How Musubi compares.
An honest look at how Musubi stacks up against the apps that do a similar job — private shared calendars for the people you plan with. Google, Apple and Outlook aren’t rivals here; they’re the calendars these apps plug into, so they sit in the “what it can sync” rows below.
Feature by feature.
| Musubi | TimeTree | Cupla | Howbout | Self-hosted CalDAV | |
|---|---|---|---|---|---|
| iPhone + Android apps | Android nowiOS on TestFlight | Yes | Yes | Yes | Via CalDAV apps |
| Two-way sync with your existing calendars | |||||
| Google Calendar | Two-way | View only | Two-way | View only | No |
| Apple / iCloud | Two-way | No | Two-way | View only | No |
| Outlook / Microsoft 365 | Two-way | No | Two-way | View only | No |
| CalDAV (Nextcloud, Fastmail…) | Two-way | No | No | No | Native |
| Sharing, privacy & openness | |||||
| Private invite-only sharing | Yesowner / editor / viewer | Yes | Two people | Yes | Manual |
| Ad-free & no data sold | Yes | Ads on free tier | Yes | Freemium | Yes |
| Open source | Yes (MIT) | No | No | No | Yes |
| Self-hostable | Yes | No | No | No | Yes |
| Cost | |||||
| Price | Free (beta) | Free / $4.49·mo | Free / ~$4.99·mo | Free / Howbout+ | Free (self-host) |
Last checked July 2026. App features and pricing change and vary by region — check each vendor’s site for current details.
The alternatives, fairly.
TimeTree
A genuinely good free shared calendar with per-event chat and photos — a long-time favourite for couples and families. Two catches: it’s its own calendar rather than a two-way sync of the one you already use (it can display Google read-only), and the free tier shows ads. Musubi syncs your existing calendars both ways and stays ad-free.
Cupla
Polished and couples-focused, with real two-way sync to Google, Apple and Outlook plus shared lists — the closest to Musubi on sync. The differences: Cupla is built for two people, closed source, and gates features behind a subscription. Musubi works for any small group, adds owner/editor/viewer roles and CalDAV, and is open source and self-hostable.
Howbout
A big, well-made shared calendar for friends and groups (8M+ users), with a chat per plan. It pulls your Google, Apple and Outlook calendars in so nothing clashes — but that’s a read-in view for planning, not a two-way sync back to your calendars, and it’s closed source. Musubi writes changes back both ways and you can host it yourself.
Cozi
The long-standing family organiser — shared calendar plus shopping and to-do lists. Great for household logistics, but it’s its own calendar (no two-way Google sync), ad-supported on the now-limited free tier, and closed source. Musubi is the pick if you want your real calendars synced and no ads.
Self-hosted CalDAV (Nextcloud, Radicale)
Maximum control and fully open source — you already own the data. What they don’t give you is a polished sharing experience; they’re a protocol plus generic clients, and they don’t sync Google/Outlook for you. Musubi adds invite-only sharing, roles and a real app on top, syncs the big providers — and is itself self-hostable.
Where Musubi lands.
If you want the calendars you already use — Google, Apple, Outlook or CalDAV, in a browser or on Android — tied into one view you share only with a chosen few, without ads or a social layer, Musubi is built for exactly that. It’s open source and self-hostable if you’d rather run it yourself.
Start with one shared calendar for the people you plan with. Connect your existing accounts, invite your partner or family, and keep the rest of your calendars separate. Explore sharing and linked events →