Keeper.sh review: open-source calendar sync with privacy-first busy and free sharing, self-hosting and an AI-ready MCP server, pricing from free to 5 dollars.
Category
Calendar
Pricing
Freemium / Open Source, from Free (Pro plan $5/month)
Verified
Not yet
Last updated
July 18, 2026
Free PlanAPIOpen SourceFreemiumSelf-Hosted
Overview
Keeper.sh is an open-source calendar synchronization tool, unrelated to the password manager Keeper Security, built by developer Rida F'kih and released under the AGPL-3.0 license. It solves double-booking problems for people juggling multiple calendars across accounts and organizations.
The tool uses a pull-compare-push sync engine to keep busy and free time consistent across every connected calendar, with conflict reconciliation and race-condition prevention built in.
Key Features
Keeper.sh connects to Google Calendar and Outlook via OAuth, to FastMail and iCloud via CalDAV, and to any generic iCal or ICS feed in read-only mode, with flexible one-to-many or many-to-one mapping between calendars.
By default only busy and free time is shared, with event titles, descriptions and attendees stripped out unless a user opts in per calendar. An optional MCP server also gives AI agents read-only access to calendar data.
Pricing
A Free tier covers 2 accounts with 2 calendars each and syncs every 30 minutes, while the Pro tier at roughly $5 per month removes those limits and syncs every minute with priority support.
Keeper.sh can also be self-hosted via Docker, which includes all Pro-tier features at no cost beyond the user's own infrastructure.
Key Features
Pull-compare-push sync engine — Continuously reads, compares and pushes events across every connected calendar.
Privacy-first sharing — Shares only busy and free time by default, stripping titles and details unless opted in.
OAuth calendar support — Connects to Google Calendar and Microsoft Outlook with incremental sync.
CalDAV support — Connects to iCloud, FastMail and generic CalDAV servers.
iCal and ICS feeds — Reads external ICS feeds and generates a unique token-authenticated feed per user.
Flexible calendar mapping — Supports one-to-many and many-to-one sync configurations.
Real-time sync status — WebSocket-based status updates as calendars sync.
MCP server for AI agents — Optional OAuth 2.1 protected server giving AI assistants read-only calendar access.
Pros & Cons
Pros
Fully open source under AGPL-3.0 and self-hostable
Privacy-first default that strips event details before syncing
Built-in MCP server enables AI agents to query calendars directly
Affordable Pro tier with fast 1-minute sync intervals
Supports a wide range of calendar providers and protocols
Cons
Free tier is limited to 2 accounts and 2 calendars each
Built and maintained by a single developer, raising long-term support questions
Newer product with a smaller track record than established competitors
Self-hosting requires technical setup involving PostgreSQL, Redis and Docker
Free tier sync interval of 30 minutes is slow compared to the paid tier
Pricing
Free Free Free
Pro $5/month Monthly
Self-Hosted Free (self-hosted) Free forever
Frequently Asked Questions
Is Keeper.sh the same as Keeper Security?
No, Keeper.sh is an entirely different, unrelated product from the Keeper Security password manager.
Is Keeper.sh free?
Yes, a free tier exists with 2 accounts and 2 calendars each; the Pro tier costs roughly $5 per month.
Can I self-host Keeper.sh?
Yes, Keeper.sh can be self-hosted via Docker, including all Pro-tier features.
What calendars does Keeper.sh support?
Keeper.sh supports Google Calendar, Outlook, iCloud, FastMail, generic CalDAV servers and ICS feeds.
Does Keeper.sh share event details?
No, by default it only shares busy and free time; sharing titles or descriptions is opt-in per calendar.
Does Keeper.sh work with AI assistants?
Yes, an optional MCP server gives AI agents like Claude read-only access to calendar data.