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Best Open-Source Calendly Alternatives (2026)

20 self-hostable, open-source projects that replace Calendly — without per-seat fees for multiple event types. Each is scored for how hard it is to self-host, with one-click deploy options where they exist.

Calendly's pricing is per seat, and the features most people actually want, multiple event types, team scheduling, and integrations, sit on the paid tiers, so a few users quickly adds up. Self-hosting removes per-seat billing and keeps your booking data and customer contact details on your own infrastructure.

Close-up shot of a hand marking a date on a calendar with a pen, emphasizing planning and scheduling.
Photo by Towfiqu barbhuiya on Pexels

Our picks at a glance

Easiest to self-host
Cal.com

Difficulty 3/5 with a One-Click deploy option, the lowest-friction path among the Calendly-style schedulers here.

Most powerful
Cal.com

The most feature-complete option, with team scheduling, many event types, app integrations, and an API, explicitly built as the open-source Calendly.

Most active
Cal.com

At ~36,000 stars it has by far the most momentum and the largest contributor community of this group.

Best managed option
Cal.com

Offers an official managed cloud (managed:yes) so you can use it without self-hosting, with the same codebase available to self-host later.

Compare all 20 alternatives

ProjectDeployManagedLicense
Cal.com
TypeScript
47k ★
3/5
Moderate
One-Click
Docker
+2
AGPL-3.08 days agoRepo
Cal.diy
Nodejs
47k ★
3/5
Moderate
Docker
Docker Compose
+1
MIT8 days agoRepo
QloApps
PHP
14k ★
4/5
Involved
Docker
Manual
OSL-3.020 days agoRepo
Agenda
TypeScript
9.7k ★
3/5
Moderate
Manual
Docker
MIT9 days agoRepo
Rallly
TypeScript
5.2k ★
3/5
Moderate
One-Click
Docker
+2
AGPL-3.06 days agoRepo
Radicale
Python
4.9k ★
2/5
Easy
Docker
Manual
GPL-3.011 days agoRepo
Fider
Docker
4.4k ★
3/5
Moderate
Docker
Docker Compose
+1
MIT5 days agoRepo
Easy!Appointments
PHP
4.3k ★
3/5
Moderate
Docker
Docker Compose
+1
GPL-3.06 days agoRepo
Hi.Events
Docker
3.9k ★
3/5
Moderate
Docker
Docker Compose
+1
AGPL-3.04 days agoRepo
Baïkal
PHP
3.2k ★
3/5
Moderate
Docker
Manual
GPL-3.017 days agoRepo
pretix
Python
2.5k ★
3/5
Moderate
Docker
Docker Compose
+1
Apache-2.03 days agoRepo
Indico
Python
2.1k ★
4/5
Involved
Docker
Docker Compose
+1
MIT4 days agoRepo
SabreDAV
PHP
1.7k ★
5/5
Advanced
Manual
MIT15 days agoRepo
Bracket
Docker
1.7k ★
3/5
Moderate
Docker
Docker Compose
+1
AGPL-3.03 days agoRepo
Schej
Vue
1.7k ★
2/5
Easy
Docker Compose
Manual
MIT29 days agoRepo
Alf.io
Java
1.6k ★
4/5
Involved
Docker
Docker Compose
+1
GPL-3.04 days agoRepo
Zcal
TypeScript
1.2k ★
2/5
Easy
Docker Compose
Manual
MIT4 months agoRepo
Nextcloud Calendar
PHP
1.2k ★
2/5
Easy
Docker
Docker Compose
+1
AGPL-3.03 days agoRepo
OpenSlots
PHP
400 ★
2/5
Easy
Manual
Docker
MIT9 months agoRepo
Tymeslot
Elixir
159 ★
3/5
Moderate
Docker
Docker Compose
+1
Elastic-2.05 days agoRepo

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.

Head-to-head:Cal.com vs CalendlyCal.diy vs CalendlyQloApps vs CalendlyAgenda vs CalendlyRallly vs Calendly

The alternatives, reviewed

  1. #1
    Cal.com
    Self-host: Moderate

    Scheduling infrastructure for everyone, the open-source Calendly alternative

    47k TypeScript AGPL-3.0 8 days ago
    How 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.
    RepoDetails & deploy →
  2. #2
    Cal.diy
    Self-host: Moderate

    Open-source online appointment scheduling built on Cal.com

    47k Nodejs MIT 8 days ago
    How it compares to Calendly
    • Self-hosted setup requires configuring PostgreSQL, email/SMTP, and OAuth providers
    • Enterprise features (SAML SSO, workflows at scale, analytics) are cloud-only or require an enterprise license
    • Payment collection integrations need additional third-party setup
    • Admin UI for multi-tenant management is less polished than Calendly's hosted offering
    RepoDetails & deploy →
  3. #3
    QloApps
    Self-host: Involved

