And if it sits on your servers, did you pass that assessment, and when?

A vendor doing this properly will answer both in a sentence, usually with a security page to point at. A vendor who answers with the word "enterprise-grade" and nothing else has told you something too.

One dated precedent, from 2019

This is history, not a current warning, and I want to be clear about that before the detail. On 4 July 2019, ITPro and others reported that Superhuman shipped read receipts switched on by default, implemented with tracking pixels. Recipients had no way to opt out, and senders could see when a message was opened, how many times, and on what device and from roughly where.

Superhuman changed it. The company stopped location tracking, deleted the location data it had collected, and turned read receipts off by default. Founder Rahul Vohra apologised publicly at the time, saying the company had not considered the potential bad actors and had not thought the feature through fully.

That was seven years ago and it was fixed. I include it because it is the cleanest public example of the real risk in this category, which is rarely a breach. It is a default that exposes somebody who never installed your software and never agreed to anything. When you evaluate an email assistant, check what it does on behalf of your recipients, not only what it does for you.

Draft only, or does it actually send?

The five ranking pages I read mention this in passing. None of them tabulates it, which is strange, because it is the one thing that determines how nervous you should be on day one.

Behaviour as documented by each vendor and read on 18 September 2026, except Fyxer, Superhuman and Lindy, read 17 September 2026.

Nine of the ten stop at a draft. That is the category norm, and it is a sensible one, because a wrong reply sent to a client is a much more expensive mistake than a wrong draft sitting in your outbox folder.

Lindy is the exception, and it deserves precise wording. Lindy exposes an "Ask for Confirmation" toggle on actions that have side effects, and sending email is one of them. Set it to Always and the agent drafts, then waits for your approval, which reaches you as an email or shows up as a draft in the task view. Leave it off and the agent sends. The control belongs to you and it is a toggle, not a support ticket.

I could not verify what that toggle is set to out of the box, so I am not going to tell you. It is load-bearing enough that a guess would be worse than a gap. Open the action, read the toggle, then decide.

Which mailboxes each one supports

This is the quietest disqualifier in the category. People pick a tool on reviews, reach the sign-in screen, and find their address is not welcome.

Provider support as documented by each vendor on 18 September 2026. SaneBox, Lindy and Gravity are out of this table: the first two were not verified against vendor documentation for this post, and Gravity connects Gmail and Google Workspace through an ordinary sign-in.

The Shortwave row is the one to sit with. It is a genuinely good product and it is recommended constantly, including by ranking pages I read that never mention it needs a Google account to sign in. If you are a Microsoft 365 shop, Shortwave is off your list before you compare a single feature, and the honest alternatives are Spark, Superhuman, Fyxer, Serif or Missive. Outlook email triage with an agent covers the Microsoft side in detail.

1. Gravity: best when you want the inbox job finished, not a new email client

This is my product, so discount me accordingly. It is first because it is the only entry here that does not ask you to change how you read mail.

You describe the job in plain words. Gravity matches it to an agent an independent builder already made and tested, you sign in to Gmail through an ordinary Google login, and it runs on a schedule. No API keys, no canvas, no new client to learn. Triage the overnight mail and label it, pull the attachments out and file them, draft the replies that follow a pattern, send the morning summary.

Anything that messages a customer or moves money pauses and waits for you. Every agent passes automated checks before it is listed. If a run fails on a confirmed platform error and produces no usable output, it is refunded under the refund policy.

Every customer-facing step waits for you

The other tools on this page sell you a better place to do email. Gravity sells the finished worker for one repeated job, and the builder who published it keeps it working. That responsibility sits with the builder. Running an AI agent on Gmail shows what one of these looks like end to end.

Best for

An owner-operator or a small team whose email problem is really one repeated job: triage, filing, chasing, or the same four replies every week.

Pricing

First agent free, no card. Then Pro at $5 a month during the alpha, or Max at $20 a month for more agents and usage. Buy more usage if you run out. As of September 2026.

Free tier

Yes. One agent, free, no card.

Verdict

Pick this when the outcome matters more than the interface. Gravity is in private alpha, so the honest step is to apply and describe the task.

2. Shortwave: the most capable AI client, if you are on Google

Shortwave is the one people in this category recommend to each other. It bundles an AI assistant into a rebuilt Gmail experience: it drafts replies, and it also auto-labels, stars and archives, which puts more of the triage work on the machine than most of its rivals attempt.

Pricing is Business at $30, Premier at $45 and Max at $120 per seat per month, as of September 2026. Notably, the page shows monthly rates only, with no annual option and no discount for committing. There is a 14-day trial and no free tier, so the cheapest way in is $30.

The Gmail requirement is a hard stop for Microsoft 365

Shortwave requires a Gmail or Google Workspace account to sign in. Microsoft 365 and Exchange are not supported. An Outlook.com address can forward mail in, but you cannot send from it. Yahoo, iCloud, Fastmail and Zoho are in the same forwarding-only position. For a Google-native team this barely registers; for everyone else it ends the evaluation. Its own auto-labelling overlaps heavily with Gmail label automation by agent, which costs considerably less if labelling is the only thing you want.

