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Shortwave vs Spark Mail: catalog facts
Shortwave	Spark Mail
Freemium Free to start with no credit card required, with paid options for more features.	Freemium Free for individuals; paid plans add AI features and team tools.
Windows, macOS, Android, iOS	Windows, macOS, Android, iOS
AI filters written in plain English Drafts replies that match your writing style	Automatic inbox categorization cuts down on manual sorting AI-drafted replies can speed up routine email responses
Built for Gmail accounts Relies on a hosted AI service that processes your mail	AI and team features are gated behind a paid plan Some categorization requires manual correction over time
Downloadable app, Hosted service	Downloadable app
Closed source	Closed source
License not stated	License not stated
Account needed	Not stated if an account is needed
Not stated if it works offline	Not stated if it works offline
Official website Full listing and sources Checked September 23, 2026	Official website Full listing and sources Checked September 22, 2026

Catalog facts only. Anything “not stated” is unconfirmed. Check full listings for details.