Self-hosted alternatives to Calendly
One booking page is free; everything a real business needs is not.
Below are 10 open-source projects that cover the same ground, each scored 0–100 on how actively it is actually maintained — commit volume, release cadence and recent trend. 5 of the 10 are currently rated healthy or better. Ordering reflects that score, not sponsorship.
| Project | Health | Activity (11 mo) | Stars | Licence | Last release |
|---|---|---|---|---|---|
| Formbricks Experience Management Suite built on the largest open source survey stack worldwide. Gracefully gather feedbac | Thriving · 89 | 13k | AGPL-3.0 | 17 Sept 2026 | |
| Rallly Create polls to vote on dates and times (alternative to Doodle). | Thriving · 87 | 5.3k | AGPL-3.0 | 21 Sept 2026 | |
| Cal.diy Online appointment scheduling system. | Healthy · 75 | 49k | MIT | 1 Mar 2026 | |
| Hi.Events Event management and ticketing platform for conferences, concerts, and more. Offering customizable event pages | Healthy · 73 | 4k | AGPL-3.0 | 27 Aug 2026 | |
| Seatsurfing Webbased app to book seats, desks and rooms for offices. | Healthy · 68 | 316 | GPL-3.0 | 27 Sept 2026 | |
| QloApps Customizable and intuitive web-based hotel reservation system and a booking engine. | Steady · 67 | 14k | OSL-3.0 | 4 Jul 2025 | |
| LibreBooking Resource scheduling solution offering a flexible, mobile-friendly, and extensible interface for organizations | Steady · 67 | 817 | GPL-3.0 | 3 Aug 2026 | |
| Easy!Appointments Allows your customers to book appointments with you via the web. | Steady · 55 | 4.4k | GPL-3.0 | 7 Sept 2026 | |
| OpenSlides Presentation and assembly system for managing and projecting agenda, motions and elections of an assembly. | Steady · 53 | 647 | MIT | 23 Sept 2026 | |
| Alf.io Ticket reservation system. | Slowing · 49 | 1.6k | GPL-3.0 | 18 Sept 2026 |
How these were picked
Every project listed here is open source and can run entirely on hardware you control. We start from the categories that match Calendly's job — Booking and Scheduling, Polls and Events — then rank by health score so that a popular-but-abandoned project never appears above a smaller one that is actively shipping. The scoring method is documented in full.
The scores are recomputed from repository data on every rebuild, so this page reflects the state of these projects as of 1 Oct 2026 — not the day it was written.
Formbricks
Experience Management Suite built on the largest open source survey stack worldwide. Gracefully gather feedback at every step of the customer journey to know what your customers need.
Best fit: It is well-suited for product and development teams looking to self-host their own survey infrastructure using open-source tools.
Worth knowing: The software is licensed under the AGPL-3.0, which carries strict copyleft compliance obligations if you modify the code and provide it as a network service.
Rallly
Create polls to vote on dates and times (alternative to Doodle).
Best fit: It is well-suited for teams or social groups who need to coordinate event dates and wish to keep scheduling data on their own infrastructure.
Worth knowing: The AGPL-3.0 licence places strong copyleft obligations on your deployment if you modify and distribute the source code or offer it as a hosted service to external users.
Cal.diy
Online appointment scheduling system.
Best fit: It is well-suited for individuals or teams needing a self-hosted scheduling tool to replace commercial calendar and booking services.
Worth knowing: You should expect significant overlap with established scheduling alternatives, and managing a large Node.js codebase may introduce notable maintenance and dependency update overhead.
Hi.Events
Event management and ticketing platform for conferences, concerts, and more. Offering customizable event pages and embeddable ticket widgets.
Best fit: Organisers who want to self-host their own ticketing infrastructure and avoid paying commission fees to third-party event platforms.
Worth knowing: The software is distributed under the AGPL-3.0 licence, which places strict copyleft obligations on network services if you modify and host the code.
Seatsurfing
Webbased app to book seats, desks and rooms for offices.
Best fit: It is a suitable choice for small to medium organisations implementing hybrid working models who need a straightforward way to track desk and room occupancy.
Worth knowing: Adoption relies entirely on team compliance, and it lacks the extensive third-party enterprise calendar integrations typically found in commercial workspace suites.