Shortwave vs Superhuman, which AI email client wins?

Short answer

Pick Shortwave if your problem is finding and understanding mail, pick Superhuman if your problem is getting through it. Shortwave's AI search over your whole Gmail archive is the best in the category and nothing else comes close. Superhuman's keyboard model is the fastest way to empty an inbox and it is the only one of the two that works with Microsoft 365. Both process your mail in the United States, both start above 20 EUR per user and month, and neither offers EU data residency.

Price compared

Converted at 1 USD = 0.92 EUR. Superhuman is cheaper on the published entry price, but the comparison is not clean: Shortwave publishes monthly rates and Superhuman publishes annual ones with a stated 17 percent annual saving. If you want a monthly commitment from Superhuman you cannot read the price without running the page's JavaScript, which is a small thing that tells you something about both companies.

Where is your mail processed?

This is the criterion most buyers in Europe check first, and here the two vendors differ less in substance than in paperwork.

Superhuman is the more transparent of the two. It publishes a data privacy addendum and an itemised sub-processor list with a location for every entry, and the transfer mechanism is named: Data Privacy Framework plus EU and UK standard contractual clauses. Shortwave's security page names only four companies in prose and tells organisations that require GDPR compliance to contact the team, which in practice means a sales conversation before a legal review.

Shortwave makes one claim Superhuman does not: that the vast majority of its AI workloads run on open source models on hardware it controls, with OpenAI, Anthropic and Pinecone as the only outside AI services. If accurate, that is a materially shorter processing chain than Superhuman's nine named model and inference providers. Neither company offers a European region, so for a buyer whose rule is that the mail body must stay inside the EU, both fail at the first question. Our guide to checking an AI email vendor against the GDPR sets out what to ask for in writing.

Which has the better AI?

Shortwave, clearly, and it is the single strongest reason to choose it. It indexes your entire Gmail history and answers questions about it rather than matching keywords, so "what did the landlord say about the renewal date" returns an answer and the thread it came from. AI threads let you keep asking inside a conversation. This is a capability, not a feature, and after a few years of accumulated mail it changes what the archive is for.

Superhuman's AI writes, summarises, and adjusts tone, and it does those competently. It also has an auto-labelling and triage layer. But the AI is an accelerant on an already fast client rather than the product itself. If you removed the AI from Superhuman you would still have the best keyboard mail client in the world. If you removed it from Shortwave you would have an ordinary Gmail front end.

Which is faster to use?

Superhuman, and the margin is wide. Every action has a shortcut, the command palette reaches everything, split inbox divides the queue before you touch it, and the whole client is engineered around perceived latency. People who process several hundred messages a day genuinely get faster on it, and that is a measurable return on 23 EUR a month. The cost is a learning curve of a week or two, and a product opinion you have to accept.

Shortwave is a normal modern mail client in terms of interaction. Good, not remarkable. You will not get faster at triage by switching to it, you will get better at retrieval.

Mailbox support decides more purchases than either company admits

Shortwave works with Gmail and Google Workspace only, and says so plainly: Microsoft 365 and Exchange accounts are not supported. Yahoo, iCloud, Fastmail and Zoho work only by routing through a Gmail account with an app password, and Outlook.com and ProtonMail are forwarding only, with no ability to send from the address.

Superhuman supports Gmail, Google Workspace and Microsoft 365 hosted accounts. Neither supports generic IMAP, so if you host mail with a European provider such as Infomaniak, Mailbox.org or your own server, both are out and you should look at the clients in our ranking of AI email clients that take plain IMAP.

So which should you buy?

Buy Shortwave if your mail is in Google Workspace, you have years of history, and the recurring problem is that nobody can find anything. Buy Superhuman if you are a high-volume sender, you are willing to learn shortcuts, or you are on Microsoft 365, in which case Shortwave is not an option at all.

Buy neither if your organisation requires that mail content stays in the EU. Both are US-hosted and neither will change that for a single customer. In that situation the question is not Shortwave or Superhuman, it is which European or on-device alternative you can live with, and what you give up in AI quality to get there. That trade is real, and anyone who tells you it is free is selling something.