Compare software

Right Inbox vs Mailbutler: catalog facts
Right Inbox	Mailbutler
Paid Paid plans required for full functionality.	Paid Subscription service with a 14-day free trial.
Browser extension	macOS, Browser extension
Combines send-later, reminders, and tracking in a single Gmail extension Used by a large base of professionals as a lightweight Gmail add-on	Works inside Apple Mail and Gmail Mail merge with scheduled sending
Works only within Gmail, not other webmail or desktop clients Full feature set requires a paid plan	Email tracking reveals recipient activity, which some recipients object to Requires a subscription after the trial
Browser extension	Downloadable app, Browser extension
Closed source	Closed source
License not stated	License not stated
Not stated if an account is needed	Account needed
Not stated if it works offline	Not stated if it works offline
Official website Full listing and sources Checked September 22, 2026	Official website Full listing and sources Checked September 23, 2026

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