The best AI email assistants compared
Products marketed as AI email assistants do very different jobs, at very different prices. This roundup compares the ones people actually use, what each is best for, and how they fit into a Gmail or Outlook workflow.
How we compared
- Does it triage automatically, or only help you write? Sorting and prioritizing are what reduce time in the inbox.
- Does it work with the mail you already use, or does it force you to switch clients?
- What does it cost, and is there a free trial long enough to test it on real mail?
- How much setup does it need before it helps?
The tools, side by side
| Tool | What it does | Works with | Price | Best for |
|---|---|---|---|---|
| Cerno AI(we build this one) | A triage-first assistant you forward mail to. It reads every message, sorts it into categories, adds a priority, writes a one-line summary and drafts replies you can send in a couple of taps. Voice listen and reply plus send-later scheduling are built in. | Gmail, Outlook and custom domains via forwarding | 7-day free trial | Anyone drowning in volume who wants sorting, summarizing and drafting in one place without switching mail clients. |
| SaneBox | AI that filters your existing inbox into folders such as SaneLater and SaneNews, so only important mail lands in your main view. | Every major email client; nothing to download | Free trial, no credit card; plans from about $7/month | Keeping newsletters and noise out of an inbox you want to keep using exactly as it is. |
| Shortwave | An AI-native Gmail client, built by former Google Inbox engineers, with message summaries, AI search, bundles and an assistant you can chat with. | Gmail accounts; iOS, Android, desktop and web | From $24 per seat/month billed annually; 14-day trial | People who want to replace their Gmail app with an AI-first client and are happy to switch apps. |
| Mailbutler | A productivity add-on for Apple Mail, Gmail and Outlook covering email tracking, mail merge, signatures, send-later and AI writing help. | Apple Mail, Gmail and Outlook | 14-day free trial; paid subscription | Power users who want tracking, signatures and merge in the client they already use. |
| Superhuman | A fast premium mail client with keyboard-first workflows, AI triage and auto drafts. | Gmail, Outlook and other accounts it can connect to | From $25 per member/month billed annually; free trial | Individuals and teams who want speed and polish and are willing to pay a premium for it. |
| Gemini in Gmail | Google's AI built into Gmail: summarize long threads, draft replies and get caught up without leaving the app. | Gmail on desktop and mobile with an eligible Google AI or Workspace plan | Included with eligible Google AI / Workspace plans | Gmail users who want AI help inside the mail client they already live in. |
Prices are what the providers list publicly and can change; check each product's site before deciding.
Which one should you pick?
Volume is the problem, and you want to stay in your current client
Look at a forwarding-based triage assistant such as Cerno AI or SaneBox. Cerno AI adds what SaneBox does not: per-message summaries, priority scoring and one-tap draft replies, so the sorting comes with the context to act on it.
You are happy to switch apps and live in Gmail
Shortwave is the strongest AI-first Gmail client, and Superhuman the fastest premium option if speed and polish matter more than AI depth.
You want tracking, merge and signatures in your current client
Mailbutler layers those on top of Apple Mail, Gmail or Outlook without changing how you work. It is an add-on rather than a triage assistant.
You just want Gmail to do a bit more
Gemini in Gmail summarizes long threads and drafts replies with no new app to learn, if you have an eligible Google plan.
Where Cerno AI fits
Cerno AI is a triage-first assistant. Mail forwarded to your Cerno AI address is read on arrival, summarized in a line or two, given a category such as clients, transactions or promotions, and marked with a priority. Replies are suggested where a message needs one, so the writing help sits inside the triage rather than replacing it.
Because it works by forwarding, it does not care whether your mail lives in Gmail, Outlook or a custom domain, and you can point a single label at it before moving anything else.
Choosing an AI email assistant
What makes an AI email assistant the best for me?
It depends on your problem. If volume is the issue, you want automatic triage: sorting, summarizing and prioritizing before you open the inbox. If composing is the issue, you want writing help. If speed matters most, a premium client may be worth the price. Start with what is eating your time, then pick the tool that targets that.
Do I have to switch email providers to use one?
No. Forwarding-based assistants like Cerno AI work with Gmail, Outlook or a custom domain, and you can point a single label at them before moving anything else. Some products (like Shortwave or Superhuman) are apps you switch to, which is a bigger change.
Is it safe to let AI read my business email?
It depends on the provider's retention and subprocessor policy, which you should read before connecting anything. Cerno AI documents what is stored, which AI subprocessors process message content and how long data is kept in its privacy policy.
How is this page different from your AI email assistants guide?
That guide compares the three categories of assistant (triage, writing and rules). This page ranks specific products so you can see, at a glance, what each one is best for and what it costs.