You keep two or three calendars and you are tired of double bookings. Keeper.sh and CalendarBridge both fix that by mirroring your busy time between them.
They split on price shape and on who holds your calendar. CalendarBridge charges per calendar and certifies its US cloud. Keeper.sh is $5 a month whatever your setup looks like, and is open source under AGPL-3.0, so the whole thing can run on a server you own.
Buy CalendarBridge if you are regulated
One decision settles this page before the rest of it. If your work needs a signed HIPAA business associate agreement, CalendarBridge offers one on its Premium and Pro plans and states it has been HIPAA compliant since 2022. Keeper.sh does not offer a BAA today.
The same goes for government work. CalendarBridge supports Microsoft 365 Government Community Cloud High, which Keeper.sh has no support for today.
Both of those are paperwork about somebody else's cloud, which is the trade. Buy the paperwork if a compliance officer is going to ask for it. Everything below is for the reader who is not in that position.
Will it connect the calendars you actually have?
CalendarBridge connects Google Calendar, Microsoft 365 for Business, Microsoft personal accounts on outlook.com, hotmail.com, live.com and msn.com, and iCloud. Microsoft 365 personal and family plans cannot be supported, because those plans do not expose a calendar over the internet.
For anything outside that list, their answer is an .ics link, which reads a calendar but cannot write to one.
Keeper.sh connects the same big three plus Fastmail, any CalDAV server and any public .ics link. On Nextcloud, Fastmail, Zimbra, Radicale or a server in your own house, Keeper.sh both reads and writes.
What happens when you change an event?
CalendarBridge is real-time from Google and Microsoft calendars, and their site says changes typically reach the other calendar within a minute or two. From iCloud and .ics calendars, they sync every 5 to 10 minutes.
Keeper.sh reads every connected calendar once a minute on both plans. A change then lands on the other calendar in about a minute on Pro, two at the outside. On free it is about fifteen minutes, thirty-one at the outside.
Free suits the person mirroring work into personal so evenings look blocked. Pro is the plan if a client is booking you while you are still on the call with them.
iCloud sets its own floor. Apple publishes no way for an outside tool to be told an event changed, so an iCloud calendar has to be checked on a schedule rather than watched.
What does it cost at eight calendars?
CalendarBridge charges monthly for a fixed number of calendars: Basic is $5 for 2, Premium is $10 for 5, and Pro is $40 for 8. Paying yearly takes 20% off, making those $4, $8 and $32 a month. Its unified calendar view is capped separately at 4, 12 and 24 calendars.
Keeper.sh is free for 2 linked accounts and 3 connections, with no cap on how many calendars each account carries. Pro is $5 a month, or $42 a year, and lifts both limits.
Picture a consultant carrying eight client calendars. That is $40 a month on CalendarBridge Pro and $5 on Keeper.sh Pro. Signing a ninth client moves one of those two numbers.
Keeper.sh does not price the symptom. However scattered your calendars get, unscattering them costs the same, which is the part of this a spreadsheet notices.
Where CalendarBridge fits better
You need an app on your phone. CalendarBridge ships apps on the Apple App Store, Google Play and the Microsoft Store. Keeper.sh runs in a browser, and once your connections exist it works without anyone opening it.
You need other people to book time with you. CalendarBridge includes up to 10 scheduling pages on every plan, built for people whose availability is spread across calendars. Keeper.sh does not ship booking links today, so it sits underneath whichever booking tool you use.
Procurement wants paperwork. CalendarBridge lists a verified SOC 2 Type 1 and offers a trust centre on request. Keeper.sh answers that from the other end: read the code, or keep the calendar on your own hardware so there is no third party to audit.
One admin sets up the whole team. CalendarBridge group plans let an admin manage everyone's connections on one bill, with no end-user involvement. Keeper.sh is set up one person at a time.
You want one screen showing every calendar. Their unified calendar app does exactly that. Keeper.sh gives you a calendar link instead, which you subscribe to from the calendar app you already use.
Where Keeper.sh fits better
Your calendar speaks CalDAV. Fastmail and Nextcloud calendars can be written to by Keeper.sh, and only read through a link by CalendarBridge.
Your setup is wide. Nine client calendars, four family ones and a shared team calendar all cost $5 a month. Nothing in the price depends on how many you have.
Your event details stay put. By default Keeper.sh copies a busy block labelled with the calendar's name, leaving the title, description and location on the original calendar. Pro can turn that off per calendar; the free plan keeps the private version and cannot change it.
You only want the next few months mirrored. Pro sets how far back and how far ahead each calendar copies, anywhere from one week to two years. An old job's calendar does not drag a decade of history across.
You want to skip the noise. Pro filters out all-day events, focus time and out-of-office blocks, so a week marked away does not black out your other calendar.
You want to automate it. Keeper.sh has a REST API and an MCP server with 14 tools for AI assistants, free at 25 calls a day and unmetered on Pro.
You want to read the code. Keeper.sh is AGPL-3.0, so nothing about how your events are handled is hidden from you.
Running Keeper.sh yourself
Run Keeper.sh yourself and every Pro feature is included at no cost. No licence key, no seat count, and nothing phoning home. You get unlimited accounts and connections, one-minute updates, event filters, and calendar contents that never leave your hardware.
Be honest with yourself about the work. You need a server, Postgres, Redis and a domain with TLS, plus your own Google and Microsoft apps for calendar access. That last part takes an afternoon and involves Google's verification process.
After that, upgrades, backups and uptime are yours. Docker Compose files and a standalone image keep the setup short. If that sounds like a second job, hosted Keeper.sh is $5 a month.
FAQ
Can I self-host CalendarBridge?
No, CalendarBridge is a hosted commercial product. Keeper.sh is AGPL-3.0 and runs on your own server with every Pro feature included.
Does Keeper.sh sync both directions?
Yes, as two connections. Each connection runs one way, so you create one in each direction to keep a pair of calendars feeding each other.
Which one should I pick?
Pick CalendarBridge for a HIPAA BAA, GCC High, mobile apps or scheduling pages. Pick Keeper.sh for CalDAV, a free tier, a flat price across a lot of calendars, or a copy you run yourself.
Where these facts come from
Everything above about CalendarBridge comes from their own public pages, checked on 11 August 2026. Everything about Keeper.sh comes from our code and our pricing. Prices and features change, so follow the links if a detail matters to your decision.
- CalendarBridge supported calendars, sync speeds, apps, SOC 2 Type 1, HIPAA and GCC High: calendarbridge.com
- CalendarBridge individual plans, prices, calendar counts and the HIPAA BAA tier: calendarbridge.com/pricing-individual
- CalendarBridge group plans and admin management: calendarbridge.com/pricing-group
- CalendarBridge scheduling pages: calendarbridge.com/scheduling-pages-for-people-with-multiple-calendars
- CalendarBridge security overview: calendarbridge.com/calendarbridge-security-overview
- Keeper.sh plans and limits: keeper.sh
- Keeper.sh code, licence and self-hosting guide: github.com/ridafkih/keeper.sh