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The best AI email assistants

A ranked list is only useful if you can see the ranking rule. This one checks eight tools against seven criteria using each vendor's own pages, and orders them by how many criteria they meet. Synced is on the list, written by the Synced team, and it isn't first.

By the Synced team · Updated

In short

Checked against seven criteria on September 13, 2026, the best AI email assistants were Fyxer, Superhuman Mail, Spark Mail, Synced, ChatGPT, Copilot in Outlook, Shortwave, and Gemini in Gmail, in that order. Fyxer met every criterion: it drafts replies on its own, never sends without approval, supports Gmail and Outlook, is generally available with a free trial, and says your data isn't used for model training. Synced, the AI inbox assistant, ranked fourth because it is still in private beta.

The seven criteria used to rank AI email assistants

  1. Drafts replies with AI inside your email workflow, not only in a separate chat.
  2. Prepares drafts without you prompting for each one.
  3. Doesn't send AI-written email unless you approve it, by default.
  4. Works with both Gmail and Outlook.
  5. Is generally available, with self-serve pricing published on the vendor's site.
  6. Has a free plan or a free trial.
  7. Publishes a policy that your email data isn't used to train AI models, for the plan an individual or small team would buy.

Each tool gets Yes, Partial, or No per criterion. The order is the number of Yes answers, with Partial counting as half. Ties go to the tool that is generally available, then to broader email provider support, then to having a free plan. Price isn't a criterion on its own because the right price depends on what you already pay for, but every entry lists it.

AI email assistants compared against the criteria

RankToolDrafts in emailDrafts unpromptedApproval by defaultGmail and OutlookGenerally availableFree plan or trialNo-training policy
1FyxerYesYesYesYesYesYes (trial)Yes
2Superhuman MailYesYesYes (auto-send optional)YesYesYes (free month offer)Partial
3Spark MailYesNo (Auto-Drafts coming soon)YesYesYesYesYes
4SyncedYesYesYesYesNo (private beta)YesYes
5ChatGPTPartial (via plugins)Partial (scheduled)YesYesYesYesPartial
6Copilot in OutlookYesNoYesPartial (Gmail by linking)YesYes (trial)Yes
7ShortwaveYesPartial (via Tasklet)Partial (not stated)No (Gmail only)YesYesYes
8Gemini in GmailYesPartial (suggested replies)YesNo (Gmail only)YesYes (Workspace trial)Partial

Checked September 13, 2026 against each vendor's own pages. Ties: Spark over Synced (general availability), ChatGPT over Copilot (provider support), Shortwave over Gemini (free plan).

1. Fyxer

Fyxer works inside Gmail or Outlook, sorts mail into categories like To Respond and FYI, and drafts a reply in your voice for emails that need one. Its security page says it will never send an email on your behalf and that your data is never used to train third-party AI models. It also joins video meetings to take notes. Starter is $22.50 per user per month billed annually, after a 7-day trial. Best for Gmail or Outlook users with a lot of meetings. See Synced vs Fyxer.

2. Superhuman Mail

Superhuman Mail is a fast email client for Gmail and Outlook on Mac, Windows, web, iOS, and Android, with Write with AI, Instant Reply, and Auto Drafts on its Business plan. It can also send emails on your behalf if you choose, which is why approval is marked as the default rather than the only mode. Model training scored Partial: Superhuman prohibits its AI providers from training on your data, while its suite plans page lists model training as opt-out on Business. Starter is $25 and Business $33 per member per month billed annually. See Synced vs Superhuman.

3. Spark Mail

Spark is a cross-platform email app for Gmail, Outlook, iCloud, Yahoo, and IMAP with a Free plan, and +AI tools that draft from a prompt for you to review and send. Its privacy policy says it doesn't use your data to train any AI model. It misses one criterion today because Auto-Drafts is listed as coming soon. Plus is $10 a month or $99 a year. See Synced vs Spark.

4. Synced

Synced is an AI inbox assistant that reads new messages from Gmail and Outlook, as well as Slack, Microsoft Teams chats, WhatsApp Business, Instagram Business DMs, Messenger, SMS, and GroupMe. For each message it writes an Action Plan that can include a draft, a file from Drive or OneDrive, and open times from Google Calendar, and every AI-drafted message waits for approval. It ties Spark on criteria and ranks below it because Synced is in private beta: access is by waitlist, and it runs on desktop browsers and iPhone only. The Free plan covers 20 Action Plans a week; Pro is listed at $29.99 per user per month.

