Thunderbird Alternatives (2026): 10 Desktop Email Apps

Desktop email apps are having a quiet comeback. People who juggle several inboxes want one window, offline access and better search than a browser tab gives them.

Below are ten Thunderbird alternatives in no particular order, sorted alphabetically: open-source clients for Linux and Windows, polished apps for Mac and a few with team features. Each description comes from the app's own website, re-checked today. If your inbox is the real problem, my piece on getting AI to triage my email might help more than a new app.

Thunderbird alternatives at a glance

In the free plan column, Yes means the app's own site describes a free version, free plan or free open-source download. Some free versions limit the number of accounts.

Tool	Type	Good for	Free plan
Betterbird	Open-source email client	A Thunderbird-based fork with extra fixes	Yes
Claws Mail	Open-source email client	A very lightweight client	Yes
eM Client	Desktop email client	Email, calendar and contacts in one	Yes
Evolution	Open-source groupware	Email and calendars on Linux	Yes
Geary	Open-source email app	A clean, conversation-style inbox	Yes
KMail	Open-source email client	Email inside the KDE desktop	Yes
Mailbird	Desktop email client	Unified inbox with app integrations	Yes
Mailspring	Desktop email client	A modern open-source-based client	Yes
Spark	Email app	Smart inbox sorting	Yes
Sylpheed	Open-source email client	Simple, keyboard-friendly email	Yes

Ten desktop email apps to try instead of Thunderbird

Betterbird

Best for: Thunderbird users who want the same feel with additional features and fixes.

Claws Mail

Best for: People on older or slower computers who want a fast, simple email client.

eM Client

Best for: Windows and Mac users who want a polished all-in-one client.

Evolution

Best for: Linux users who want email, calendar and contacts in one GNOME app.

Geary

Best for: Linux users who want a simple inbox grouped into conversations.

KMail

Best for: KDE users who want a powerful client that fits their desktop.

Mailbird

Best for: Windows and Mac users who want a unified inbox with apps alongside.

Mailspring

Best for: People who want a modern client on Windows, Mac and Linux.

Spark

Best for: People who want an inbox that sorts important mail from newsletters and notifications.

Sylpheed

Best for: People who want a lightweight, no-frills client that's easy to use with the keyboard.

Thunderbird now has a mobile app, too

Here's something many people looking for an alternative haven't noticed. Thunderbird's own site now promotes Thunderbird Mobile, an open-source email app for Android available on Google Play and F-Droid, and describes it as free with no ads. If your reason for leaving was the lack of a phone app, check whether that's still true for you before you move. If you're on iPhone or want something different on the desktop, the list above gives you plenty of options.

Open source or polished commercial apps?

• Open-source clients are free, private and often lightweight, but some look dated.
• Commercial clients tend to look sleeker and add features such as snoozing, templates and integrations.
• Platform-specific apps fit Linux desktops especially well, so check which system you use.

Moving your mail across

1. Make a full backup of your current profile and local folders.
2. Add your accounts to the new app using IMAP so mail stays on the server.
3. Import any local folders, filters and address books the new app supports.
4. Recreate signatures and rules, since these rarely transfer.
5. Keep the old app installed for a few weeks in case you need something.

Search, filters and staying sane

Fast search is the feature people miss most when they switch. Test it with a real search, such as an invoice number or a client name from a while ago. Then set up a few filters for newsletters and notifications so your main inbox only shows mail that needs you. If you send a lot of marketing email, my round-up of email marketing stats shows why inbox habits matter on the reader's side too.

Privacy and what the app can see

Some modern email apps process your mail on their own servers to sort it or send reminders. That's convenient, but it means another company handles your messages. Open-source clients usually connect straight to your provider and keep mail on your computer. Read the privacy page of any app before you add a work account, especially if you handle client data.

Calendars and contacts

If you rely on Thunderbird's calendar, check how each alternative handles calendars and address books. Some sync calendars from your email provider, some need an add-on and some don't do calendars at all. Add a test event and a test contact before you commit, and make sure invitations from other people show up correctly.

Add-ons and extensions

If you've built your workflow around add-ons, check what each alternative supports before you switch. Some open-source clients share a lot with Thunderbird and can run similar extensions, while commercial apps usually offer built-in features or their own integrations instead. Make a short list of the add-ons you'd miss and find the equivalent in the new app before you move your main account.

It's worth asking whether you still need them, too. A few features you added years ago may now be built in.

Do you make a desktop email app? Tool makers can ask to be considered for a featured place on this list.

My plain advice on replacing Thunderbird

Be clear why you're leaving. If it's a missing phone app, check Thunderbird's own mobile app first. If it's the look or features, try one open-source client and one polished app with your real accounts for a week. Keep mail on the server with IMAP and you can change your mind any time.

Frequently asked questions

What's a good free alternative to Thunderbird?

Several apps here describe a free version or are free open-source software. The table shows what each site states.

Does Thunderbird have a mobile app?

Thunderbird's site promotes Thunderbird Mobile, an open-source email app for Android on Google Play and F-Droid.

Can I import my Thunderbird mail into another app?

Many apps can import local folders and address books. If your accounts use IMAP, your mail stays on the server anyway.

Which Thunderbird alternative is best for Linux?

Several open-source clients here are built for Linux desktops. Pick one that matches your desktop environment.

Are desktop email apps safe?

Most connect directly to your email provider. Check whether an app processes mail on its own servers before adding work accounts.

Will my filters and signatures move across?

Rarely. Plan to recreate filters, rules and signatures in the new app.

Do these apps handle calendars?

Some include calendars and contacts, some need an add-on and some don't. Test with a real invitation.

Will my Thunderbird add-ons work elsewhere?

Some forks support similar extensions, but most other apps don't. List the add-ons you rely on and look for equivalents first.