Cal.com: Open Source Scheduling for Everyone

If you've ever tried to integrate scheduling into an app, you know the pain. It's more than just displaying availability—it's time zones, calendar sync, meeting buffers, and a dozen other details. Most solutions are either too rigid, too expensive, or both. That's where Cal.com comes in.

Cal.com is an open source scheduling infrastructure that aims to be the one-stop shop for booking meetings, appointments, and events. It’s built for developers who need a flexible, self-hostable alternative to tools like Calendly or Acuity.

What It Does

At its core, Cal.com handles the entire scheduling workflow. Users can set their availability, create booking page links, and manage events across multiple calendars. It supports team scheduling, round-robin event types, and a wide range of integrations (Google Calendar, Outlook, Zoom, and more).

But what sets it apart is its developer-first approach. You can host it yourself, extend it with custom integrations, or even embed it as a component in your own application. It’s not just a SaaS product—it’s a toolkit.

Why It’s Cool

For starters, it’s fully open source (MIT licensed). That means you can see how it works, modify it, and contribute back. The codebase is modern TypeScript, using Next.js and Prisma, making it approachable for web developers.

It also has a built-in widget system and API that lets you embed booking functionality directly into your site or app. Want to offer one-click scheduling from your product? Cal.com makes it straightforward.

The project is also highly active, with a large community and frequent updates. With over 37k stars on GitHub, it’s clear that developers are excited about what they’re building.

How to Try It

The easiest way to get started is with the hosted version at cal.com. You can sign up and start creating booking pages in minutes.

If you want to self-host, you can deploy it with Docker, Kubernetes, or even use a one-click deploy on platforms like Railway or Vercel. The GitHub repo has detailed docs to help you get going.

There’s also a playground for testing the embed features and a growing library of APIs for deeper integration.

Final Thoughts

Cal.com is one of those projects that just makes sense. It solves a real problem in a way that’s both powerful and accessible. Whether you’re building a SaaS app, a community platform, or just want more control over your scheduling tools, it’s worth a look.

It’s not every day you find open source software that’s this polished and well-supported. If you’re a developer looking to add scheduling, this might be all you need.

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