Honest comparison
Superhuman Alternative: A True Unified Inbox Across Every Provider, Sorted by AI
Connect every mailbox you own to one board, in the browser, and let AI read each message to categorize it and flag spam before you open it.
Any IMAP provider · AI category + spam per message · Two-way sync
In short
Superhuman, now Superhuman Mail after Grammarly bought it in 2025, is a fast, keyboard-driven email client for Gmail and Outlook that costs $30 per user per month, or $25 billed annually, on its Starter tier. It is built for speed on one account and does not offer a true unified inbox (its own help docs call the multi-account setup a workaround) or generic IMAP. Inboxes is a different shape: a browser board that unifies every IMAP mailbox and has an AI model categorize each message and flag spam. If you want the fastest keyboard client on a single Gmail or Outlook account, buy Superhuman. If you want one sorted board across many providers, that is what Inboxes is for.
The difference
Where Inboxes and Superhuman actually diverge
Superhuman earned its reputation on speed. The keyboard shortcuts, the sub-100-millisecond feel, Split Inbox, and now an AI layer (Auto Drafts that wake up written in your voice, Ask AI across your inbox and calendar, Auto Summarize) make it the fastest way a lot of people have found to clear a busy Gmail or Outlook account. Since Grammarly acquired it in July 2025 and renamed the company Superhuman later that year, it also ships alongside Grammarly writing tools. Two things push people to look for an alternative. The first is reach: Superhuman connects Gmail, Google Workspace, Outlook, and Microsoft 365, and nothing else, so iCloud, Yahoo, Fastmail, and mail on your own domain are simply out. The second is that it has no real unified inbox. Superhuman own help center describes running several accounts as a tab-based workaround rather than one merged board. Inboxes takes the other side of both. It connects any IMAP mailbox, and it puts every one of them on a single board where an AI model reads each incoming message, assigns a category (work, personal, receipts, newsletters, notifications), and decides whether it is spam. It does not draft your replies. It reads and sorts your mail so the board you open is already triaged.
Side by side
Inboxes vs Superhuman
| Capability | Inboxes | Superhuman |
|---|---|---|
| Unified inbox across every account | Yes | Accounts run as tabs (their docs call it a workaround) |
| Any IMAP mailbox (Gmail, Outlook, iCloud, Yahoo, own domain) | Yes | Gmail and Outlook only |
| AI categorizes every message automatically | Yes | Auto Labels and Split Inbox |
| AI spam detection on top of the provider filter | Yes | No |
| AI that drafts and rewrites your replies | No | Yes |
| Native desktop and mobile apps | No | Yes |
| Free tier | No | No |
| Entry price | $29/mo flat | About $25 to $30/user/mo billed annually |
Pricing and features verified from each vendor's public pricing page in July 2026, and quoted in the currency the vendor publishes. Both products change, so check the current page before you buy.
// Where Superhuman wins
Superhuman is the better buy for a specific person, and it is worth naming them. If you live in one Gmail or Outlook account, want the fastest keyboard-driven triage in email, value AI that drafts replies in your own voice, want native desktop and mobile apps, or need HubSpot and Salesforce built in, Superhuman does all of that and does it beautifully, and we do none of it: our AI reads and sorts your mail, it does not write it, and we have no mobile app. At roughly $25 to $30 per user per month it is priced as a premium tool for people whose whole job runs through one inbox. Pick Inboxes only if a true unified inbox across many providers, in a browser, is the specific thing you need.
FAQ
Questions people ask before switching
What is the best Superhuman alternative?
It depends on what pushed you off Superhuman. If you need a true unified inbox across more than Gmail and Outlook, from a browser, with AI sorting every message, Inboxes is the closest fit. If you want another fast AI client and you are staying on Gmail, Shortwave is the usual comparison, and Missive supports more providers for teams.
Was Superhuman acquired by Grammarly?
Yes. Grammarly acquired Superhuman in July 2025 and later renamed the combined company Superhuman, so the email client is now branded Superhuman Mail and sold alongside Grammarly writing tools. The client itself carried on as before, with more AI features layered in.
Does Superhuman work with Outlook?
Yes. Superhuman connects Gmail, Google Workspace, Outlook, and Microsoft 365. It does not support generic IMAP, so iCloud, Yahoo, Fastmail, or mail on your own domain cannot be added. Inboxes connects any IMAP mailbox, which is the main reach difference between the two.
Does Superhuman have a unified inbox?
Not a true one. Superhuman own help center describes running several accounts as a tab-based workaround rather than one merged inbox. Inboxes puts every connected account on one board with shared threads, shared search, and AI sorting across all of them at once.
Is Superhuman worth the price?
Superhuman is a premium client at roughly $25 to $30 per user per month, aimed at people who live in email and want the fastest keyboard-driven triage on a single Gmail or Outlook account. If your problem is instead many mailboxes across different providers, a unified inbox like Inboxes solves a different pain for a flat $29 a month.
Keep comparing
More on running every mailbox from one place
Put every mailbox on one sorted board
Connect your accounts over IMAP and let the AI categorize and de-spam your mail from the first message.