Open source alternatives to Calendly

What Calendly does

Calendly is a hosted scheduling service built around event types and booking links. A host connects Google, Outlook or Microsoft Office calendars so busy times are blocked, sets availability rules such as meeting hours, buffers, breaks and daily limits, and shares a link by email, on a social profile or embedded on a website. Invitees pick a time and receive confirmations, with reminders and follow-ups handled by automations on paid plans. Paid plans also take payments through Stripe and PayPal. The Teams plan adds round-robin and collective scheduling, routing forms for qualifying leads and CRM integrations such as HubSpot and Salesforce, and the Enterprise plan adds SSO, domain control and an audit log.

Why people look for an alternative

• Free plan limits. The free plan covers one event type and one calendar connection, for one-on-one meetings only.
• Per-seat pricing. Every user who hosts meetings needs a paid seat, so costs grow with the team.
• Team and security features sit on higher tiers. Round-robin, routing and centrally managed event types start at the Teams plan, and SAML single sign-on is an Enterprise feature or a paid add-on.
• Data location. Calendly’s help center says it stores user and invitee data in US-based data centers run by Google Cloud and AWS, and relies on Standard Contractual Clauses for transfers from the EEA and UK. The names, emails and answers of the people who book with you therefore sit with a US provider.
• No self-hosted option. Calendly runs only as a hosted service.

What to compare in an alternative

1. Calendars. Google and Microsoft 365 are common; CalDAV support decides whether you can use a self-hosted or standards-based calendar server.
2. Event type options. Buffers, minimum notice, booking windows, custom questions, approval of requests, and group or seated events.
3. Video links. Which conferencing providers can create a meeting automatically for each booking.
4. Team scheduling. Round-robin, collective events and routing forms. This is the biggest gap in open source tools, so check it first if you schedule for a team.
5. Embeds, payments, webhooks and API if bookings feed into a website, a CRM or an automation tool.
6. Self-hosting effort and maintenance. The services the tool needs, the OAuth apps you must register with Google, Microsoft or Zoom, outbound email, and who maintains the project.

Which one to choose

For the closest match to an individual Calendly account, Cal.diy has the broadest feature set: event types, many calendar and video integrations, Stripe and PayPal payments, embeds, webhooks and an API, all under MIT. It is the open source continuation of Cal.com, which went closed source in April 2026, and it has lost Cal.com’s team features; its maintainers recommend it for personal, non-production use. Tymeslot is the lighter option, a single Docker container with strong CalDAV support, embeds, payments and a managed cloud from its developers, under AGPL-3.0 since mid-2026.

Thunderbird Appointment suits people whose calendar is on a CalDAV server and who want an approval step before bookings are confirmed; its hosted version comes with a Thundermail subscription. CloudMeet is a minimal personal booking page that deploys to Cloudflare’s serverless platform, with Google and Outlook calendars and Meet or Teams links. If you run a business that books customers with staff and services rather than meetings with a person, Easy!Appointments is the better fit.

None of these replaces Calendly’s round-robin, routing forms and team analytics, so teams that depend on them should test carefully before switching. To find a date with a group rather than take bookings, see the Doodle alternatives and the scheduling guide.