Best Open-Source Calendly Alternatives (2026)
6 self-hostable projects that directly address Calendly — without per-seat fees for multiple event types. The shortlist is manually checked for product fit before we compare self-host difficulty, deploy paths, maintenance, and licensing.
Answer first
Cal.com is the closest full Calendly replacement. Use Easy!Appointments for a service business with providers and bookable services, Zcal for a lighter scheduling page, or Rallly only when you need a group availability poll rather than a public booking link.
Editorial fit reviewed 2026-09-19 · repository activity and stars update separately
The important distinction is between public booking links, provider-and-service appointments, and group availability polls. This shortlist excludes ticketing platforms, CalDAV servers, job schedulers, and feedback tools because they cannot independently replace Calendly.
Choose by the job you need done
Direct Calendly replacement
Cal.comCal.com covers booking links, event types, team scheduling, integrations, and managed or self-hosted use.
Trade-off: It is the broadest option here, but that also makes self-hosting more involved than a small booking app.
Appointments for a service business
Easy!AppointmentsEasy!Appointments models providers, services, working hours, and customer bookings directly.
Trade-off: It is self-hosted rather than an official managed service and is less integration-heavy than Cal.com.
Find a time for a group
RalllyRallly is purpose-built for availability polls when several people must vote on a time.
Trade-off: It is adjacent to Calendly, not a replacement for external booking pages and round-robin scheduling.
Compare the 6 reviewed alternatives
Tap a column header to sort| Project | Deploy | Managed | License | ||||
|---|---|---|---|---|---|---|---|
 Cal.com TypeScript | 49k ★ | 3/5 Moderate | One-Click Docker +2 | AGPL-3.0 | today | Repo | |
 Zcal TypeScript | 1.2k ★ | 2/5 Simple | Docker Compose Manual | MIT | 7 months ago | Repo | |
| 4.5k ★ | 3/5 Moderate | Docker Docker Compose +1 | GPL-3.0 | 7 days ago | Repo | ||
 Tymeslot Elixir | 243 ★ | 3/5 Moderate | Docker Docker Compose +1 | Elastic-2.0 | today | Repo | |
 OpenSlots PHP | 400 ★ | 2/5 Simple | Manual Docker | MIT | 11 months ago | Repo | |
 Rallly TypeScript | 5.3k ★ | 3/5 Moderate | One-Click Docker +2 | AGPL-3.0 | today | Repo |
What to look for: Confirm the tool covers your booking model: one-on-one links and round-robin/team scheduling (Cal.com), group availability polls (Rallly), or fixed service appointments with providers (Easy!Appointments). Check calendar sync (Google/Microsoft/CalDAV), timezone handling, and whether the integrations and reminders you rely on are included rather than gated.
Before you migrate
- 1Verify two-way Google, Microsoft, or CalDAV sync with a real test calendar before inviting customers.
- 2Test timezone conversion, buffers, rescheduling, cancellation, reminders, and double-booking prevention.
- 3If you take payments or schedule teams, confirm payment, round-robin, routing, and workflow support explicitly.
The alternatives, reviewed
- #1
Cal.comSelf-host: ModerateScheduling infrastructure for everyone, the open-source Calendly alternative
49k TypeScript AGPL-3.0 todayHow it compares to Calendly
- Some enterprise features (e.g. SAML SSO, advanced admin/insights, certain platform features) are gated behind a commercial/EE license even when self-hosting.
- Self-hosting requires PostgreSQL plus configuring numerous environment variables and OAuth credentials for calendar integrations.
- The core code is AGPL-3.0, which imposes copyleft obligations on modified network deployments.
- Upgrades between major versions occasionally require manual database migration work.
- #2
ZcalSelf-host: SimpleBeautiful open-source scheduling page and availability management tool
1.2k TypeScript MIT 7 months agoHow it compares to Calendly
- Smaller calendar and integration ecosystem than Cal.com or Calendly.
- The self-hosted path has a smaller community and less operational documentation than Cal.com.
- Advanced enterprise administration and routing controls are less extensive than larger scheduling platforms.
- #3
Easy!AppointmentsSelf-host: ModerateSelf-hosted appointment scheduler for service businesses with provider and service management
4.5k PHP GPL-3.0 7 days agoHow it compares to Calendly
- No built-in payment collection at booking time, unlike Acuity/Calendly paid tiers.
- Calendar sync is limited to Google Calendar; no native Outlook/Office 365 or CalDAV support.
- The UI and admin experience feel dated compared to commercial products.
- Lacks advanced features like automated reminder workflows, packages/memberships, and intake form logic found in Acuity.
- #4
TymeslotSelf-host: ModerateElixir/Phoenix meeting scheduling platform you can self-host
243 Elixir Elastic-2.0 todayHow it compares to Calendly
- Younger and smaller project than Cal.com, with a more limited integration and app ecosystem.
- Licensed under the Elastic License 2.0, which is source-available rather than OSI-approved open source and restricts offering it as a competing managed service.
- Fewer calendar providers and payment options than mature commercial tools.
- Self-hosting requires an Elixir/OTP and PostgreSQL setup, which is less familiar to many ops teams.
- #5
OpenSlotsSelf-host: SimpleMinimalist appointment slot booking system with email confirmation
400 PHP MIT 11 months agoHow it compares to Calendly
- No recurring appointment or subscription booking support
- Email notifications only — no SMS or push
- No calendar sync (Google/Apple/Outlook)
- #6
RalllySelf-host: ModerateSelf-hosted scheduling polls to find the best time for a group to meet
5.3k TypeScript AGPL-3.0 todayHow it compares to Calendly
- Focused on group availability polling rather than one-on-one booking pages, so it does not replace Calendly's personal booking links.
- No direct calendar-availability checking or two-way calendar sync to auto-block busy times.
- No built-in payment collection or paid-appointment support.
- Requires PostgreSQL and SMTP configuration to self-host; not a single-binary deploy.
The verdict
Cal.com is the clear direct replacement for Calendly, matching it feature for feature with self-host or managed-cloud options and a huge community. Choose Rallly instead only if you mainly need group availability polls, or Easy!Appointments if you run a service business with fixed providers and bookable services.
Calendly alternatives — frequently asked questions
What is the closest open-source alternative to Calendly?
Cal.com is the closest direct replacement in this shortlist. It supports booking links and team scheduling, with both self-hosted and managed paths.
What is best for a service business with multiple providers?
Easy!Appointments is purpose-built around providers, services, working hours, and customer bookings. Verify calendar sync, reminders, payments, and intake requirements against your real workflow.
Is Rallly a Calendly replacement?
Not directly. Rallly is for group availability polls, where participants vote on possible times. It does not replace the full external booking-link and team-routing workflow.
Does self-hosting remove every scheduling cost?
It removes software seat fees, but you still pay for infrastructure, email delivery, backups, monitoring, and maintenance. One-click deployment is a setup shortcut, not a guarantee of free hosting.