Kestrel vs Shortwave
Shortwave is an email app for Gmail and Google Workspace on the web, Mac, Windows, iPhone and Android, built around an AI assistant. It imports your mail and processes it for search, threading and AI, with its data stored in Google Cloud. Kestrel is a Mac app for Gmail and IMAP accounts. Its mail goes straight between your Mac and the provider, and its AI runs on your Mac or on your own Anthropic key.
At a glance
| Feature | Kestrel | Shortwave |
|---|---|---|
| Price | $20 a year, on up to 3 Macs | Free; Business $30 a seat a month |
| Platforms | Mac | Web, Mac, Windows, iPhone, Android |
| Mail accounts | Gmail and any IMAP account | Gmail and Google Workspace |
| Mail passes through | Your provider, and Anthropic if you add a key | Shortwave's servers, in Google Cloud |
| AI | On your Mac, or with your own Anthropic key | On every plan, mostly on its own hardware |
| Account needed | None, a license key | A Google account |
Where the AI runs
Shortwave's assistant works on mail Shortwave has imported. Shortwave says most of it runs on open-source models on its own hardware, with OpenAI and Anthropic also among its subprocessors.
Kestrel has no server that holds mail. Its AI runs on Apple Intelligence on your Mac, or on Claude with your own Anthropic API key, which sends the text a feature needs straight to Anthropic. Ask AI answers from the mail on your Mac.
Accounts
Shortwave needs a Gmail or Google Workspace account and brings other providers in by forwarding to it. Kestrel signs in to Gmail through a Google Cloud project you create, and to Proton Mail, Fastmail, iCloud or any IMAP server directly, with no Google account needed for those.
Which one to pick
Pick Kestrel if
- You want your mail kept off the app maker's servers.
- You use Proton Mail, Fastmail, iCloud or another IMAP account without a Gmail account.
- You want AI that runs on your Mac or on your own Anthropic key.
Pick Shortwave if
- You want a free plan with an AI assistant.
- You want the same app on Windows, the web, iPhone and Android. Kestrel is Mac only.
- You don't want to create a Google Cloud project.
The details
| Detail | Kestrel | Shortwave |
|---|---|---|
| Price | $20 a year for a license key, bought on account.laibe.cc. One key works on 3 Macs. The demo inbox, with made-up mail, is free to try. | A free plan that includes the AI assistant. Business costs $30, Premier $45 and Max $120 a seat a month, with a 14-day free trial. Shortwave imports 90 days of mail when you sign up, and upgrading imports your whole Gmail history. |
| Platforms | Mac only, on macOS 15 or later. A direct download, not on the Mac App Store, and it updates itself. | Apps for Mac, Windows, iPhone and Android, and the web, which installs as a progressive web app on other platforms. |
| Mail accounts | Gmail and Google Calendar, through a free Google Cloud project you create yourself in about five minutes. Any IMAP account for mail, with Proton Mail (through Proton Mail Bridge), Fastmail and iCloud Mail filled in for you. IMAP accounts have no calendar and keep recent mail only, such as the latest 400 in the inbox. | Sign-in needs a Gmail or Google Workspace account. Yahoo, iCloud and Fastmail come in by forwarding to Gmail, with an app password. Outlook.com is forwarding only, without sending from it, and Microsoft 365 and Exchange aren't supported. |
| Where your mail goes | Straight between your Mac and Google or your IMAP server. Kestrel's own servers see no mail. account.laibe.cc checks the license key, and kestrel.laibe.cc offers updates if you allow it. Sign-ins, mail passwords and API keys stay in the macOS keychain. Read statuses, team comments and booking pages need a team server you deploy to your own Cloudflare account. | Shortwave imports your mail and processes it for search, threading, labels and the AI assistant, and stores its data in Google Cloud. It can load images through its servers, to keep senders from tracking you. Mail goes out through Gmail's servers. |
| AI | Kestrel AI writes and rewrites drafts, summarizes threads, answers questions about your mail and labels new mail. It runs on Apple Intelligence on your Mac (macOS 26), or on Claude with your own Anthropic API key, which sends the text a feature needs to Anthropic. Auto Labels is on by default, and every part can be turned off. AI apps such as Claude Code can search, triage and draft through its MCP server, never send. | An AI assistant on every plan, with more usage, larger AI searches and more AI filters on higher plans. Shortwave says most of its AI runs on open-source models on hardware it controls, lists OpenAI and Anthropic among its subprocessors, and says your data never trains third-party models. |
| Keyboard | Every action has a key: E marks done, H sets a reminder, # trashes, / searches. ⌘K finds any action or folder by name and shows its key. A practice inbox teaches the first keys. | Single keys such as E for done, R to reply, C to compose and / to search, and a command palette. Shift ? lists every shortcut. |
| To sign up | No Kestrel account. You sign in to Google or your IMAP server, and add a license key. | A Gmail or Google Workspace account. |
Sources
Shortwave’s side was checked against these pages on . Write to [email protected] if something has changed.