Cal.diy

The free alternative toCalendly,Cal.com

🔴 Advanced⏱️ ~45 min to installYou save €12/mo

Cal.diy is your booking page: you send a link, the person picks a slot from your real availability, the meeting lands in your calendar and the video link is created automatically. It is the community edition of Cal.com: the same engine, all commercial code removed, and a fully open license. The difference with Calendly: no caps (event types, calendars, integrations, everything included), your link lives on YOUR domain, and your calendar data stays on your server. It is the only tool in this library I use in production for my own business, every day.

48.5kView on GitHub ↗

Versus Calendly: the match

Price
Cal.diy
€0, forever
Calendly
€12/mo per user
Event types
Cal.diy
Unlimited (15 min, 30 min, 1 h…)
Calendly
One on the free plan
Your link
Cal.diy
book.yourdomain.com, your brand
Calendly
calendly.com/you

Calendly ↗

VS	Cal.diy	Calendly ↗
Price	€0, forever	€12/mo per user
Event types	Unlimited (15 min, 30 min, 1 h…)	One on the free plan
Your link	book.yourdomain.com, your brand	calendly.com/you
Your calendar data	At home (self-hosted)	On their servers
Integrations	Google Calendar, Meet, webhooks included	Locked behind paid plans

How to install it (even from zero)

This is the heaviest deployment in the library: a real app with its own database, hosted on a server. Exactly the kind of job I hand to Claude, and that is how mine was set up.

1
Plan the hosting and the subdomain
You need somewhere for the app to run day and night: a VPS with Docker, or a platform like Railway. Plus a subdomain of your own, like book.yourdomain.com.

Paste this prompt into Claude

It will deploy the app, create the database, write the configuration and check that your page responds:

Déploie cal.diy (l'outil open source de prise de rendez-vous, repo calcom/cal.diy, image Docker officielle calcom/cal.diy) sur mon hébergement, avec une base PostgreSQL. Configure les variables d'environnement nécessaires (NEXTAUTH_SECRET, CALENDSO_ENCRYPTION_KEY, l'URL publique), branche l'envoi d'emails, puis vérifie que la page de réservation répond sur mon sous-domaine. Attention : si mon hébergeur bloque le SMTP sortant, passe par l'API HTTP d'un service d'emails comme Resend. Explique-moi chaque étape simplement, je débute.

Review the GitHub repository and check whether it is safe to install given my machine and my infrastructure. Ask me as many questions as possible, using widgets, to clarify my request and be as precise as you can.

3
Connect Google Calendar and set your availability
Connect your calendar in the settings, define your open hours, create your event types. Hard-earned tip: any event marked Busy in Google blocks your slots. Switch your routine blocks to Free, or your page will always look full.

What you actually do with it

Sell your calls without back-and-forth

Consultation, audit, discovery call: you send one link, the client picks a slot, the Meet link is created and the confirmation email goes out on its own. Zero messages asking if Tuesday at 3 works.

One link per meeting type

15 minutes for a first contact, 30 for a follow-up, an hour for a consultation: each link has its own duration, its own booking questions and its own rules.

Your calendar drives your slots

Your real meetings automatically block slots. Your routines stay visible in your calendar without blocking anything. Nobody can book during your workout.

Project health, at a glance

Before installing an open-source tool, one question matters: is the project alive? These scores are computed from public GitHub data. They are not made up.

72/100

Good

Healthy, followed project: a good everyday choice.

Activity: 60
Maintenance: 100
Community: 95
Maturity: 100
Momentum: 3

The repo in numbers

GitHub stars: 48.5k
Forks: 15.2k
Contributors: 436
Commits: 16.5k
Project age: 5.5 yrs
Last commit: 3 d ago
Size: 1129.6 MB
License: MIT

Built with

TypeScript 95.7%
CSS 2.1%
HTML 0.7%
PLpgSQL 0.6%

Scores computed automatically from the GitHub API (last-30-days activity, update freshness, community size, project age). Refreshed daily.

Loucash’s take

9/10

This is the infrastructure my business runs on daily: every call with my students and clients goes through it, in production. I will not lie to you, it is the heaviest deployment in this library and genuinely an advanced level: you need a server, a database and some time ahead of you. But that is exactly where it pays off. You open one account per person on your team, each with their own link, calendar and availability, and you never pay per seat. Calendly at €12 per person per month, across five people over two years, is €1,440. Here, you pay for your server, full stop. The bigger your team grows, the wider the gap works in your favour. Two hard-earned traps to know. On Railway, outbound SMTP is blocked: I wired the emails through Resend's HTTP API, plan for it from day one. And on the Google Calendar side, any event marked Busy blocks your slots: switch your routine blocks to Free, or you will end up with two slots a day. One heads-up so you are not caught out: Cal.com's advanced team features (round robin distributed bookings, collective events) have been removed from this edition. Everyone gets their own account and link, which already covers the vast majority of needs.

It’s for you if: You sell calls or follow-ups (consultations, audits, coaching), solo or with a team, and you want your booking link on your own domain without paying per seat.