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BusyContacts vs khard: catalog facts
BusyContacts	khard
Paid Costs $49.99 USD with a 14-day free trial; also available through Setapp.	Free Free and open source.
macOS	macOS, Linux, Command line
Direct sync with iCloud, Google, Exchange and CardDAV Tags, smart filters and per-contact activity history	Works on plain vCard files Fits terminal mail setups
macOS only One-time paid purchase after the trial	No built-in sync; needs a separate CardDAV tool Command line only
Downloadable app	Downloadable app
Closed source	Open source
License not stated	License not stated
No account needed	No account needed
Not stated if it works offline	Works offline
Official website Full listing and sources Checked October 2, 2026	Official website Full listing and sources Checked October 2, 2026

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