The verdict is short. Shortwave is the best-built product on this list for the people it accepts, and completely unavailable to the people it does not.

Best for

A team already living in Google Workspace that wants the machine to do more of the triage than a drafting tool attempts.

Pricing

Business $30, Premier $45 and Max $120 per seat per month, monthly billing only, with no annual discount shown. As of September 2026.

Free tier

No. A 14-day trial, then $30 a seat.

Verdict

Worth $30 a seat if you are on Google and want automatic labelling and archiving as well as drafts. Check the sign-in requirement before anything else.

3. Superhuman: speed as the entire product

Superhuman sells keyboard speed first and AI second. The pitch has always been that you clear your inbox faster, and the AI writing features arrived on top of that rather than replacing it. It drafts; it does not send for you.

Speed is the product and the AI is the addition

Pricing is Starter at $25 and Business at $33 per member per month, billed annually, verified 17 September 2026. There is no free tier. It is also the tool with the 2019 read-receipts history described above, which the company fixed at the time. Worth knowing, and settled history as far as the 2026 product goes.

4. Fyxer: an AI layer, so you do not move house

Fyxer is an overlay rather than a client. It connects to Gmail or Outlook, organises what arrives, and writes drafts into the inbox you already open every morning. Its own help centre puts it plainly: it "puts drafts in your inbox, ready to review and send".

Pricing verified 17 September 2026: Starter at $22.50 a month billed annually or $30 monthly, and Professional at $37.50 annually or $50 monthly.

It sits on top of the inbox you already have

That is the whole argument for Fyxer and it is a good one. Switching email clients is a real cost, in muscle memory and in the week where you cannot find anything. An overlay skips it. The trade is that you get a narrower product, because Fyxer only prepares the mail and leaves the reading experience alone.

5. Serif: drafts that sound like you

Serif's angle is voice. It learns how you write and produces drafts in that register, which matters more than it sounds, because the fastest way to abandon one of these tools is to keep rewriting its output. It connects to Gmail or Outlook in one click, and IMAP does not appear in its documentation.

The plans are Lite at $30, Standard at $50 and Pro at $200 per month, with a Team plan at $50 per user per month, as of September 2026. Pro is the highest single-seat price in this comparison by a wide margin, so work out what the upper tiers buy before you assume you need them. The trial is 7 days with full access, short but unrestricted.

Start on Lite and judge one thing during those seven days: how often you rewrite what it produces.

6. Missive: the one built for a shared address

Missive solves a different problem from the rest of this page. It is built for two or more people working one inbox, the support@ or hello@ address where somebody has to decide who answers. Its AI writes drafts, and its rules route and label incoming mail so the deciding happens less often.

It is also the widest channel coverage here. Alongside Gmail, Outlook and IMAP it carries WhatsApp, Messenger, Instagram and SMS in the same threads, which is unusual and genuinely useful for a business whose customers do not all use email.

Shared inbox first, assistant second

Pricing is Starter $14, Productive $24 and Business $36 per user per month, and those are the annual-billing figures: the pricing page defaults to a billed-yearly view with a 20% discount applied, and monthly rates were not separately rendered when I read it on 18 September 2026. The trial is 30 days of Productive with no card, the most generous on this page. For the same job in Front, an agent on a Front shared inbox is the closer comparison.

Best for

A team of two to twenty sharing one customer-facing address across several channels.

Pricing

Starter $14, Productive $24, Business $36 per user per month, billed annually. As of September 2026.

Free tier

No, but 30 days of Productive without a card.

Verdict

The right answer for a shared address, and more product than a solo user needs.

7. Spark: the widest mailbox support, and a real free tier

Spark accepts more kinds of mailbox than anything else in this comparison. Gmail and Workspace, Outlook and Microsoft 365 including Exchange Online, iCloud, Yahoo, and any standard IMAP account. If your address is unusual, start here.

The AI drafts replies, and the client can archive or delete mail by sender, which is the sort of blunt rule that clears a lot of noise quickly. It does not send on its own.

The cheapest paid plan on this page

Spark also has the only genuine free forever plan here, with the AI limited to a preview. Paid is Plus at $10 a month, or $8.25 a month when billed annually, and Pro at $20 a month, or $16.58 a month when billed annually, as of September 2026. Those are the lowest paid prices in this post, and by a distance.

Spark is the default recommendation for a personal mailbox on this page, mostly because it will actually accept your address.

Best for

A personal mailbox on iCloud, Yahoo, Exchange Online or a plain IMAP host, where most of this category refuses to sign you in.

Pricing

Free forever tier. Plus $10 a month, or $8.25 a month when billed annually. Pro $20 a month, or $16.58 a month when billed annually. As of September 2026.

