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Spark vs Thunderbird

Published On January 14, 2025 - Last Modified On May 18, 2026

Spark vs Thunderbird Comparison Image

Meet the contenders

Whether you're a freelancer, small business owner, or corporate executive, there's an email app for you. We're here to help you decide.

Let's look at how these two email apps stack up against each other.

Spark Logo

Spark

Spark is an email client that transforms how you interact with your inbox, helping you eliminate email clutter, minimize distractions, and stay organized. With its Smart Inbox and Gatekeeper features, Spark aims to ease email management and prevent unwanted senders from taking over your inbox. Its Premium version offers advanced tools, such as AI-powered assistance and team collaboration.

Thunderbird Logo

Thunderbird

Thunderbird is a free, open-source, cross-platform email client that’s managed by a core staff and a community of volunteer developers. Although the app is already quite robust, there are optional add-ons that you can install to enhance its functionality. So, when it comes to cost-effective email client apps, you can’t go wrong with free—there are no separate paid versions.

Spark vs Thunderbird: A side-by-side comparison

Spark LogoSpark
Thunderbird LogoThunderbird

Operating system

Windows macOS iOS Android

WindowsmacOSLinuxAndroid

Versions

Free

Premium Individual

Premium Teams

Free

Price(s)

  • Free

  • Premium Individual: $4.99/month (billed annually)

  • Premium Teams: $6.99/month (billed annually)

  • Free

Notable features

  • Multi-account support

  • Unified inbox

  • Smart Inbox (categorizes/prioritizes messages)

  • Gatekeeper (screens and blocks emails)

  • AI-powered email assistant

  • Third-party app integrations

  • Natural-language searching

  • Bundle emails from preferred senders

  • Message pinning

  • Thread muting

  • Team collaboration tools

  • Multi-account support

  • Unified inbox

  • Extensive library of add-ons

  • End-to-end encryption (S/MIME and OpenPGP)

  • Junk mail filtering

  • Spam filtering

  • Phishing protection

  • Built-in chat

  • Built-in newsgroup and RSS reader

  • Tabbed email interface

  • Customizable user interface

  • Multi-language support (currently translated into 65 languages)