It gives you the ability to market to developers and post on HN without actually making it easy to host the open source version

It also assures customers who have concerns about the longevity of your company that, even if you folded, your product itself wouldn't just vanish. So it's a kind of insurance in addition to being a marketing strategy.

https://cal.com/blog/longevity 100%

As somebody who's planning on going this route too, I love this blog post and will likely write/do something similar when I get there.

Big fan of Cal.com and other open source businesses like it.

Anybody with money to spend is going to be astute enough to realise that the burden of self-hosting is far above any potential direct cost savings, and so self-hosting becomes an option utilised only by those who probably wouldn’t be going to pay for it anyway. Essentially, it’s a pain-in-the-ass free tier.

They have a paid self-host option… starts at $189/month.

(with enterprise features that most people don't need)

Why do you spin it so negatively?

If it’s going to be utilized almost exclusively by those who wouldn’t pay anyway, then as a business there is no loss of revenue by providing an open-source version.

And although this company may not want to or be able to afford to spend much making it easy, I’ve used one piece of software that the business goes to great lengths to make easy to self-host.

My phrasing must be bad because you've just said exactly what I was trying to say. I certainly don't intend to frame it as a bad choice, I think it's a great choice, I was addressing why offering open-source does not cannibalise paid customers and why it can be a sensible business decision: people who would choose to self-host aren't going to pay anyway.

Maybe "pain-in-the-ass free tier" was unclear, I mean from the perspective of a customer: it's such a pain in the ass to get the product for free that it makes sense to pay for it for almost everyone.

Free is a great foot in the door, and self-hosting every single application you need as your business grows gets complicated.

They get the attention and business of people like me who actively avoid vendor lock-in. I'm very open to (and often end up becoming a paid customer) products that have open options, and I also typically bring my org along with me. Most recently I did this with Tailscale. (Note: If not for the Headscale project, I would never have become a Tailscale customer so their openness is gained them at least one ARR of about $2k that they otherwise would not have gotten)

I also tend to self-host my personal stuff but pay for hosted for the business, knowing that if the product changed in unsavory ways (pricing, closed-nature, etc) the business could self-host and escape a hostage situation. It's far from perfect as usually there's a bunch of data in their DB that you can't easily export, but with proprietary/closed solutions that's nearly guaranteed to be the case.

People used to sell software. Now they give away the software, but get first dibs on hosting it for a monthly fee.

Works well for anything that Amazon can't be bothered hosting :-), basically apps not infrastucture (although this title wierdly calls itself infrastructure, but that is probably sales hyperbole).

Another reason I really like open core, besides the reasons mentioned, is that suggesting and collaborating on features that I'd like is a much better experience through GitHub or GitLab than it is via some terrible support channel where I know it's never going to be seen ever again.

Hey - one of the cofounders here.

There’s a lot of reasons why we’re open core.

First is longevity. Especially considering we’re a startup, if a huge company is evaluating using our product, they’re going to wonder if we’re going to disappear in a few years. Open source doesn’t disappear: https://cal.com/blog/longevity

Secondly is that we’re a developer focused product, and so making it open source for hobbyists to play around with is a great way to introduce people to our product with the hopes that one day they’ll build their next company using our scheduling (so it does help as a sales channel, although definitely not the primary reason)

Also transparency and privacy. Users know how their data is being handled, which for me personally is a huge plus. I want to know what the software is doing if I’m giving it access to my calendar.

There are a few other reasons too, maybe I’ll write something on the Cal.com blog