Open-source alternative to Calendly

I'll say this up front: Calendly isn't really a tool you leave to save money. Standard is $10 a seat a month on an annual plan, about £7.60. Five people pay around $600 a year, about £455, and the free plan covers a lot of solo users. It's also very good at what it does.

So why look elsewhere? Usually one of two reasons. You want bookings to live on your own website and in your own database. Or you have enough seats that a per-seat fee has started to add up. If that's you, there's one open-source tool I'd look at.

The sums do change with size. Thirty people on Standard would be $3,600 a year, about £2,727, and at that point a small server starts to look sensible.

Easy!Appointments

Easy!Appointments is a self-hosted booking app, and it has been going for years. It's built more for "book a service with one of our people" than for "find a time for a meeting".

• A booking page for customers, who don't have to sign up to use it. Put it on your own site by embedding it, or use the add-ons for WordPress, Joomla and Drupal.
• Services and providers. Set up what you offer, who offers it and their working plans. So a three-person clinic or salon can take bookings for each person.
• A shared team calendar for staff, with role-based accounts.
• Google Calendar sync, so existing commitments block out booking times.
• Email notifications when bookings are made.
• A REST API and webhooks, so bookings can flow into your other systems.
• Over 40 languages, and LDAP sign-in for staff if you need it.

It's light to run. You need a web server with PHP 8.2 or later, a MySQL database and a cron job for calendar sync. That's the sort of thing most business web hosting can manage, and Docker images are available too. All your records sit in your own database, and the software is free under GPL-3.0.

Here's the catch, and for many firms it's the big one. Scheduled reminder emails, SMS and online payments aren't in the free release. The project lists them as premium custom development. Calendly's Standard plan includes reminders and connects to Stripe and PayPal. If no-shows are costing you money, those reminders matter.

The project also offers managed hosting, at €20 a month billed annually, plus paid support, if you want its people to run it for you.

What about Cal.com?

If you've read older lists of Calendly alternatives, Cal.com will be at the top. It was the obvious answer for years. Not any more.

In April 2026 Cal.com moved its production code to a private repository, citing security. The open code continues as Cal.diy under the MIT licence. It's fully open source, but team features, organisations, workflows, insights and single sign-on have gone, and the project itself says it's "strictly recommended for personal, non-production use". The company points businesses to its paid product.

So Cal.diy may suit a hobbyist, but I can't recommend it for running a business, and that's why it isn't reviewed here.

Which one?

My pick is Easy!Appointments, for firms that take customer bookings and want them on their own site. It's simple, cheap to run and doesn't charge per person. The main drawback is that the free release has no scheduled reminders or online payments.

And the other realistic option is simply staying on Calendly. For a small team booking meetings, I'd say that's often the right answer.

• Customers booking services with your staff, on your own website: Easy!Appointments.
• Staff booking meetings, reminders matter, small team: stay with Calendly.

The UK angle

• Calendly is fine for most small firms. It's a US service, and that isn't a problem for ordinary business meetings. Just cover it in your privacy notice, as you would for any supplier.
• It matters more for sensitive bookings. Think about a clinic, a counsellor or a solicitor, where the booking itself says something personal about the customer. Having those records in your own database, on a server you choose, is a good reason to self-host.
• You own the booking history. Everything sits in your own MySQL database, so it can feed your CRM or be exported whenever you like.
• Keep reminders in mind. If you add your own, keep them to service messages rather than marketing.

Honest drawbacks

• No free reminders. The biggest gap, as above.
• No free payments. Taking deposits needs custom work.
• Less slick for meetings. It lacks Calendly's polish for finding a time between people.
• Fewer integrations. Google Calendar sync is the main one listed. I couldn't confirm Outlook or CalDAV support, so check before you commit if your team is on Microsoft 365.
• Small project. It's actively maintained, but it's not a big company. Plan for support coming from the community, or paying for it.
• Someone has to run it, including the cron job. If sync stops, double bookings start.

If you need reminders, deposits or bookings tied into your own system, the team at Dev Partners can build those for you, and the API makes that straightforward.

Sources

• Easy!Appointments
• Easy!Appointments on GitHub
• Calendly pricing
• Cal.com: why it went closed source
• Cal.diy on GitHub