5. ChatGPT

ChatGPT connects to Gmail and Outlook through plugins and can review your inbox and draft replies on a schedule, following OpenAI's inbox guide that asks before sending or deleting. Drafting scored Partial because it runs through ChatGPT rather than inside your email app. Model training scored Partial because OpenAI's documentation we could access covers Business, Enterprise, and Edu, not individual plans. Plus is $20 a month. See Synced vs ChatGPT.

6. Copilot in Outlook

Draft with Copilot writes full emails in Outlook from a prompt and the thread, and you keep, edit, and send them. Microsoft Learn says prompts, responses, and Microsoft Graph data aren't used to train foundation LLMs. Gmail works only by linking the account to a Microsoft 365 subscription in new Outlook. Copilot Business is $21 per user per month paid yearly, on top of a qualifying Microsoft 365 plan. See Synced vs Copilot in Outlook.

7. Shortwave

Shortwave is an AI-first email client with AI search, AI filters, and a free plan, and its security page says your data is never used to train third-party LLMs. It ranks lower here mainly because it supports Gmail and Google Workspace only, and because automatic drafting runs through a separate product, Tasklet. Paid plans start at $30 per seat per month. See Synced vs Shortwave.

8. Gemini in Gmail

Gemini is built into Gmail for Workspace customers and Google AI plan subscribers, with Help me write, summaries, and Contextual Smart Reply. It's Gmail-only by definition. Model training scored Partial because Google's Workspace commitment not to train without permission doesn't cover personal accounts, where Google says it removes personal information from data used to train Gemini. Workspace Business Starter is $7 per user per month. See Synced vs Gemini in Gmail.

Tools we checked but didn't rank

SaneBox is a long-running email filter for nearly any provider, from $9.49 a month, but writing replies isn't among its listed features, so it doesn't fit these criteria. If sorting is your main problem, see SaneBox alternatives. We'll recheck this list as vendors change plans; the date on every row is the date we looked.

How we evaluated

  • Every fact about another company comes from that company's own pricing page, product page, documentation, or privacy policy, fetched on September 13, 2026 and linked below. Third-party reviews and roundups weren't used.
  • Where a vendor's page didn't state something, we scored it Partial or No and said so, rather than guessing.
  • Pages that blocked automated access (OpenAI's main pricing and help-center pages) were skipped, and ChatGPT was scored only on OpenAI documentation we could read.
  • Synced facts come from Synced's own pricing and security pages. The Synced team wrote this page, which is the reason for publishing the criteria and the tie-break rules.
  • No tool was tested for draft quality. Quality depends heavily on your mail, so try two or three with a free plan or trial on a week of real messages. The evaluation guide has a checklist.
Questions

Frequently asked.

What is the best AI email assistant for Outlook?

Against these criteria, Fyxer, Superhuman Mail, Spark Mail, and Synced all support Outlook fully. If your company already has Microsoft 365, Copilot in Outlook adds drafting without another vendor, though it needs a Copilot license on top of the Microsoft 365 plan.

Which AI email assistants never send email without approval?

Fyxer, Spark Mail, Synced, Copilot in Outlook, and Gemini in Gmail describe drafts you review and send. Superhuman Mail can send on your behalf if you turn that on. Shortwave's docs that we checked don't state a policy.

Is there a free AI email assistant?

Spark Mail, Shortwave, ChatGPT, and Synced list free plans, with AI limits that vary. Fyxer, Superhuman, Copilot, and Google Workspace offer free trials or a free month instead.

Why isn't Synced ranked first on its own site?

Because it doesn't meet one of the criteria yet. Synced is in private beta, so it isn't generally available, and it tied Spark Mail on the rest. The tie-break rule favors generally available tools.

Keep reading

Related.

Evaluate an AI email assistantA 12-point checklist and a one-week trial plan for choosing an AI email tool on evidence, not demos.Fyxer alternativesSeven tools that write email drafts for you, sorted by how much of the drafting starts without a prompt.PricingFree, Pro, and Enterprise plans, Action Plan limits, and billing FAQ.Security and data controlsHow Synced protects connected data and keeps users in control.
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