Mozilla Thunderbird vs Mailspring

Mozilla Thunderbird9.4Visit MMailspring8.6Visit

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

vs

M Mailspring #8 in Email Clients 8.6/10 Free plan Free plan✓ 3 of 4 features Visit Mailspring

• Mozilla Thunderbird fits best

  Users wanting a free, established open-source client

• Mailspring fits best

  Free desktop users wanting a capable open client

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Side by side

Feature	Mozilla Thunderbird 9.4/10 Visit ↗	MMailspring 8.6/10 Visit ↗
At a glance
Editor score	9.4	8.6
Ranking	#1 in Email Clients	#8 in Email Clients
Best for	Users wanting a free, established open-source client	Free desktop users wanting a capable open client
Pricing model	Free	Free plan + paid
Starting price	Free	—
Free plan	✓	✓
Free trial	—	—
Deployment	Desktop, Mobile	Desktop
Platforms	Windows, macOS, Linux, Android	Windows, macOS, Linux
Support	Community, Docs	Email, Community, Docs
Built for	Solo, Small business, Mid-market, Enterprise	Solo, Small business, Mid-market
Features Mozilla Thunderbird 4/4 · Mailspring 3/4
Unified inbox	✓	✓
Offline access	✓	✓
Scheduled sending	✓	✓
Calendar tools	✓ (best)	—
Specs
App coverage	Not checked yet	Desktop
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	Unified inbox and search across connected email accounts Works on macOS, Windows, and Linux with offline access Pro adds scheduling, tracking, reminders, templates, and snoozing
Cons	No verified integrations are listed Send Later is a queue, not timed scheduled delivery Mobile availability is limited to Android	Advanced productivity features require a paid Pro plan Focused on desktop rather than mobile email access Full-featured calendar support is still planned
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 →	Mailspring is a native desktop email client for people managing multiple accounts across macOS, Windows, or Linux. Its free plan covers core email functionality, multi-account support, and a unified inbox, while also providing advanced… 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

• Mailspring — where it wins

  • Unified inbox and search across connected email accounts
  • Works on macOS, Windows, and Linux with offline access
  • Pro adds scheduling, tracking, reminders, templates, and snoozing

  Where it doesn't

  • Advanced productivity features require a paid Pro plan
  • Focused on desktop rather than mobile email access
  • Full-featured calendar support is still planned

• Mozilla Thunderbird9.4/10 · Free plan

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

  Visit ThunderbirdFull verdict →
• MMailspring8.6/10 · Free plan

  A capable open desktop client with unified inboxes and optional productivity features.

  Visit MailspringFull verdict →