Hey there 👋🐱 it's Peer, cofounder of Cal.com. today we are launching Cal.com 4.0 which is our largest release ever. Cal.com is going from a single product to a multi-product with the launch of Cal.com Platform, a headless scheduling API powered by Cal Atoms, a set of plug & play react components. ⚛️ story time 👇 when my YC company shutdown during covid i needed a job. And because i suck at interviews i did what i can do best: i started building. i saw a lot of other founders shutting down their business too, so i built a marketplace to hire ex-yc founders as contractors. you might be surprised, but we used calendly to facilitate the meeting and asked for their link during the onboarding. and to be frank, it sucked. its simply not what its built for. i couldnt manage users, people didnt had an account or typos in their links, they forgot to upgrade and most importantly: i could not customise the experience. it was fully branded, felt foreign and would not work at scale with so many issues. i needed something i could be in charge of. so i googled "calendly open source" and found 0 results. just a couple hackernews and reddit posts asking for the same damn thing. ~~two days later~~ (*imagine the french spongebob narrator voice*) i started hacking on a landing page and together with @baileypumfleet, calendso was born. we launched and, well, the rest you've probably seen here on product hunt. anyway, we took a bit of a detour from building the "developer focussed headless scheduling infrastructure" and started out building a consumer facing scheduling tool instead after buying the cal.com domain. why? well – we wanted to build something that would delight people first. the most pixel-perfect, fast, secure (SOC2, ISO27001, HIPAA), safe and accessible (open source) product for everyone. if you look into the market of developer tools, a lot of these "scheduling apis" have never been touched by a consumer. it's a group of developers thinking about "hmmm what do i think other developers need" and not "what is the best for the actual host and guest" you get scheduling apis that are outdated or just "a part of a broader offering of APIs" like Nylas, that dont get the love that they deserve. scheduling is hard. timezones suck, calendar apis are older than your grand dad (seriously) but after facilitating multiple millions of bookings with our consumer facing product we are now going back to our roots: Scheduling Infrastructure for absolutely everyone. we are dog-fooding our own apis, using our own components, so you can be sure what you are using for your next big idea has been battle tested by millions of people and designed by a team that really really cares about calendar scheduling. sometimes all you have to do is go full circle and start at the beginning. today we are launching cal.com 4.0 but we are just getting started! Peer p.s. huge shoutout to everyone who has been supporting us. it is truly inspiring to be working with such an awesome community and go from a small side project on github to an organization that eventually connects 1 billion people. 🙏

I know healthtech startups who built for the first months nothing else than the scheduling part of their product. It wasn't the core or the unique part of their business. But they just underestimated the effort and were like "well it's timeslots how hard can it be". They ended up with a brittle setup and lost months of product development. Excited that Cal now offers headless infra!

Very excited for this launch! I've already seen a ton of Cal.com embeds – this will only take those embeds to the next level with custom styling. Congrats team!

This is the answer to what if shadcn would have actually joined cal.com

I've been using cal.com for a few years now, came from calendly one was like using a horse and cart - the other a futuristic flying car as a product maker, I am super excited to start nesting Cal's atoms into our services the possibilities are endless, and our users will love it p.s. I can no longer book calendly links, theres a mental block. spoke to my therapist, they tried cal, and now they suffer the same. apparently its called SuperiorCalism

Cal is always one of my favorites for call scheduling with potential clients. Thanks for creating this gem!

Love this launch! Great work @peer_rich and Team Cal

COSS for the win! 🥇

Everytime I see cal.com, I'm like: Why does calendly even exist xD

This is big. Atoms is one of those 'obvious' products that has been so desperately needed. Knowing that there's finally a calendar library that will get treated as a first-class citizen is refreshing. Fantastic documentation, as well. Kudos to whoever worked on that.

This is a good product. Good Luck, @peer_rich !

cal 4.0! <3 Love this to bits! Excited to try atoms!

You are all doing a great job at Cal.com! I'm a big fan of your product, and I hope you take the 1st spot today! 🏆 Congrats on the launch and good luck! 🤞

Super cool approach to make building on top of the open source scheduling infrastructure very easy! Will checkout in detail, Atoms is also a great name for a component library 😍

Love it! Clean docs and awesome old windows theme. Congrats to the team 🔥

Oh, also try our replit example: https://go.cal.com/replit

It's inspiring to see how your journey from a YC shutdown led to the creation of such a powerful scheduling platform. I'm curious, what are some of the key features or improvements that users can expect from Cal.com platform compared to traditional scheduling APIs like Nylas?

We use Cal.com to talk to every new prospect, and setup calls with all of our existing customers. Life would not be the same without Cal.com. So excited for the v4 release!!! 🚀

Congrats on the release team. Can't wait to use it to build some automagical scheduling infra for my own product. Let's go 🔥

So excited for this launch! Great work by the team shipping so many cool things! Avid user of the product and fan of the team! lets gooooooo! 🫶🫡