Free tier

Yes, free forever, with the AI features limited to a preview.

Verdict

Start here if your address is unusual. Treat the free tier as a way to test the client, then pay if you want the AI properly.

8. Mailbutler: the plan trap worth knowing about

Mailbutler is an add-in rather than a client. It works inside Apple Mail, Outlook and Gmail, so the thing you open every day does not change. Current documentation names those three; I did not confirm general IMAP support for the AI features, so treat that as an open question rather than a yes.

The $9 plan has no AI in it

Now the part that catches people. Professional at $9 a month, or $7 on annual billing, has no AI in it. The AI features start at Smart, which is $14 a month or $11 annual, and Business is $32 a month or $24 annual. The Starter plan is free forever, and it adds a watermark to your outgoing messages. There is a 14-day full trial.

If you compare this category on entry price alone you will put Mailbutler at $9 next to Spark at $10 and reach the wrong conclusion. The comparable number is $14. Check which plan the AI lives on before you compare anything, because Mailbutler is not the only vendor who prices this way.

9. SaneBox: sorting, with no writing at all

SaneBox is the oldest idea on this page and still a defensible one. It does not write your email. It decides what deserves your attention, files the rest into folders you learn to trust, and leaves the inbox holding only what is left. For a lot of people that solves the actual problem, since the 6am Microsoft finding is about triage rather than composition.

On pricing I have one verified number and I am going to be straightforward about the rest. SaneBox's own help pages say plans "start at just $7 per month". Its pricing page is rendered in JavaScript and returned no price data across three attempts on 18 September 2026, and the third-party aggregators that list per-plan figures contradict each other, so I am not repeating any of them. The floor is $7; check the current plan table yourself before you buy.

If filing is the whole job, an agent can do the narrower version of it for less. Filing Gmail attachments automatically is the tightest example.

10. Lindy: the only one that can send without you

Lindy arrives at email from a different direction. It is an agent builder with email among its skills, which is why it behaves differently from everything above it on this page. You assemble an assistant, give it triggers, and it acts.

Pricing is Plus at $29.99, Pro at $99.99 and Max at $199.99 per user per month, with a 7-day trial, verified 17 September 2026. Seat count is the number to watch, because this prices per person and the capability tempts you to add people.

The confirmation toggle, and what I could not verify

Lindy puts an "Ask for Confirmation" toggle on actions that have side effects, and sending email is one of those actions. Set it to Always and the agent prepares the message, then holds. The approval request reaches you as an email, or appears as a draft in the task view. Leave the toggle off and the agent sends on its own.

What I could not verify is what that toggle is set to when you first create an email-sending action. I looked, I did not find a documented answer, and it is too consequential to guess at. Open the action and read the toggle before you turn anything loose on a real mailbox.

What Gmail and Outlook already include

Before you buy anything, check what you are already paying for. Google announced on 15 January 2025, on its Workspace Updates blog, that it was "including the best of Google AI in Workspace Business and Enterprise plans without the need to purchase an add-on", and it discontinued the separate Gemini Business and Gemini Enterprise add-ons at the same time.

So a Workspace Business or Enterprise subscriber already has AI drafting and summarising inside Gmail without buying a tenth product, and Microsoft sells a comparable capability for Outlook through Copilot. I am deliberately not quoting a price for either. Google Workspace pricing is served by geography and returned Indian rupees to my machine, and Microsoft's Copilot pricing pages timed out on both attempts. Open your own admin console and read your own currency.

What the built-in options do not give you is autonomy or scheduling. They help while you are in the mailbox. Everything on this page runs whether you are there or not, and that is the line between a writing aid and an assistant.

Which one should you choose?

Start with the mailbox, because it removes options faster than anything else. If you are on Microsoft 365, cross Shortwave off now. If your address is iCloud, Yahoo, Fastmail or anything IMAP, Spark is close to the only complete answer here.

If the real complaint is triage rather than writing, SaneBox at $7 a month or a narrow agent will solve it for a fraction of what a full client costs. Most people describe an inbox problem and buy a composition tool.

Shortwave is the best-built AI client here for teams that live in Google Workspace. If speed is the thing you actually want rather than automation, Superhuman is the honest answer. For a shared support address, Missive, and it handles WhatsApp and Instagram in the same view.

For someone who will not leave their client, Fyxer or Mailbutler, remembering that Mailbutler's AI starts on the $14 Smart plan. If you want an assistant that acts on its own, Lindy is the only one here that will, and you should set the confirmation toggle deliberately on day one.

My own bias, stated plainly. For a job you repeat every week, I would rather hand over the job than the client. That is what Gravity does: an agent someone already built runs the triage inside your existing Gmail, drafts the replies, and waits for you before anything reaches a customer. It is in private alpha and the first agent is free. If cost is the deciding factor across this whole category, the cheapest AI agent platforms compares the money side properly, and inbox zero with Asana covers the case where email is really project admin.

FAQ

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