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.

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

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 vs Spark: A side-by-side comparison

	Thunderbird	Spark
Operating system	WindowsmacOSLinuxAndroid	Windows macOS iOS Android
Versions	Free	Free Premium Individual Premium Teams
Price(s)	Free	Free Premium Individual: $4.99/month (billed annually) Premium Teams: $6.99/month (billed annually)
Notable features	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)	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