Keeper.sh is the OneCal alternative when you want a free plan, one price for every calendar, or copies that hide event details by default. OneCal has no free plan, and its Starter plan is $5 per user a month, billed yearly, for 2 calendars (OneCal pricing, checked 10 November 2026). Both products copy events between calendar accounts, and both connect Google Calendar, Outlook, iCloud and CalDAV servers.
Keeper.sh is a calendar sync service that copies events between Google Calendar, Outlook, iCloud, Fastmail and any CalDAV server, so every calendar shows you as busy at the same times. It is free for 2 calendar accounts and 3 connections, and Pro is $5 a month for unlimited calendars.
Keeper.sh and OneCal side by side
The table sets Keeper.sh's plans, calendars, update speeds and default copy settings beside OneCal's, and links each OneCal figure to the OneCal page it comes from (checked 10 November 2026).
| Keeper.sh | OneCal | |
|---|---|---|
| Free plan | 2 calendar accounts, 3 connections, no card (pricing) | None: a paid plan is needed after the trial (OneCal pricing) |
| Entry price | $5/month, or $45/year, for unlimited calendars | $5/user/month billed yearly ($60/year) for 2 calendars (OneCal pricing) |
| Calendars supported | Google Calendar, Outlook, iCloud, Fastmail, any CalDAV server; .ics links read-only | Google Calendar, Outlook, iCloud, any CalDAV server (OneCal) |
| Update speed, Google and Outlook | Within seconds on Pro; every 30 minutes on Free | "in real-time"; no figure published (OneCal) |
| Update speed, iCloud and CalDAV | Every minute on Pro; every 30 minutes on Free | Up to 10 minutes (OneCal) |
| What a copy shows by default | A busy block named after the source calendar; title, description and location hidden | Not published; each sync can exclude event titles |
| Trial | None needed: the Free plan has no time limit | 14 days, no card (OneCal pricing) |
What does each one cost?
OneCal bills per user. Billed yearly, Starter is $5 per user a month for 2 calendars, Essential is $10 for 5 calendars and Premium is $25 for 50 calendars, which comes to $60, $120 and $300 a year (OneCal pricing). Every plan starts with a 14-day trial that needs no card, and a paid plan is needed when the trial ends. An On Premise plan is available by enquiry.
On Keeper.sh, Free covers 2 calendar accounts and 3 connections. Pro is $5 a month or $45 a year for unlimited calendars, priced per person with no seats and no higher tier (pricing). A Keeper.sh account is one signed-in calendar service, however many calendars it holds. Each connection runs one way, so two-way sync is two connections. Sign-up needs no card: create a Keeper.sh account.
What does a copied event show?
Keeper.sh hides event details unless you turn them on. Each copy is a busy block named after the source calendar. The title, description and location are hidden by default, Pro can turn them back on per calendar, and guest lists are never copied. The calendar sync features page lists the other settings a connection has.
OneCal "allows customizing how events are replicated across your calendars", including excluding event titles (OneCal).
Which calendars does each one connect?
OneCal connects Google Calendar, Microsoft Outlook Calendar, Apple iCloud Calendar and "any calendar server that supports CalDAV" (OneCal). Its CalDAV integration page (checked 10 November 2026) names Fastmail, Nextcloud, Zoho Calendar, Radicale, Baïkal and Synology Calendar among others, and says a CalDAV calendar can be the source or destination of any sync on every plan.
Keeper.sh connects Google Calendar, Outlook, iCloud, Fastmail and any CalDAV server, and reads and writes all five. Google and Outlook connect by sign-in, iCloud by an app-specific password and Fastmail by an app password.
Keeper.sh takes an .ics link directly as a read-only source: events copy out of it and nothing writes back. In OneCal you subscribe to the link in Google Calendar or Outlook first, then select that calendar in OneCal (OneCal's ICS calendars help page, checked 10 November 2026).
How fast do changes arrive?
On Pro, Google and Outlook changes land within seconds, and iCloud, Fastmail and CalDAV changes land every minute. On Free, changes land every 30 minutes.
OneCal says "The calendars sync automatically, in real-time" and publishes no figure for Google and Outlook. For iCloud and CalDAV it says updates "take up to 10 minutes to reflect on the other calendars" (OneCal).
Can an assistant work with your calendars?
Keeper.sh runs an MCP server at https://www.keeper.sh/mcp with 27 tools, so an assistant such as Claude can read events, create, update and delete them, answer invitations, find free time and set up connections. It signs in through OAuth 2.1 with a consent screen and needs no API key. On Free, the MCP server and the REST API share 25 calls a day, and Pro has no daily cap. The Keeper.sh MCP server documentation lists every tool.
OneCal's MCP server (checked 10 November 2026) has 8 tools that list calendars, read busy intervals and events, and create, update, delete and respond to events.
What OneCal offers beyond calendar sync
- Scheduling links: individual and team booking links, which suit people who want booking pages and sync in one subscription.
- A calendar view: events from every connected calendar on one screen, where you can create, edit and delete them and RSVP.
- Phone apps: iOS and Android apps for managing syncs, links and calendars.
- An AI assistant: a built-in chat that creates events, finds free slots and re-runs syncs.
- Multi-way sync: OneCal says "you can sync one calendar to as many destinations as you want", with "Each sync is configured independently" (OneCal).
When Keeper.sh fits
- Free plan: two calendar accounts synced in both directions fit Keeper.sh's Free plan.
- Price: Keeper.sh Pro is $5 a month for one person, whatever the number of calendars; OneCal's plans cover 2, 5 and 50 calendars.
- Privacy: a new Keeper.sh connection starts with details hidden, so nothing needs configuring before a work calendar receives personal events.
- iCloud, Fastmail and CalDAV speed: changes on those calendars reach the other calendar every minute on Pro.
.icslinks: a timetable or schedule published as an.icslink goes straight into Keeper.sh as a source.
Step-by-step setup is in how to sync Fastmail with Google Calendar, how to sync Nextcloud with Google Calendar and how to sync Google Calendar and Outlook.
Common questions about Keeper.sh and OneCal
Is there a free alternative to OneCal?
Yes. Keeper.sh has a Free plan that needs no card. OneCal has a 14-day trial, after which a paid plan is needed.
Does OneCal support CalDAV and Fastmail?
Yes. OneCal connects any calendar server that supports CalDAV, including Fastmail and Nextcloud, on every plan. Keeper.sh also connects Fastmail and any CalDAV server.
How much does Keeper.sh cost compared with OneCal?
Keeper.sh Pro is $5 a month or $45 a year for one person with unlimited calendars. OneCal's plans are $5, $10 and $25 per user a month, billed yearly, for 2, 5 and 50 calendars.
Can Keeper.sh sync two calendars in both directions?
Yes. Two Keeper.sh connections, one in each direction, keep the pair matched, and the Free plan has room for both.
How quickly does an iCloud change reach the other calendar?
On Keeper.sh Pro, iCloud changes land every minute, and on Free they land every 30 minutes. OneCal says iCloud and CalDAV updates take up to 10 minutes.
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