Alternatives and competitors

Sites like Mozilla Thunderbird

The 20 closest email client software alternatives to Mozilla Thunderbird, ranked by what they actually offer, and the 10 technologies behind it.

Looking for an alternative to Mozilla Thunderbird? The closest matches are Mozilla, Firefox and Fastmail. We match sites by what they actually offer, from their homepages, Wikidata and a summary by Claude, in any language. Vote on each alternative and leave a short note to help the next person choose.

Neighbours
k = 20
Sites searched
4,032
Vector
384-d
Query
14 ms

01 · Entity

About Mozilla Thunderbird

Mozilla Thunderbird thunderbird.net

Wikidata: free email client and personal information manager

Top 10K · #4,294 English 10 technologies Crawled Nov 6, 2026
Visit Mozilla Thunderbird

Summary by Claude

Official site of Mozilla Thunderbird, a free and open-source email client with calendar, contacts, RSS reader, chat and newsgroup support, available for Windows, macOS, Linux and Android.

Who it’s for
Desktop and mobile email users, individuals and organizations
Business model
Donations

02 · Embedding space

Competitor map

Each alternative by how close its vector is to Mozilla Thunderbird’s (x) and how much traffic it gets, how much of the stack it shares, or where it sits in the embedding space itself (y). Lines split each axis at the median. Hover for the numbers, click to jump to it in the list.

similarity × popularity

ZoteroLinux kernelTutaSlideShareMailchimpmail.comNetBirdFastmailFirefoxMozilla

03 · Nearest neighbours

Alternatives to Mozilla Thunderbird

Thumbs up if it’s a real alternative to Mozilla Thunderbird, thumbs down if it isn’t.

Only in English

We can’t read thunderbird.net’s homepage (bot protection page), so it’s compared on what Wikidata and Wikipedia say about it.

  1. 01
    Mozilla mozilla.org Top 100 English

    Mozilla - Internet for people, not profit (US)

    We’re working to put control of the internet back in the hands of the people using it.

  2. 02
    Firefox firefox.com Top 1K English

    Firefox: The fast, private browser that keeps you safe — Firefox.com

    The independent browser that has your back. Firefox blocks trackers, has a free built-in VPN, puts you in control of AI, and never sells your personal data.

  3. 03
    Fastmail fastmail.com English

    Email and calendar made better | Fastmail

    Fast, private email hosting for you or your business. More productive, lightning fast, simple and built to save you time.

  4. 04
    NetBird netbird.io Top 10K English

    NetBird - Open Source Zero Trust Networking

    WireGuard®-based overlay network and Zero Trust Network Access in one platform for reliable and secure connectivity

  5. 05
    mail.com Top 10K English

    Free email accounts | Register today at mail.com

    Email how it is supposed to be: ✔ Free, simple and secure ✔ Manage multiple mail accounts in one place, from any device ✔ Sign up today!

  6. 06
    MailerLite mailerlite.com Top 10K English

    Create Email Marketing Your Audience Will Love - MailerLite

    Digital marketing tools to grow your audience faster and drive revenue smarter. Backed by 24/7 award-winning support. Check it out now!

  7. 07
    RustDesk rustdesk.com Top 10K English

    RustDesk: Open-Source Remote Desktop with Self-Hosted Server Solutions

    RustDesk is open-source remote desktop software for your own self-hosted server, a TeamViewer and AnyDesk alternative for Windows, macOS, Linux and Android.

  8. 08
    doxygen.org Top 10K English

    Doxygen homepage

    Source code documentation and analysis tool

  9. 09
    Mailchimp mailchimp.com Top 1K English

    Email & SMS Marketing Platform | Mailchimp

    Utilize real-time user behavior data and artificial intelligence to convert more customers. Easy to use, get started for free!

  10. 10
    SlideShare slideshare.net Top 1K English

    Client Challenge

    American hosting service, owned by Scribd, for professional content including presentations, infographics, documents, and videos

  11. 11
    Drupal drupal.org Top 10K English

    Client Challenge

    free and open-source web content management system

  12. 12
    Tuta tuta.com English

    Tuta: Turn ON privacy for free with secure emails, calendars & contacts | Tuta

    Tuta guarantees your data stays private for free & without ads. Quantum-resistant encryption makes Tuta the best secure technology solution to protect your privacy.

  13. 13
    Ghost ghost.org Top 10K English

    Ghost: The best open source blog & newsletter platform

    Beautiful, modern publishing with email newsletters and paid subscriptions built-in. Used by Platformer, 404Media, Lever News, Tangle, The Browser, and thousands more.

  14. 14
    Linux kernel kernel.org Top 10K English

    The Linux Kernel Archives

    Unix-like operating system kernel, basis for all Linux operating systems

  15. 15
    Zotero zotero.org Top 10K English

    Zotero | Your personal research assistant

    Zotero is a free, easy-to-use tool to help you collect, organize, cite, and share research.

  16. 16
    filezilla-project.org Top 10K English

    FileZilla - The free FTP solution

    FileZilla - The free FTP solution for both client and server. Filezilla is open source software distributed free of charge.

  17. 17
    MariaDB mariadb.org Top 10K English

    MariaDB Foundation - MariaDB.org

    database management system, relational, open source, community developed fork of MySQL

  18. 18
    utorrent.com Top 10K English

    µTorrent — Free Torrent Client for Windows, Mac & Android | Official Site

    Download µTorrent — the world's #1 BitTorrent client. Lightweight, fast, and free for Windows, Mac, and Android. Stream while you download with uTorrent Web.

  19. 19
    FreeBSD freebsd.org Top 10K English

    The FreeBSD Project

    free Unix-like operating system

  20. 20
    phpMyAdmin phpmyadmin.net Top 10K English

    phpMyAdmin

    database administration tool

Ranked by score: the cosine similarity of each site’s vector to thunderbird.net’s, less a small penalty for generic sites that are close to everything. Highlighted technologies are ones Mozilla Thunderbird uses too. Votes and comments come from visitors and don’t change the ranking.

04 · Fingerprints

Technology

What Mozilla Thunderbird is built with, and what its closest competitors use, from its homepage’s code and its DNS records.

Built with

Marketing automation
  • Mailchimp TXT v=spf1 include:%{i}._ip.%{h}._ehlo.%{d}._spf.vali.email include:spf.m…
Live chat & support
  • Zendesk TXT v=spf1 include:%{i}._ip.%{h}._ehlo.%{d}._spf.vali.email include:spf.m…
CDN
Email hosting
DNS hosting
SaaS tools (verified in DNS)
  • Apple Business TXT apple-domain-verification=pzjYlsoA8s7Ha71Q
  • Atlassian TXT atlassian-domain-verification=8xkMty0tOT0eog0PN17DvoBgD4NC/3/j/Tkx6tR…
  • Google Search Console TXT google-site-verification=96iXS_8P8qP6DhVQz3lTKDZqKDpvv2TIzJfiFmVBGXc
  • Notion TXT notion-domain-verification=CTJ2GxP5qpUZsOatCxmocIYuUHiXe1V8HTyXcPbZVyG

Stack changes

No changes yet. Each new crawl is compared with the last one, and what Mozilla Thunderbird adds or drops shows up here.

SimilarSiteSearch

Competitors by meaning, stacks from the source. Data from public homepages and DNS.

About our crawler