Superhuman vs Shortwave for Outlook Users: Which One Works?

Superhuman vs Shortwave for Outlook users is a shorter comparison than it looks. Most head-to-heads between these two argue about drafting quality, search and keyboard speed. If your mail lives on Microsoft 365, none of that gets a vote — one of the two cannot open your mailbox at all.

So this post spends its first half on the fact that decides it, and its second half on what you should actually check before you hand over a card. We build an email client too; it gets one short section near the end and nothing more.

The short answer#

Shortwave requires a Gmail or Google Workspace account to sign in. Its own documentation lists Microsoft 365 and Exchange as not supported. We re-checked that page on 30 July 2026 and it still says so.

Superhuman Mail supports Outlook natively. The company shipped Outlook support in 2022 and, in 2024, described its coverage as every combination of Gmail and Outlook across Mac, Windows and Web, plus iOS and Android.

For a genuine Outlook shop, that resolves the comparison before features enter into it. The useful questions left are narrower: does Superhuman Mail cover your particular Microsoft setup, and what does it cost you if you try to force Shortwave to work anyway?

What Shortwave's documentation actually says#

Shortwave publishes one page on this, and it is unusually direct. Sign-in requires a Gmail or Google Workspace account. Microsoft 365 and Exchange are marked as not supported at this time. Outlook.com, Hotmail and Live are marked as forwarding only, cannot send from address.

The documented path for anything non-Gmail is a workaround, not a connection. You set up auto-forwarding at the source provider into a Gmail account, configure Gmail's "Send mail as" using the provider's SMTP server and an app password, then sign into Shortwave with the Gmail account.

For Microsoft consumer addresses, Shortwave's page says the send half of that does not work. Mail arrives in Gmail; replies leave as your Gmail address. That is the vendor's own description, not a reviewer's complaint.

What the forwarding workaround really costs#

People do run this setup, so it is worth pricing honestly rather than dismissing. The costs are not evenly spread — two of them are dealbreakers for client-facing work and the rest are ongoing friction.

The parts no workaround touches#

Forwarding moves messages. It does not move the things that make a Microsoft mailbox a Microsoft mailbox.

Shared mailboxes, delegate access, Exchange calendar with rooms and free/busy, retention and legal-hold policies, and conditional-access rules all stay on the Microsoft side. In a real Microsoft 365 organisation those are usually load-bearing, not nice-to-haves.

If your day involves a support@ mailbox, an assistant managing your calendar, or an IT policy you did not write, the forwarding route is not a workaround. It is a different, smaller mailbox that happens to receive copies of your mail.

What Superhuman Mail gives an Outlook user#

Superhuman rebuilt the client against Microsoft's API rather than wrapping the Gmail one — the company has said publicly that Gmail and Outlook have completely different APIs and that the work amounted to a rebuild. The visible result is that the core product is genuinely present on Outlook: split inbox, the command palette, shortcuts, snippets, reminders, undo send, and moving mail into folders rather than labels.

One disambiguation first, because it changes what you are buying. Grammarly acquired Superhuman in July 2025 and renamed the parent company Superhuman in October 2025. Superhuman Mail is the email client; the Superhuman Suite is the bundle around it. If the page you are reading never says which one it means, it is not a page to trust on features either.

What we would not assume from the marketing: Superhuman's public Outlook pages do not publish a feature-parity matrix against Gmail, and they do not enumerate which Microsoft account types qualify. That is not a criticism, it is a gap you should close yourself during the trial.

The one case where Shortwave still wins#

If "Outlook user" means a personal Outlook.com address you barely touch while your company runs on Google Workspace, you are a Google Workspace user with a legacy alias. In that case Shortwave is the stronger product, and it is not close either: its natural-language search across the mailbox and its AI filters do things Superhuman Mail does not attempt.

The second case is narrower. If you have already decided to leave Microsoft for Google Workspace, evaluate Shortwave against the mailbox you are moving to, not the one you are leaving.

What is not a case: keeping Microsoft 365 and routing it into Gmail so you can use Shortwave. The table above is the invoice for that decision.

Who each one is for#

A third option, honestly#

Disclosure: we build AI Emaily, so weigh this accordingly. It sits in one block near the end rather than threaded through the comparison, because this post is about the other two.

The relevant claim is narrow and checkable: we connect Outlook.com, Hotmail and Microsoft 365 natively through one-click Microsoft sign-in — no forwarding, no second mailbox, replies from your real address. Gmail, Google Workspace and standard IMAP connect the same way, in the same inbox, which is the case Superhuman Mail does not cover and Shortwave cannot. Setup steps are at /docs/connect-outlook.

The agent runs in three authority modes — Manual, Copilot and Autopilot. In Copilot nothing sends without your approval, Autopilot is gated, and every agent action is undoable and written to an audit log. Drafts come from a Personal Context you write yourself plus per-client profiles you set, not from a model reading your archive, and we do not train on your mail.

Where we are behind, we are behind. Superhuman Mail's keyboard fluency is better than ours, and Shortwave's search over a Gmail archive is better than ours. Our limits, stated plainly:

• macOS and Windows ship as downloadable desktop apps built as an Electron shell around the web interface, not hand-built native binaries. The Mac build is Apple Silicon only and is not in the Mac App Store.
• There is no Linux build. Linux users get the web app.
• iOS is a native App Store app. Android is a PWA today, with a native app on the roadmap rather than shipped.
• Offline support is partial by design: read and draft offline, but there is no complete local archive.

The call#

On Microsoft 365 or Exchange, of these two it is Superhuman Mail, because Shortwave will not sign you in. Spend the trial confirming the six items in the checklist above rather than admiring the shortcuts.

On Google Workspace with a stray Outlook address, it is Shortwave, and the rest of this post does not apply to you.

Both are per-seat subscriptions and both changed their plan structure in the past year, so we quote no figures here. Check each vendor's own pricing page on the day you buy, and be suspicious of any comparison — including a July 2026 one — that hands you a number without a date attached.