The Best Thunderbird AlternativesTop Email Clients and other similar apps like Thunderbird

Thunderbird is described as 'Free, open source, cross-platform e-mail, news and instant messaging client. The project strategy is modeled after Mozilla Firefox' and is a leading Email Client in the office & productivity category. There are more than 50 alternatives to Thunderbird for a variety of platforms, including Windows, Linux, Mac, Android and iPhone apps. The best Thunderbird alternative is K-9 Mail, which is both free and Open Source. Other great apps like Thunderbird are Claws Mail, Evolution, SeaMonkey and Microsoft Office Outlook.

Thunderbird alternatives are mainly Email Clients but may also be Calendar Apps or RSS Readers. Filter by these if you want a narrower list of alternatives or looking for a specific functionality of Thunderbird.

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Windows + Open Source

Thunderbird

2313

Free • Open Source
Email Client

Thunderbird is a free, open source, cross-platform e-mail, news and instant messaging client. The project strategy is...

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Thunderbird alternatives page was last updated

Mailbird
Sponsored
Paid • Proprietary
Email Client
Windows
65 Mailbird alternatives
Mailbird helps individuals and businesses manage emails in one place. This allows you to simplify your workflows. Therefore, spend more time on important tasks. Moreover, 9 in 10 of our customers describe our interface as “intuitive” and beautiful.
K-9 Mail
Is this is a good alternative?
Yes
No
Free • Open Source
Email Client
Android
Android Tablet
F-Droid
42 K-9 Mail alternatives
K-9 is an open source email client for Android with multi-folder sync, email signatures, Bcc-to-self, return-address configuration, keyboard shortcuts, Exchange Support, message flagging, IMAP deletes, saving attachments, configurable notifications and more.
- - K-9 Mail is the most popular Android & Android Tablet alternative to Thunderbird.
- - K-9 Mail is the most popular Open Source & free alternative to Thunderbird.
Suggest and vote on features
K-9 Mail Features
1. Ad-freeK-9 Mail doesn't contain any form of external advertising.
2. Multiple Account supportK-9 Mail support multiple accounts without the need to logout and login
3. Privacy focusedK-9 Mail is considered a privacy friendly alternative.
4. PGP EncryptionK-9 Mail supports PGP, an encryption system used for sending encrypted emails and files.
5. No TrackingK-9 Mail will not track you or use your personal data.
6. Unified inboxView e-mails (or similar) from all accounts in one unified view with K-9 Mail.
7. Works OfflineK-9 Mail can be used without the need to connect to the internet.
8. LightweightK-9 Mail consumes less device resources compared to similar apps.
9. End-to-End EncryptionK-9 Mail has E2E Encryption, for entire or parts of the app.
IMAP Support
Configurable
POP3 Support
One view multiple accounts
Contacts
Exchange
Dark Mode
Custom notifications
Header sorting
Comments about K-9 Mail as a Alternative to Thunderbird
Most users think K-9 Mail is a great Thunderbird alternative.
all • positive • negative relevance • date
kiminariyamamoto
Keeps the style of working with email as it should be, like we are used to from proper desktop Mail clients. It's unlike modern fancy clients with couple of buttons without even providing an option to view headers.
Top positive comment •
6

Guest
Been using for a long time on Android. Wish it was available for desktop and that's why this is no good when it comes to an alternative to Thunderbird. Otherwise, it is highly recommended for Android.
Top positive comment •
3

Guest
wrong platform. K-9 is for android, Thunderbird is not, so K9 is not a valid alternative for Thunderbird users
Top negative comment •
19

Frisk
This is an Android app. NOT an desktop app.
Negative comment •
1

ByteRanger
K-9 Mail is not for desktop operating systems, only Android. So you can't replace Thunderbird unless you are also replacing your desktop with a mobile device.
Negative comment •
0

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5 of 19 comments
Claws Mail
Is this is a good alternative?
Yes
No
Free • Open Source
Email Client
Calendar App
Windows
Linux
BSD
84 Claws Mail alternatives
Claws Mail is an email client (and news reader), based on GTK+, featuring

Quick response Graceful, and sophisticated interface Easy configuration, intuitive operation Abundant features Extensibility Robustness and stability.
- - Claws Mail is the most popular Windows & Linux alternative to Thunderbird.
Suggest and vote on features
Claws Mail Features
1. LightweightClaws Mail consumes less device resources compared to similar apps.
2. Extensible by Plugins/ExtensionsClaws Mail can be extended with add-ons, plugins and extensions.
3. Multiple Account supportClaws Mail support multiple accounts without the need to logout and login
4. No registration requiredYou can use most of the features in Claws Mail without registration.
5. Spam FilterClaws Mail can detect unsolicited, unwanted and virus-infected emails, calls, files, etc.
6. Privacy focusedClaws Mail is considered a privacy friendly alternative.
7. Works OfflineClaws Mail can be used without the need to connect to the internet.
8. Calendar IntegrationClaws Mail lets you sync your tasks and events with your calendar application.
9. PortableClaws Mail can be used from a USB stick or similar with no prior installation.
IMAP Support
Customizable
Ad-free
GPG Encryption
Import/Export OPML Feeds
End-to-End Encryption
Built-in RSS reader
Integrated Email Client
Multiple languages
Content Filtering
Comments about Claws Mail as a Alternative to Thunderbird
Most users think Claws Mail is a great Thunderbird alternative.
all • positive • negative relevance • date
Jonathan Dumont
Despite the style, Claws is super fast and allow you to programs it with Perl and Python which is great for marketing automation.
Top positive comment •
9

