Mozilla Thunderbird vs Roundcube

Mozilla Thunderbird9.4Visit Roundcube8.7Visit

Higher score Mozilla Thunderbird #1 in Email Clients 9.4/10 Free plan Free plan✓ 4 of 4 features Visit Thunderbird

vs

Roundcube #7 in Email Clients 8.7/10 Free plan Free plan✓ 0 of 4 features Visit Roundcube

• Mozilla Thunderbird fits best

  Users wanting a free, established open-source client

• Roundcube fits best

  Self-hosters wanting a dependable open-source webmail base

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Side by side

Feature	Mozilla Thunderbird 9.4/10 Visit ↗	Roundcube 8.7/10 Visit ↗
At a glance
Editor score	9.4	8.7
Ranking	#1 in Email Clients	#7 in Email Clients
Best for	Users wanting a free, established open-source client	Self-hosters wanting a dependable open-source webmail base
Pricing model	Free	Free
Starting price	Free	Free plan
Free plan	✓	✓
Free trial	—	—
Deployment	Desktop, Mobile	Self-hosted
Platforms	Windows, macOS, Linux, Android	Web
Support	Community, Docs	Community, Docs
Built for	Solo, Small business, Mid-market, Enterprise	Small business, Mid-market, Enterprise
Features Mozilla Thunderbird 4/4 · Roundcube 0/4
Unified inbox	✓ (best)	Not checked yet
Offline access	✓ (best)	Not checked yet
Scheduled sending	✓ (best)	Not checked yet
Calendar tools	✓ (best)	—
Specs
App coverage	Not checked yet	Web
Account limit	Not checked yet	Not checked yet
Our review
Pros	Unified inbox for managing multiple email accounts Calendar, contacts, and tasks included in the Free plan Offline access, local synchronization, and add-on extensibility	Free, open-source deployment on a web server IMAP folders, search, threading, identities, and address books Plug-in API with PGP encryption support
Cons	No verified integrations are listed Send Later is a queue, not timed scheduled delivery Mobile availability is limited to Android	No native mobile applications Calendar features are third-party additions Multiple-account support is a third-party addition
Our verdict	Mozilla Thunderbird is a free, open-source email client for personal and business use. It supports multiple email accounts, unified inboxes, message search and organization, calendars, contacts, and tasks. The desktop application is… Read the review →	Roundcube is a browser-based, multilingual IMAP email client for people and organizations that want to host their own webmail. Its application-like interface covers message composition and management, MIME and HTML messages, responsive… Read the review →

Strengths and trade-offs

• Mozilla Thunderbird — where it wins

  • Unified inbox for managing multiple email accounts
  • Calendar, contacts, and tasks included in the Free plan
  • Offline access, local synchronization, and add-on extensibility

  Where it doesn't

  • No verified integrations are listed
  • Send Later is a queue, not timed scheduled delivery
  • Mobile availability is limited to Android

• Roundcube — where it wins

  • Free, open-source deployment on a web server
  • IMAP folders, search, threading, identities, and address books
  • Plug-in API with PGP encryption support

  Where it doesn't

  • No native mobile applications
  • Calendar features are third-party additions
  • Multiple-account support is a third-party addition

• Mozilla Thunderbird9.4/10 · Free plan

  A capable free client for multi-account email, offline access, and desktop productivity tools.

  Visit ThunderbirdFull verdict →
• Roundcube8.7/10 · Free plan

  A focused, free webmail base for self-hosters who need core IMAP tools.

  Visit RoundcubeFull verdict →