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10 top picks · 1 audience ranking

Best open source booking and scheduling systems

The best open source booking and scheduling system is Cal.diy (MIT, 49,455 GitHub stars, Docker image). QloApps is the runner-up, and Rallly stands out for the most recent release (v4.16.3, October 2026).

This page also breaks the picks down by team size and use: Cal.diy leads for startups, small business and freelancers.

Updated · data from GitHub, refreshed daily

Top picks

  1. Rank 1:

    Cal.diy

    calcom/cal.diy

    Online appointment scheduling system.

    Active · last commit Oct 27, 2026

    Booking & SchedulingTypeScriptDocker

    Stands out for the most GitHub stars. Cal.diy has 49,455 GitHub stars, uses the MIT license, ships a Docker image and had 1,968 commits in the last year; it replaces Calendly.

  2. Rank 2:

    QloApps

    Qloapps/QloApps

    Customizable and intuitive web-based hotel reservation system and a booking engine.

    Active · last commit Oct 27, 2026

    Booking & SchedulingPHP

    QloApps has 14,450 GitHub stars, uses the OSL-3.0 license and had 1,487 commits in the last year.

  3. Rank 3:

    Rallly

    lukevella/rallly

    Create polls to vote on dates and times (alternative to Doodle).

    Active · last commit Oct 28, 2026

    Booking & SchedulingTypeScriptDocker

    Stands out for the most recent release (v4.16.3, October 2026). Rallly has 5,329 GitHub stars, uses the AGPL-3.0 license, ships a Docker image and had 1,711 commits in the last year; it replaces Calendly.

At a glance

Open source booking and scheduling systems compared

Ranked on GitHub stars, commits in the last year, Docker images, open-source licenses and recent commits across the 10 apps in the booking & scheduling category. Projects with fewer than 12 commits in the last 12 months rank below every more active project.

Top 10 picks compared, data as of Oct 28, 2026
AppStands out forLicenseGitHub starsCommits (12 mo)Last commitDocker image
Cal.diythe most GitHub starsMIT49,4551,968Oct 27, 2026Yes
QloApps–OSL-3.014,4501,487Oct 27, 2026No
Ralllythe most recent release (v4.16.3, October 2026)AGPL-3.05,3291,711Oct 28, 2026Yes
Hi.Eventsthe newest codebase (created October 2023)AGPL-3.0 with branding terms (Section 7)4,086346Oct 27, 2026Yes
Easy!Appointmentsthe longest track record (since 2014)GPL-3.04,462484Oct 26, 2026No
LibreBooking–GPL-3.0839709Oct 25, 2026Yes
Alf.io–GPL-3.01,62699Oct 27, 2026No
Seatsurfing–GPL-3.03151,233Oct 27, 2026Yes
OpenSlides–MIT66085Oct 20, 2026Yes
Chobble Tickets–AGPL-3.0362,688Oct 28, 2026Yes

1 of 2 · 10 picks

Top picks

10 of the 10 apps in the booking & scheduling category.

  1. 1

    Cal.diy

    Online appointment scheduling system.

    Stands out for the most GitHub stars. Cal.diy has 49,455 GitHub stars, uses the MIT license, ships a Docker image and had 1,968 commits in the last year; it replaces Calendly.

  2. 2

    QloApps

    Customizable and intuitive web-based hotel reservation system and a booking engine.

    QloApps has 14,450 GitHub stars, uses the OSL-3.0 license and had 1,487 commits in the last year.

  3. 3

    Rallly

    Create polls to vote on dates and times (alternative to Doodle).

    Stands out for the most recent release (v4.16.3, October 2026). Rallly has 5,329 GitHub stars, uses the AGPL-3.0 license, ships a Docker image and had 1,711 commits in the last year; it replaces Calendly.

  4. 4

    Hi.Events

    Event management and ticketing platform for conferences, concerts, and more. Offering customizable event pages and embeddable ticket widgets.

    Stands out for the newest codebase (created October 2023). Hi.Events has 4,086 GitHub stars, uses the AGPL-3.0 with branding terms (Section 7) license, ships a Docker image and had 346 commits in the last year.

  5. 5

    Easy!Appointments

    Allows your customers to book appointments with you via the web.

    Stands out for the longest track record (since 2014). Easy!Appointments has 4,462 GitHub stars, uses the GPL-3.0 license and had 484 commits in the last year; it replaces Calendly.