3psilon
It's a good, lightweight alternative, but the UI is clunky and it misses HTML message composing. You have been warned!
Top positive comment •
14

Guest
No HTML compose is the only reason I don't switch to it. We're not in 1980 anymore.
Top negative comment •
16

SViN
I think most people are using gmail accounts or outlook accounts to access their emails. Claws supports Oauth2 to access said accounts but the implementation, is a complete PAIN.

I can only realistically recommend something like this if your email provider is not forcing Oauth2.

I would like for the devs to get to work into making the experience of setting up an account with oauth as painless as thunderbird.
Comment •
0

Guest
very good alternative under linux. I can not say the same under windows since fancy plugin is very buggy.
Positive comment •
-1

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5 of 8 comments
Evolution
Is this is a good alternative?
Yes
No
Free • Open Source
Email Client
Calendar App
Linux
BSD
Flathub
S/MIME
GNOME
OpenPGP
82 Evolution alternatives
Evolution is a personal information management application that provides integrated mail, calendaring, address book and task list functionality. Evolution supports a wide range of industry standard data formats and network protocols for information exchange, with an emphasis on...
Suggest and vote on features
Evolution Features
1. Calendar IntegrationEvolution lets you sync your tasks and events with your calendar application.
2. Calendar ViewEvolution has a built-in calendar view to have a clear overview of your content over time.
3. Ad-freeEvolution doesn't contain any form of external advertising.
4. Multiple Account supportEvolution support multiple accounts without the need to logout and login
5. Sync with Google CalendarEvolution can be synchronized with Google Calendar
6. GPG EncryptionEvolution supports GPG (aka GnuPG) for encryption of things like emails, messages, files, etc.
7. RemindersEvolution allows you to set reminders for tasks, events or actions, based on parameters of time, place or condition.
8. Spam FilterEvolution can detect unsolicited, unwanted and virus-infected emails, calls, files, etc.
Contacts
CalDAV Support
Encrypted Email
CardDAV Support
Personal Information Manager (PIM)
IMAP Support
POP3 Support
Exchange
Integrated Spam Protection
Multiple languages
Comments about Evolution as a Alternative to Thunderbird
Most users think Evolution is a great Thunderbird alternative.
Michel Th.
I use both Thunderbird and Evolution, sometimes Claws-Mail. Evolution is the only one that can show the real "received" date in scams I have been receiving for months. In a today's scam Evolution shows "sent date" (falsified) 14-12-2019 and "received date" 30-01-2023 (evidently true). Thunderbird and Claws-Mail show 14-12-2019 in both columns.
Positive comment •
1

Guest
well, I use cinnamon desktop, Thunderbird does not display 24 hour format but AM/PM for starters. Also, I use the built-in acount manager and Thunderbird does not "talk" with that as well.. Evolution does sync my CALDAV and CARDDAV from this. Thunderbird needs plugins for this and these plugins also make Thunderbird unstable (lightning). Since I like to keep things "clean", Evolution is my software of choice ATM...
Positive comment •
1

Syntevo GmbH
Unfortunately, only available on Linux, not on Windows, not on MacOS. Otherwise promising.
Comment •
0

Guest
Has a nice Gui, works fast and has many options. Still some functions are not intuitive. Good alternative to Thunderbird
Positive comment •
0
SeaMonkey
Is this is a good alternative?
Yes
No
Free • Open Source
Web Browser
Mac
Windows
Linux
BSD
PortableApps.com
248 SeaMonkey alternatives
Web-browser, advanced e-mail, newsgroup and feed client, IRC chat, and HTML editing in one application. Itis built on the open source Mozilla Gecko engine, the same code which underlies Thunderbird and is the base for the Firefox browser.
- - SeaMonkey is the most popular Mac alternative to Thunderbird.
Suggest and vote on features
SeaMonkey Features
1. WYSIWYG SupportSeaMonkey integrates a WYSIWYG editor to edit the look and content of a document, page, or file.
2. LightweightSeaMonkey consumes less device resources compared to similar apps.
3. Privacy focusedSeaMonkey is considered a privacy friendly alternative.
4. PortableSeaMonkey can be used from a USB stick or similar with no prior installation.
5. Extensible by Plugins/ExtensionsSeaMonkey can be extended with add-ons, plugins and extensions.
6. Ad-freeSeaMonkey doesn't contain any form of external advertising.
Integrated Email Client
Built-in RSS reader
Add-ons
Built-in Download Manager
Customizable
Support for Firefox extensions
Modular System
Comments about SeaMonkey as a Alternative to Thunderbird
Some users think SeaMonkey is a great Thunderbird alternative, some don't.
Guest
SeaMonkey is both a WEB BROWSER and EMAIL CLIENT. It's the successor of Mozilla Application Suite or Netscape Communicator, resp. Further it includes also a news client program, an HTML editor (SeaMonkey Composer) and an IRC client (ChatZilla).
Positive comment •
21