    Open-source hotel reservation and channel management system

    14k PHP OSL-3.0 20 days ago
    How it compares to Calendly
    • Scope is hotel-specific; not a general-purpose appointment scheduler
    • Channel manager integrations (OTA sync) are limited compared to commercial PMS solutions
    • Mobile app for guests/staff is absent out of the box
    • PrestaShop heritage makes theming and customisation non-trivial
    RepoDetails & deploy →
  4. #4
    Agenda
    Self-host: Moderate

    Node.js job scheduling library with persistent MongoDB-backed queue

    9.7k TypeScript MIT 9 days ago
    How it compares to Calendly
    • Library only — no UI for managing or viewing scheduled jobs without additional tooling
    • Requires MongoDB; not suitable for simple SQLite/Postgres-only stacks
    • No native support for distributed locking at high scale
    RepoDetails & deploy →
  5. #5
    Rallly
    Self-host: Moderate

    Self-hosted scheduling polls to find the best time for a group to meet

    5.2k TypeScript AGPL-3.0 6 days ago
    How 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.
    RepoDetails & deploy →
  6. #6
    Radicale
    Self-host: Easy

    Lightweight CalDAV and CardDAV server with minimal configuration

    4.9k Python GPL-3.0 11 days ago
    How it compares to Calendly
    • No web-based calendar UI; clients must use a CalDAV-compatible app (Thunderbird, Apple Calendar, etc.)
    • Not a booking/scheduling tool; no public booking pages or availability sharing like Calendly
    • Scaling beyond a handful of users is not a design goal
    • Lacks push notifications; relies on client polling
    RepoDetails & deploy →
  7. #7
    Fider
    Self-host: Moderate

    Open platform to collect, vote on, and prioritise user feedback

    4.4k Docker MIT 5 days ago
    How it compares to Calendly
    • categorySlug is 'scheduling' but Fider is a feedback/voting tool; replaces options are limited to scheduling slugs in the ref
    • No roadmap visualisation or timeline planning built in
    • Integrations with Jira, Linear, or Slack require custom webhooks
    • No in-app surveys or NPS measurement
    RepoDetails & deploy →
  8. #8
    Easy!Appointments
    Self-host: Moderate

    Self-hosted appointment scheduler for service businesses with provider and service management

    4.3k PHP GPL-3.0 6 days ago
    How 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.
    RepoDetails & deploy →
  9. #9
    Hi.Events
    Self-host: Moderate

    Self-hosted event management and ticketing for any scale

    3.9k Docker AGPL-3.0 4 days ago
    How it compares to Calendly
    • Payment gateway support is limited to Stripe; no PayPal or regional gateways out of the box
    • No recurring event / subscription ticketing support
    • Email marketing and attendee re-engagement tools are minimal
    • Mobile check-in app is not available; badge printing requires third-party tools
    RepoDetails & deploy →
  10. #10
    Baïkal
    Self-host: Moderate

    Lightweight CalDAV and CardDAV server based on sabre/dav

    3.2k PHP GPL-3.0 17 days ago
    How it compares to Calendly
    • No web-based calendar or scheduling UI for end users; requires a CalDAV client app
    • No public booking page or availability-sharing feature comparable to Calendly
    • Development activity has slowed; some sabre/dav edge cases may go unpatched
    • HTTPS and reverse-proxy setup is manual and not guided
    RepoDetails & deploy →
  11. #11
    pretix
    Self-host: Moderate

    Open-source ticket sales and event registration platform for any scale

    2.5k Python Apache-2.0 3 days ago
    How it compares to Calendly
    • Steeper setup curve than simple booking tools
    • No built-in one-on-one appointment scheduling workflow
    • Mobile app for organizers is Android/iOS only, not PWA
    RepoDetails & deploy →
  12. #12
    Indico
    Self-host: Involved

    CERN's open-source event and conference management platform

    2.1k Python MIT 4 days ago
    How it compares to Calendly
    • Overpowered for simple one-on-one appointment booking
    • Setup involves multiple services (Redis, PostgreSQL, Celery) and is complex
    • UI design is functional but dated compared to modern booking tools
    RepoDetails & deploy →
  13. #13
    SabreDAV
    Self-host: Advanced