  6. 6

    LibreBooking

    Resource scheduling solution offering a flexible, mobile-friendly, and extensible interface for organizations to manage resource reservations.

    LibreBooking has 839 GitHub stars, uses the GPL-3.0 license, ships a Docker image and had 709 commits in the last year; it replaces Calendly.

  7. 7

    Alf.io

    Ticket reservation system.

    Alf.io has 1,626 GitHub stars, uses the GPL-3.0 license and had 99 commits in the last year.

  8. 8

    Seatsurfing

    Webbased app to book seats, desks and rooms for offices.

    Seatsurfing has 315 GitHub stars, uses the GPL-3.0 license, ships a Docker image and had 1,233 commits in the last year.

  9. 9

    OpenSlides

    Presentation and assembly system for managing and projecting agenda, motions and elections of an assembly.

    OpenSlides has 660 GitHub stars, uses the MIT license, ships a Docker image and had 85 commits in the last year.

  10. 10

    Chobble Tickets

    Event ticketing with QR check-in and encrypted attendee records. The complete product is AGPL-3.0 with no open core and no branding requirement, and it runs as an edge script without an always-on…

    Chobble Tickets has 36 GitHub stars, uses the AGPL-3.0 license, ships a Docker image and had 2,688 commits in the last year.

2 of 2 · 5 picks

Which open source booking and scheduling system is best for startups, small business and freelancers?

For startups, small business and freelancers, Cal.diy ranks first (MIT, 49,455 GitHub stars), followed by Rallly and QloApps. Ranked for startups, small business and freelancers (the same order for each) on GitHub stars, commits in the last year, Docker images, open-source licenses and recent commits.

  1. 1

    Cal.diy

    Online appointment scheduling system.

    Cal.diy has 49,455 GitHub stars, uses the MIT license, ships a Docker image and had 1,968 commits in the last year; it replaces Calendly. For startups it also scores on a Docker image, a permissive license (MIT), a project website and a commit in the last 90 days.

  2. 2

    Rallly

    Create polls to vote on dates and times (alternative to Doodle).

    Rallly has 5,329 GitHub stars, uses the AGPL-3.0 license, ships a Docker image and had 1,711 commits in the last year; it replaces Calendly. For startups it also scores on a Docker image, an open-source license, a project website and a commit in the last 90 days.

  3. 3

    QloApps

    Customizable and intuitive web-based hotel reservation system and a booking engine.

    QloApps has 14,450 GitHub stars, uses the OSL-3.0 license and had 1,487 commits in the last year. For startups it also scores on an open-source license, a project website and a commit in the last 90 days.

  4. 4

    Hi.Events

    Event management and ticketing platform for conferences, concerts, and more. Offering customizable event pages and embeddable ticket widgets.

    Hi.Events has 4,086 GitHub stars, uses the AGPL-3.0 with branding terms (Section 7) license, ships a Docker image and had 346 commits in the last year. For startups it also scores on a Docker image, an open-source license, a project website and a commit in the last 90 days.

  5. 5

    Easy!Appointments

    Allows your customers to book appointments with you via the web.

    Easy!Appointments has 4,462 GitHub stars, uses the GPL-3.0 license and had 484 commits in the last year; it replaces Calendly. For startups it also scores on an open-source license, a project website and a commit in the last 90 days.

FAQ

Questions and answers

Still curious? Email info@appsgit.com.

Is Cal.diy free?

Yes. Cal.diy is open-source software released under the MIT license, so you can self-host it at no cost. You only pay for the server it runs on, and some projects also offer an optional paid cloud plan.

Can I self-host these booking and scheduling systems with Docker?

Yes, 7 of the 10 picks. Cal.diy, Rallly and Hi.Events publish Docker images, so you can run them on a VPS or home server with Docker Compose. The others install from their own packages or source; follow each project's install guide.

Are all of these booking and scheduling systems open source?

All 10 apps on this list are open source. You can self-host and modify each one under its license.

Which of these booking and scheduling systems is the most actively developed?

Chobble Tickets, with 2,688 commits in the last 12 months and a latest release, v2026-10-03-091652, from October 2026. Activity is a good sign that bugs and security issues get fixed.

How is this list ranked?

Ranked on GitHub stars, commits in the last year, Docker images, open-source licenses and recent commits across the 10 apps in the booking & scheduling category. Projects with fewer than 12 commits in the last 12 months rank below every more active project.

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