BlendedCal

The easiest and most customizable online calendar that you can access anywhere, anytime. Our shareable group calendars make office communication simple & secure. Plus it's easy to share with anyone! With Keep&Share calendars you can add images, colors, event tags, notes, reminders, notifications, attach files, to do lists, links, and more. You can share anything in your account with anyone on any device, whether they’re part of your team or not. This makes it easy to coordinate with clients, contractors, and anyone else you need for your business. Use custom colors and event tags to group events by team member, location, job, and more. Office managers can even use event tags to filter calendars for only the events that you, your field crews, or office staff want to see. Never miss another deadline — set up automatic email and text reminders for any event or task or your calendar. You can send reminders to yourself any anyone on your team.

Keeper.sh is a calendar syncing tool that helps you stop double-bookings, and increases your organizational capabilities: compatible with Google Calendar, Outlook, Microsoft 365, Apple Calendar, Fastmail, CalDAV and more. It syncs events in realtime, allows you to redact information so you only sync what you want, and helps you connect your calendars to your agents through a convenient MCP server and optional API. If you'd like to share your calendar with the privacy and calendar filters of your choice, you can also generate as many ICS links as you want. Keeper.sh has a convenient managed solution, but for privacy conscious users or technical hobbyists, it is open-source under AGPL-3.0, where you can get all premium features for free.