# Best open source booking and scheduling systems > The best open source booking and scheduling system is Cal.diy, with 48,880 GitHub stars, the MIT license and a Docker image; QloApps and Rallly are strong alternatives. This page also breaks the picks down by team size and use: Cal.diy leads for startups, small business and freelancers. The overall ranking weighs GitHub stars, commits in the last year, Docker images, open-source licenses and recent commits across the 9 apps in the booking & scheduling category of the appsgit catalog. ## Key facts | Fact | Value | |---|---| | Question | What is the best open source booking and scheduling system? | | Picks | 14 | | Top pick | Cal.diy (48,880 stars) | | Data as of | Oct 7, 2026 | | Canonical URL | https://appsgit.com/best/open-source-booking-systems | ## Top picks 9 of the 9 apps in the booking & scheduling category, ranked on GitHub stars, commits in the last year, Docker images, open-source licenses and recent commits. - [Cal.diy](https://appsgit.com/apps/cal-diy) (48,880 stars, MIT, TypeScript, Docker): Cal.diy has 48,880 GitHub stars, uses the MIT license, ships a Docker image and had 1,893 commits in the last year; it replaces Calendly. - [QloApps](https://appsgit.com/apps/qloapps) (14,409 stars, OSL-3.0, PHP): QloApps has 14,409 GitHub stars, uses the OSL-3.0 license and had 949 commits in the last year. - [Rallly](https://appsgit.com/apps/rallly) (5,285 stars, AGPL-3.0, TypeScript, Docker): Rallly has 5,285 GitHub stars, uses the AGPL-3.0 license, ships a Docker image and had 1,513 commits in the last year; it replaces Calendly. - [Hi.Events](https://appsgit.com/apps/hi-events) (4,050 stars, AGPL-3.0, PHP, Docker): Hi.Events has 4,050 GitHub stars, uses the AGPL-3.0 with branding terms (Section 7) license, ships a Docker image and had 277 commits in the last year; it replaces Eventbrite. - [Easy!Appointments](https://appsgit.com/apps/easy-appointments) (4,412 stars, GPL-3.0, PHP): Easy!Appointments has 4,412 GitHub stars, uses the GPL-3.0 license and had 171 commits in the last year; it replaces Calendly. - [LibreBooking](https://appsgit.com/apps/librebooking) (818 stars, GPL-3.0, PHP, Docker): LibreBooking has 818 GitHub stars, uses the GPL-3.0 license, ships a Docker image and had 637 commits in the last year; it replaces Calendly. - [Alf.io](https://appsgit.com/apps/alf-io) (1,616 stars, GPL-3.0, Java): Alf.io has 1,616 GitHub stars, uses the GPL-3.0 license and had 73 commits in the last year; it replaces Eventbrite. - [Seatsurfing](https://appsgit.com/apps/seatsurfing) (316 stars, GPL-3.0, Go, Docker): Seatsurfing has 316 GitHub stars, uses the GPL-3.0 license, ships a Docker image and had 1,137 commits in the last year. - [OpenSlides](https://appsgit.com/apps/openslides) (647 stars, MIT, Shell, Docker): OpenSlides has 647 GitHub stars, uses the MIT license, ships a Docker image and had 79 commits in the last year. ## Best for startups, small business and freelancers 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. - [Cal.diy](https://appsgit.com/apps/cal-diy) (48,880 stars, MIT, TypeScript, Docker): Cal.diy has 48,880 GitHub stars, uses the MIT license, ships a Docker image and had 1,893 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. - [Rallly](https://appsgit.com/apps/rallly) (5,285 stars, AGPL-3.0, TypeScript, Docker): Rallly has 5,285 GitHub stars, uses the AGPL-3.0 license, ships a Docker image and had 1,513 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. - [QloApps](https://appsgit.com/apps/qloapps) (14,409 stars, OSL-3.0, PHP): QloApps has 14,409 GitHub stars, uses the OSL-3.0 license and had 949 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. - [Hi.Events](https://appsgit.com/apps/hi-events) (4,050 stars, AGPL-3.0, PHP, Docker): Hi.Events has 4,050 GitHub stars, uses the AGPL-3.0 with branding terms (Section 7) license, ships a Docker image and had 277 commits in the last year; it replaces Eventbrite. For startups it also scores on a Docker image, an open-source license, a project website and a commit in the last 90 days. - [Easy!Appointments](https://appsgit.com/apps/easy-appointments) (4,412 stars, GPL-3.0, PHP): Easy!Appointments has 4,412 GitHub stars, uses the GPL-3.0 license and had 171 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. ## How this list was made - Candidates: the 9 apps in the booking & scheduling category. Archived projects and projects with no commit in the last two years are left out. - Base score: GitHub stars on a log scale plus commits in the last 12 months (log scale, capped at 1,000). - Bonus points for a published Docker image, an OSI-approved open-source license and a commit in the last 90 days. - Each "Best for" section re-ranks the same apps with that audience's profile (for example startups add points for permissive licenses, project websites and recent commits; small business for Docker images and deploy guides). - Source-available apps can rank, but they are labelled and never described as open source. ## FAQ ### 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. ### Which open source booking and scheduling system is best for a startup? Cal.diy ranks first for startups, with 48,880 GitHub stars, the MIT license and a Docker image; Rallly and QloApps follow. The startups ranking adds points for Docker images, permissive licenses, project websites and recent commits on top of stars and activity. ### Which open source booking and scheduling system is best for a small business? Cal.diy ranks first for small business, with 48,880 GitHub stars, the MIT license and a Docker image; Rallly and QloApps follow. The small business ranking adds points for Docker images, open-source licenses, project websites, recent commits and deploy guides on top of stars and activity. ### Can I self-host these booking and scheduling systems with Docker? Yes, 6 of the 9 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 9 apps on this list are open source. You can self-host and modify each one under its license. ## Related questions - [What is the best open source survey and event tool?](https://appsgit.com/best/open-source-survey-tools) - [What is the best open source e-commerce platform?](https://appsgit.com/best/open-source-ecommerce-platforms) - [What is the best open source budgeting app?](https://appsgit.com/best/open-source-budgeting-software) - [What is the best open source CMS?](https://appsgit.com/best/open-source-cms) - [What is the best open source team chat app?](https://appsgit.com/best/open-source-team-chat) - [What is the best open source file sharing app?](https://appsgit.com/best/open-source-file-sharing) - [What is the best open source low-code platform?](https://appsgit.com/best/open-source-low-code-platforms) - [What is the best open source API management tool?](https://appsgit.com/best/open-source-api-management) ## See also - [All booking & scheduling apps](https://appsgit.com/categories/booking-scheduling) - [All polls, surveys & events apps](https://appsgit.com/categories/polls-events) - [All groupware & calendars apps](https://appsgit.com/categories/groupware-calendars) - [Open-source alternatives to Calendly](https://appsgit.com/alternatives/calendly) - [Open-source alternatives to Eventbrite](https://appsgit.com/alternatives/eventbrite) - [Cal.diy vs Easy!Appointments](https://appsgit.com/compare/cal-diy-vs-easy-appointments) --- Canonical page: https://appsgit.com/best/open-source-booking-systems Source: appsgit (https://appsgit.com), the app store for github. Data from the GitHub API, refreshed nightly. Machine access: JSON API https://appsgit.com/api/v1/apps (OpenAPI: https://appsgit.com/openapi.json), MCP server https://mcp.appsgit.com/mcp, full index https://appsgit.com/llms-full.txt.