Guest
Unfortunately doesn't support synchronization with CardDAV address books.
Negative comment •
0

apostolfaliagas
It has all of Thunderbird's features and many more.
Positive comment •
15

Guest
More of a web browser than an email client
Negative comment •
-9
Microsoft Office Outlook
Is this is a good alternative?
Yes
No
Paid • Proprietary
Email Client
Calendar App
Mac
Windows
Online
Android
iPhone
Android Tablet
Windows Phone
iPad
Apple Watch
Android Wear
141 Microsoft Office Outlook alternatives
Microsoft Outlook, part of the Microsoft 365 (Office) (not to be confused with Microsoft Outlook Express), is a personal information manager that lets you manage your e-mail, calendar, contacts, and tasks.
- - Microsoft Office Outlook is the most popular Web-based, iPhone & iPad alternative to Thunderbird.
- - Microsoft Office Outlook is the most popular commercial alternative to Thunderbird.
Suggest and vote on features
Microsoft Office Outlook Features
1. Email OrganizerMicrosoft Office Outlook allows you to take control of your inbox by filtering and control tools.
2. Calendar IntegrationMicrosoft Office Outlook lets you sync your tasks and events with your calendar application.
3. Support for @mentionsMicrosoft Office Outlook supports the use of mentions through @ to a particular user, who will be notified personally.
4. Calendar ViewMicrosoft Office Outlook has a built-in calendar view to have a clear overview of your content over time.
5. Support for AliasesMicrosoft Office Outlook supports aliases, so you can receive email without exposing your main email address
6. Unified inboxView e-mails (or similar) from all accounts in one unified view with Microsoft Office Outlook.
7. Multiple Account supportMicrosoft Office Outlook support multiple accounts without the need to logout and login
8. Works OfflineMicrosoft Office Outlook can be used without the need to connect to the internet.
9. Cloud SyncSync your data (notes, documents, bookmarks, etc.) across your different devices and to the cloud.
Exchange
Native application
Contacts
Built-in Calendar
Onenote Desktop Integration
Address book integration
Dropbox integration
Gmail integration
Office 365 integration
Onedrive integration
Comments about Microsoft Office Outlook as a Alternative to Thunderbird
Some users think Microsoft Office Outlook is a great Thunderbird alternative, some don't.
Eyji
As a Firefox user, I have tried to love Thunderbird but it just can't compete with Outlook, IMHO.
Top positive comment •
3

Guest
It works. Much less buggy. Better integration with Windows. Encryption/Signing.Works over remote desktop without losing pieces of itself. Search is crappier though.
Top positive comment •
2

LinuxDoge
Not open source, not privacy-focused, no Linux support
Top negative comment •
1

Guest
outlook is clumsy and bloated and does nothing well. tbird does one thing and well.
Negative comment •
3

Guest
Outlook do not support RSS
Negative comment •
0
FairEmail
Is this is a good alternative?
Yes
No
Freemium • Open Source
Email Client
Android
Android Tablet
F-Droid
44 FairEmail alternatives
FairEmail is a privacy-focused email client with a setup wizard that helpfully walks you through the steps to use it with any email provider. There are many privacy settings including encryption via OpenPGP and S/MIME and reformatted emails to avoid phishing.
Suggest and vote on features
FairEmail Features
1. Privacy focusedFairEmail is considered a privacy friendly alternative.
2. Multiple Account supportFairEmail support multiple accounts without the need to logout and login
3. PGP EncryptionFairEmail supports PGP, an encryption system used for sending encrypted emails and files.
4. Works OfflineFairEmail can be used without the need to connect to the internet.
5. No TrackingFairEmail will not track you or use your personal data.
6. Ad-freeFairEmail doesn't contain any form of external advertising.
7. Unified inboxView e-mails (or similar) from all accounts in one unified view with FairEmail.
8. Dark ModeFairEmail supports dark mode for comfortable usage in low light conditions.
9. LightweightFairEmail consumes less device resources compared to similar apps.
Customizable
Email Notifications
Extensive settings menu
IMAP Support
Notifications
S/MIME Support
Block Trackers
Calendar Integration
Comments about FairEmail as a Alternative to Thunderbird
Most users think FairEmail is a great Thunderbird alternative.
ByteRanger
While I do use FairEmail on my mobile devices and like it, it is not a valid alternative to Thunderbird which is for desktop platforms.
Negative comment •
0

Guest
wrong platform. FairEmail is not an alternative for Thunderbird users because it only runs on android. Thunderbird is for desktop operating systems only.
Negative comment •
-5