A Mac at work, Windows at home, Linux on the old laptop: if that is you, you want one mail app that runs on all three, so nothing changes when you switch. Four good clients do. Here they are, ranked. CitrusMail is ours, so weigh our view of it with that in mind.
Cross-platform email clients at a glance
| Price | Calendar | Contacts | Read receipts | AI help | |
|---|---|---|---|---|---|
| CitrusMail | Free | Yes, CalDAV | Yes, CardDAV | Free, built in | Your own key |
| Thunderbird | Free | Yes, with tasks | Yes | Not on its feature page | Not on its feature page |
| Betterbird | Free | From Thunderbird | From Thunderbird | Not on its home page | Not on its home page |
| Mailspring | Free, Pro $8 a month | Invitations; full calendar later | Contact profiles in Pro | Pro | Not on its pages |
1. CitrusMail: the same clean app on every computer
CitrusMail has downloads for Apple silicon and Intel Macs, Windows and Linux, and looks and works the same on each. Mail, calendar and contacts share one window. Sign in with your email and password and it finds the servers, for Gmail, iCloud, Outlook, Fastmail and any IMAP or POP3 mailbox.
It includes what other apps charge for or leave to add-ons: free read receipts (Delivered, Opened or Bounced in Sent), send later, rules, one-click unsubscribe, a signature for each mailbox, and AI with your own key for summaries, replies, questions across your mail and translation in both directions. Remote images stay blocked until you choose to show them.
It is open source under MIT and free. The honest limits: it is at version 0.1.0, it has no phone app or unified inbox yet, and it is an Electron app. If those are fine, download it here. We compare it with the old favourite in CitrusMail vs Thunderbird.
2. Thunderbird: the widest reach
Thunderbird runs on more computers than anything else here: 64-bit and 32-bit Windows and Linux, macOS, and even Windows 7 and 8.1. It has email, calendar, contacts and tasks, a unified inbox, a big add-on catalogue and an Android app. It is free and paid for by donations. The cost is complexity: there is a setting for almost everything, and finding it takes time.
3. Betterbird: Thunderbird, tuned
Betterbird takes Thunderbird and adds its own fixes and features. It offers a Windows installer and a portable version, a Linux archive and a Mac disk image for Intel and Apple silicon, the Mac one in English. It can share Thunderbird's profile, so switching back is easy.
4. Mailspring: polished, with a paid tier
Mailspring is free for everyday mail on Mac, Windows and Linux, with a unified inbox, fast search, translation, undo send and themes. Read receipts, link tracking, send later and templates come with Pro at $8 a month. A full calendar is, in its own words, coming later this year, so today it handles invitations only.
Which one is right for you
- You want mail, calendar and contacts in one modern window: CitrusMail
- You want read receipts and AI without paying monthly: CitrusMail
- You need add-ons, tasks or very old systems: Thunderbird or Betterbird
- You mostly want a tidy unified inbox: Mailspring or Thunderbird
Want only open source apps, including Linux-only ones like Evolution and KMail? See the best open source email clients, compared.
FAQs
What email client works on Mac, Windows and Linux?
CitrusMail, Thunderbird, Betterbird and Mailspring all offer their own downloads for all three.
Is there a free cross-platform email client with read receipts?
Yes. CitrusMail has read receipts built in at no cost. Mailspring has them in its $8 a month Pro plan.
Do my settings follow me between computers?
Your mail, folders, calendar and contacts live on your mail server, so every copy of CitrusMail shows the same ones. Signatures, rules and appearance are saved by the app on each computer, so you set those once per machine.
One app on every computer you use
CitrusMail is free on Mac, Windows and Linux. Install it on each, sign in, and the same mail, calendar and contacts are waiting.
- Apple silicon and Intel Macs
- Windows and Linux
- Free read receipts and your own AI