Open source Calendly alternatives: Cal.com, Easy!Appointments and more

What does a Calendly alternative need to do?

Scheduling tools look simple and hide real complexity. They read your calendars for busy times, apply rules such as buffers and working hours, handle time zones, create events with video links and send reminders.

Before choosing, separate three jobs: a person offering meeting slots, a business booking customers into staff and services, and a group finding a date that suits everyone. Each points to a different tool.

Getting this right first saves you from bending a tool into a job it was not designed for.

Also count how many people will offer booking links. A single consultant needs far less than a sales team with routing rules and shared availability.

Which open source scheduling tools should you compare?

All of these are copyleft or have copyleft cores. That is normally fine for running your own booking page, but read the terms before modifying one and offering it to other businesses.

Cal.com: the full replacement

Cal.com covers what most people use Calendly for: public booking pages, event types with durations and buffers, sync with Google, Outlook and CalDAV calendars, video conferencing links, workflows for reminders and team features such as round-robin assignment.

It also exposes an API and embeddable booking widgets, which makes it a building block for products that need scheduling inside them. That is a strong reason developers pick it over a closed tool.

Some enterprise features are under a commercial licence rather than the AGPL core. Read the licence file and check which features your self-hosted build includes before planning around them.

Self-hosting Cal.com typically means Docker, Postgres, environment variables for each integration and a public HTTPS domain for calendar callbacks. The documentation covers each provider’s setup in detail.

For developers, the codebase is also a useful reference for how complex scheduling logic, such as availability across several calendars, can be structured.

Easy!Appointments and Rallly: narrower but simpler

Easy!Appointments is built for businesses that take bookings: salons, clinics, repair shops and consultancies. You define services, staff and working plans, and customers choose a service, a provider and a time. It runs on standard PHP hosting and can sync with Google Calendar.

Rallly solves a different problem: finding a date for a group. You propose several options, participants mark availability and you pick the winner. It replaces Doodle rather than Calendly.

Many organisations run one booking tool and one polling tool side by side.

Easy!Appointments also lets staff manage their own schedules and exceptions, and customers receive email confirmations. It is well suited to single-location businesses with a few providers.

Rallly keeps friction low: participants can respond without an account, which is exactly what you want when inviting people outside your organisation.

How to set up a booking page, and what does it cost?

Calendar OAuth setup is the step that takes longest, because providers require app registration and verified redirect addresses.

A small server is enough for a personal or team instance, plus an email sending service for notifications. The main cost is the setup time for calendar integrations and keeping the app updated.

For teams without anyone to maintain a server, the hosted versions of these projects remain an option, and your data model stays portable if you later self-host.

• Choose the tool by job: personal and team meetings, customer service bookings or group polls.
• Deploy with the project’s Docker setup or installer and connect a Postgres or MySQL database.
• Create OAuth apps for Google or Microsoft calendar access and add the credentials to the configuration.
• Configure SMTP so confirmations and reminders are delivered reliably.
• Set working hours, buffers and minimum notice before publishing any link.
• Book test meetings from another time zone and a phone to check the whole flow.

Common mistakes and where it breaks

Double bookings are the failure people remember. Check sync status regularly, and add a monitor that alerts when calendar connections fail.

Also check accessibility and mobile layout. Many invitees book from a phone, and a booking page that is hard to use on a small screen quietly loses meetings.

• Not handling time zones explicitly, so invitees see the wrong times.
• Forgetting that calendar provider app verification can take time for public use.
• Skipping SMTP setup and relying on defaults that land in spam.
• Allowing bookings with no minimum notice, leading to surprise meetings minutes away.
• Letting the calendar sync token expire unnoticed, which causes double bookings.
• Exposing admin pages without strong authentication.

How to choose the right option

Pick Cal.com when you want the closest match to Calendly, team scheduling or an API to embed booking in a product. Pick Easy!Appointments for a service business that books customers into staff schedules on simple hosting. Pick Rallly when the real task is agreeing a date with a group.

If bookings should trigger follow-up work, such as creating a CRM record or sending an intake form, connect the tool to an automation platform through webhooks. RepoLoot’s catalog tags business tools by difficulty, which helps when you are estimating the setup effort.

Test with real users before switching. A booking page is often a customer’s first contact with you, so broken reminders or confusing slots cost more than they seem.

Keep the old tool’s links redirecting for a while, since people bookmark and share them in email signatures.

How do they compare feature by feature?

This table summarises the capabilities most teams check first. Confirm specifics in current documentation, since scheduling tools add integrations often.

What can you build with an open source scheduler?

Scheduling often sits inside bigger products. Clinics, tutoring platforms, service marketplaces and consultancies use embedded booking so customers never leave their site.

With Cal.com’s API or webhooks you can create bookings from your own app, attach intake forms and push confirmed meetings into a CRM or billing system. Easy!Appointments fits similar flows for service businesses with simpler hosting needs.

Design the handoff carefully: who owns the customer record, which system sends reminders and what happens on cancellation.

Scheduling is harder to build than it looks, mainly because of recurring rules, time zones and calendar sync. Embedding an open source scheduler, or using its API, usually beats writing availability logic from scratch.

Keep your product as the source of truth for customers and let the scheduler own availability and events. Syncing through webhooks keeps the two systems loosely coupled.

Webhooks are the glue. Most integrations need only three events: booking created, rescheduled and cancelled. Handle those reliably and the rest follows.

Test the full lifecycle, including cancellation from the invitee’s side, before connecting billing. Refund logic tied to a missed webhook is a painful bug.

Frequently asked questions

Is Cal.com free to self-host?

Cal.com’s core is open source under AGPL-3.0 and can be self-hosted at no licence cost. Some enterprise features are covered by a separate commercial licence, so check the licence file and documentation to see what your self-hosted instance includes.

Can self-hosted schedulers sync with Google Calendar?

Yes. Cal.com supports Google, Outlook and CalDAV calendars, and Easy!Appointments can sync with Google Calendar. When self-hosting, you register your own OAuth app with the calendar provider and add its credentials to the scheduler’s configuration.

What is the best open source alternative for group scheduling?

Rallly is a strong choice for group date polls. Participants mark which proposed dates work for them, without creating accounts. It replaces Doodle-style polls, and it pairs well with a booking tool such as Cal.com for one-to-one meetings.

Which option works on shared PHP hosting?

Easy!Appointments runs on standard PHP and MySQL hosting, which makes it the easiest to deploy without Docker. Cal.com and Rallly are Node.js applications that need a server or platform able to run them, typically via Docker.