    Open-source CardDAV, CalDAV, and WebDAV framework for PHP

    1.7k PHP MIT 15 days ago
    How it compares to Calendly
    • A developer framework, not an end-user product; requires significant custom PHP development
    • No admin UI, booking pages, or user-facing features out of the box
    • Documentation assumes solid PHP and WebDAV protocol knowledge
    • Not a drop-in replacement for any SaaS scheduling tool without substantial build effort
    RepoDetails & deploy →
  14. #14
    Bracket
    Self-host: Moderate

    Flexible self-hosted tournament management with live public rankings

    1.7k Docker AGPL-3.0 3 days ago
    How it compares to Calendly
    • No built-in calendar integration or iCal/Google Calendar sync for match schedules
    • Payment collection for entry fees is absent
    • Email or SMS notifications to participants are not supported out of the box
    • Limited reporting and export options compared to dedicated event-management SaaS
    RepoDetails & deploy →
  15. #15
    Schej
    Self-host: Easy

    When2meet-style group availability finder you can self-host

    1.7k Vue MIT 29 days ago
    How it compares to Calendly
    • No calendar integration — availability is marked manually
    • No booking confirmation or email reminders
    • Limited to group poll-style scheduling, not one-on-one booking pages
    RepoDetails & deploy →
  16. #16
    Alf.io
    Self-host: Involved

    Open-source ticket reservation platform for events of any size

    1.6k Java GPL-3.0 4 days ago
    How it compares to Calendly
    • No built-in recurring appointment booking (1:1 scheduling like Calendly)
    • Mobile app for attendees is not provided; check-in relies on a separate web view
    • Analytics and post-event reporting are basic compared to Eventbrite or Cvent
    • Initial Java/PostgreSQL setup is heavier than typical SaaS onboarding
    RepoDetails & deploy →
  17. #17
    Zcal
    Self-host: Easy

    Beautiful open-source scheduling page and availability management tool

    1.2k TypeScript MIT 4 months ago
    How it compares to Calendly
    • Fewer calendar integrations than Cal.com
    • No team scheduling or round-robin features
    • Limited workflow automation (no reminders or follow-ups)
    RepoDetails & deploy →
  18. #18
    Nextcloud Calendar
    Self-host: Easy

    Full-featured CalDAV calendar server built into Nextcloud with sharing and scheduling

    1.2k PHP AGPL-3.0 3 days ago
    How it compares to Calendly
    • No native public booking-page flow (requires a third-party plugin)
    • Video conferencing integration is limited compared to Calendly
    • Mobile app experience is less polished than hosted alternatives
    RepoDetails & deploy →
  19. #19
    OpenSlots
    Self-host: Easy

    Minimalist appointment slot booking system with email confirmation

    400 PHP MIT 9 months ago
    How it compares to Calendly
    • No recurring appointment or subscription booking support
    • Email notifications only — no SMS or push
    • No calendar sync (Google/Apple/Outlook)
    RepoDetails & deploy →
  20. #20
    Tymeslot
    Self-host: Moderate

    Elixir/Phoenix meeting scheduling platform you can self-host

    159 Elixir Elastic-2.0 5 days ago
    How 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.
    RepoDetails & 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.

Still deciding? Compare Cal.com vs Cal.diy side by side →

Calendly alternatives — frequently asked questions

What is the best open-source Calendly alternative?

Cal.com. It is explicitly positioned as the open-source Calendly alternative (AGPL-3.0, ~36,000 stars), supports multiple event types and team scheduling, and offers both self-hosting and a managed cloud.

Is there a free Calendly alternative I can self-host?

Yes. Cal.com, Rallly, Easy!Appointments, and Tymeslot are all open source and self-hostable. Cal.com is the closest one-to-one Calendly replacement; Easy!Appointments suits service-business booking.

Which Calendly alternative avoids per-seat pricing?

Any of the self-hosted options removes Calendly's per-seat fees because you run them yourself. Cal.com gives you unlimited event types when self-hosted, which is the main thing Calendly charges to unlock.

Which is easiest to self-host?

Cal.com is rated 3/5 and offers a One-Click deploy, making it the smoothest setup here. Rallly and Easy!Appointments are also 3/5 but lack the one-click path.

Can a group vote on the best meeting time like a poll?

Use Rallly for that. It is built specifically for group availability polls to find a time that works for everyone, which is a different use case from Calendly's fixed booking links.

Is there a managed-hosting option if I don't want servers?

Cal.com, Rallly, and Tymeslot all offer official managed hosting (managed:yes). Easy!Appointments is self-host only.

Keep exploring

All Scheduling & Booking →Self-hosted directory →Easiest to self-host →
Acuity Scheduling alternatives