MailRules vs Shortwave
Shortwave is an email app for Gmail with an AI assistant and AI filters. MailRules isn't an email app: it sorts mail on your server by rules you write, and you keep reading it wherever you do now.
| MailRules | Shortwave | |
|---|---|---|
| What it is | A sorting service. It files mail on the server; you read it in Apple Mail, Gmail, Outlook or any other app. | An email client you read and send mail in, with an AI assistant for search, writing and organising. |
| Mail providers | Any IMAP mailbox with an app password: iCloud, Fastmail, Yahoo, Zoho, Gmail or your own server. One-click Gmail and Outlook sign-in is planned for every cloud plan. | Gmail and Google Workspace. Other providers work by forwarding their mail to a Gmail account. Microsoft 365 and Exchange are not supported. |
| Plain-English rules | Type or dictate rules in your own words; mix them with exact conditions on sender, domain, subject, headers and attachments. | AI filters that act on new emails from a custom prompt: 3 on Business, 10 on Premier, 50 on Max. The Free and Pro plans have none. |
| Actions | Move, archive, trash, mark as junk, flag, mark read or unread. Nothing is permanently deleted; every action can be undone for 30 days. | Label, archive, delete, star and more. |
| Model choice | Jev or Clef decision models, Anthropic, any OpenAI-compatible API, or Ollama on your own machine. Set it for all rules or per rule. | Claude models from Haiku 4.5 to Opus 4.6. The highest level you can use depends on your plan. |
| Self-hosting | Yes. One Go binary with SQLite, open source under AGPL-3.0. | Hosted by Shortwave. |
| Price | Self-hosting is free; you pay your model provider. Hosted cloud is coming: Personal $5 a month, Pro $10 a month, Team $8 per seat. | Free plan. Pro $18, Business $30, Premier $45, Max $120 per seat a month; $14, $24, $36 or $100 billed yearly. |
An email app, or the one you have
Shortwave replaces your inbox app: you read, write and search mail in Shortwave. MailRules doesn’t have an inbox to read. It watches your mailbox with IMAP IDLE and files each new email on the server within seconds, so every app on every device sees the same folders. If you like Apple Mail or your phone’s mail app, you keep them.
Gmail only, or any IMAP inbox
Shortwave signs in with Gmail or Google Workspace. For iCloud, Fastmail, Yahoo or Zoho, its docs suggest forwarding that mail into a Gmail account. MailRules connects to those providers directly with an app password, and to any other IMAP server, including one you run.
How many rules, and which model
Shortwave’s AI filters come with the Business plan and up, capped at 3, 10 or 50 depending on the plan, and run on Claude models chosen by plan. In MailRules, senders you’ve corrected and exact conditions are decided without any model. The rest goes to a low-cost decision model you pick, or to Ollama on your own machine.
When Shortwave is the better pick
Pick Shortwave if you're on Gmail or Google Workspace and want a new email app, not just sorting. It gives you AI search across your mail, AI-written replies, summaries, bundles, todos and team features like shared threads and comments. MailRules has none of those. It works inside the app you already have and only files mail.
Sources
Checked on 8 October 2026.
Questions
Does Shortwave work with iCloud or Fastmail?
Only by forwarding that mail to a Gmail account, since Shortwave needs a Gmail or Google Workspace sign-in. MailRules connects to iCloud and Fastmail directly over IMAP.
Do I have to switch email apps to use MailRules?
No. MailRules moves mail on the server, so Apple Mail, Gmail, Outlook and your phone all see the same folders.
Is there a limit on how many rules I can write?
Shortwave's AI filters are capped by plan at 3, 10 or 50. None of the MailRules plans sets a rule limit.
Which AI model does MailRules use?
By default a low-cost decision model, with Claude Haiku 4.5 only for unsure cases. You can pick another provider, or run locally with Ollama.
Does MailRules write replies?
No. MailRules only sorts mail. Draft replies are planned as a paid cloud feature.