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Head-to-head · Email Apps

Mozilla Thunderbird vs GMX Mail

  • Updated Oct 2026
  • Both researched from official sources
  • 2 checks side by side
Higher score Mozilla Thunderbird #3 in Email Apps 9.2/10 Free plan Free plan✓ 1 of 3 features Visit Thunderbird
GMX Mail #8 in Email Apps 8.7/10 Free plan Free plan✓ 0 of 3 features Visit GMX Mail

Mozilla Thunderbird leads on 0 checks, GMX Mail on 0, and 2 are even. Who comes out ahead on the 2 yes/no, price and count checks where we have data for both products. The editor score weighs everything else too.

Our verdict

  • Highest scoreMozilla Thunderbird · 9.2/10
  • Free planboth
  • Most featuresMozilla Thunderbird · 1 of 3

Mozilla Thunderbird scores higher on our rubric for email apps: 9.2 against 8.7 out of 10; our editors rank them #3 and #8.

Mozilla Thunderbird is the better fit for free, open-source email across desktop and Android. GMX Mail is the better fit for free email with generous attachment and alias limits.

  • Mozilla Thunderbird fits best

    Free, open-source email across desktop and Android

  • GMX Mail fits best

    Free email with generous attachment and alias limits

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Side by side

Feature Mozilla Thunderbird 9.2/10 Visit ↗ GMX Mail 8.7/10 Visit ↗
At a glance
Editor score 9.2 8.7
Ranking #3 in Email Apps #8 in Email Apps
Best for Free, open-source email across desktop and Android Free email with generous attachment and alias limits
Pricing model Free Free
Starting price Free Free plan
Free plan ✓ ✓
Free trial — —
Deployment Desktop, Mobile Cloud, Mobile, Browser extension
Platforms Windows, macOS, Linux, Android Web, iOS, Android, Chrome extension
Features Mozilla Thunderbird 1/3 · GMX Mail 0/3
Unified inbox ✓ (best) Not checked yet
End-to-end encryption Not checked yet Not checked yet
Custom domains Not checked yet Not checked yet
Specs
Accounts supported Not checked yet Not checked yet
Platforms Not checked yet Not checked yet
Included storage Not checked yet Not checked yet
Our review
Pros
  • Manage multiple accounts in a unified inbox with search and message organization
  • Includes calendar, contacts, tasks, and offline local message storage
  • Open-source client supports OpenPGP encryption and add-ons
  • 65 GB mailbox storage and attachments up to 50 MB
  • Up to 10 aliases, plus spam and malware filtering
  • Includes PGP encryption, cloud storage, calendar, and Online Office
Cons
  • Scheduled sending requires the Send Later add-on
  • Support is through community resources and documentation
  • Desktop apps are limited to Windows, macOS, and Linux
  • The free service includes ads
  • Its broader tools are centered on the GMX ecosystem
  • PGP encryption may require more effort than basic email features
Our verdict

Mozilla Thunderbird is a free, open-source email client for individuals and organizations. Its desktop applications run on Windows, macOS, and Linux, and Thunderbird Mobile is available for Android. Multiple-account support and a unified…

Read the review →

GMX Mail is a free personal webmail service from 1&1 Mail & Media GmbH, for people who want a large mailbox and more than basic email. The free account includes 65 GB of mailbox storage, attachments up to 50 MB, and up to 10 email aliases.…

Read the review →
  1. Mozilla ThunderbirdEmail Apps 9.2Free plan
  2. GMX MailEmail Apps 8.7Free plan

Strengths and trade-offs

  • Mozilla Thunderbird — where it wins

    • Manage multiple accounts in a unified inbox with search and message organization
    • Includes calendar, contacts, tasks, and offline local message storage
    • Open-source client supports OpenPGP encryption and add-ons

    Where it doesn't

    • Scheduled sending requires the Send Later add-on
    • Support is through community resources and documentation
    • Desktop apps are limited to Windows, macOS, and Linux

  • GMX Mail — where it wins

    • 65 GB mailbox storage and attachments up to 50 MB
    • Up to 10 aliases, plus spam and malware filtering
    • Includes PGP encryption, cloud storage, calendar, and Online Office

    Where it doesn't

    • The free service includes ads
    • Its broader tools are centered on the GMX ecosystem
    • PGP encryption may require more effort than basic email features
  • Mozilla Thunderbird9.2/10 · Free plan

    A full-featured free email client for desktop and Android, with offline storage and an add-on ecosystem.

    Visit ThunderbirdFull verdict →
  • GMX Mail8.7/10 · Free plan

    A free personal email service with generous mailbox space and useful built-in tools.

    Visit GMX MailFull verdict →

More comparisons

All email apps comparisons → · Full ranking →

Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026

Last updated · How we research and update