Sites and apps similar to Thunderbird Appointment include Framadate, which is free and open source. Other options are Cal.com, Notion Calendar, Lunacal and Doodle. You're spoiled for choice with Appointment Schedulers like Thunderbird Appointment: we list more than 50 alternatives for Android, iPhone, self-hosting, iPad and Mac.
CalendHub syncs your calendars across Google Calendar and Outlook in real-time. See all your events in one unified view, avoid double-booking, and share scheduling links so others can book time with you. Privacy-first with full control over what gets synced.
AreYouFree is a free scheduling tool that combines group polls and personal booking pages in one platform. Create a poll with date or time options, share the link, and see when everyone's available — no account needed for anyone.
United Kingdom
Skej is a powerful AI assistant that handles all of your scheduling communications and booking tasks with both coworkers and external contacts. Skej is a conversational AI, working within all of your existing workflows like email, Slack, and MS Teams.
Kalendar is a free, open-source scheduling tool that offers premium features like custom branding, unlimited event types, and two-way calendar sync without a subscription. You can vibecode any feature you want using the founding.dev platform.
United States
Use your time efficiently by speaking to people when it is convenient for both of you, without scheduling a meeting. TAG allows you to make and receive calls only when you actually have the time to do so.
Sweden
EU
Create a shared event link, let participants mark free time without accounts, and use the resulting heatmap to find group overlap. The mobile-friendly tool handles local time zones and supports games, rehearsals, calls, study groups, and family events.
United States
Cal24h is a Swiss-hosted online appointment scheduling software for independents, practices, and teams.
Switzerland
Easy appointment scheduling, allowing users to share a link with available time slots, so invitees can quickly book a meeting, streamlining the process without back-and-forth communication.
United States
Designed for busy professionals who need fast, flexible scheduling. Aivee Booking uses AI and Smart Prompt Scheduling to instantly find the ideal time for your 1-on-1 meetings — all from a single, one-off link.
Singapore
