Most source-available licenses that I've encountered have no paid license requirements for users. They only require a paid license if you want to sell the product commercially. Normally, you're still allowed to use the software as a piece of a larger commercial product, as long as it does not compete with the original author, or "substantially reproduce the functionality" of the source-available bits, depending on the exact language.

While it's true that this the kind of "source available" license the article is talking about, other examples exist.

For instance, the source code to Epic's Unreal Engine[1] is hosted in a private GitHub repo, accessible by anyone who agrees to a clickthrough license, and free for personal, educational, and commercial use up to $1 million gross revenue, at which point royalty payments are required.

[1] https://www.unrealengine.com/

> Personally I think differentiation between "open source" and "source available" is good

Maybe, but I think that "source available" isn't detailed enough and can mean many many different things.

> Source available means I can basically help debug issues I have...but I expect that a paid licence is required and will have a selection of limitations (number of nodes, etc).

Point in case. For me there is one group, under something like BSL or FSL or SSPL which mostly restricts you from competing with the project's creators (e.g. making your own SaaS out of it), but everything else is fair use, you can use it in prod to make money at any size, etc. And a separate, more restrictive one, which has size, or production restrictions (you can't run the software if you're a commercial entity).

Source available sounds like a good description for the second one, because it's just available, little more. But for the first one where you can do whatever you want with one single exception that doesn't impact 99.9999% of potential users, it's not a good and clear enough description.

People run with OSI initiative as it is and consider it the golden rule when I agree with your 99.9999% of potential users line.

I think that *one blunder?) is that OSI cant really consider SSPL or similar open source because it restricts access to one party so it breaches an freedom 0 or some freedom of open source which is fair but at the same time literally only impacting people competing against (in my opinion the funding of the project and its growth itself) if someone like amazon had created a redis service competing against redis itself lets say

I think its all kinda nuanced and we kinda need more discussion with source available.

I agree with you the "source available" is overstretched. It's hard to come up with a good new label for the first group. Maybe "Open Use" or "Fair Source".

"Source Available" means that it can become "Source Unavailable" overnight.

See the "Our Machinery" fiasco.

Yes, Open Source isn't a complete defense against this (especially when there are copyright assignments). However, it sure makes it both a lot harder to pull off and a lot less useful to even try.

"Open Source" can also become "Source Available" overnight. See Redis, Terraform, etc. In the same vein, "Open Source" can also become "Closed Source" overnight.

In neither case does the change apply retroactively. It only applies to new contributions after the license change.

Well technically Redis had a fork before it became source available known as valkey which is still in bsd license

Terraform was forked to create opentofu if I remember correctly

I think the most recent example is kind of minio for this type of thing no?

Also I am interested what are some open source projects which became closed source since it seems that you haven't named any and I am curious how they can do that. There must be some legal laws protecting it.

If a project switches from an open-source to a closed-source license, then from the outside, it just looks like the project was abandoned. The final commit that was published under the open-source license will always be open source. It's the future commits that are now closed source.

So no, I don't have any specific examples of that happening.

In the case of both Redis and Terraform, the forks were announced after the license change, not before. Indeed, the forks were motivated by the license change. The community didn't get a warning "hey, we're about to change the license, fork it while you still can!". It just changed.

That's what I mean when I say the license change does not apply retroactively. The commit of Terraform that existed before the license change is still open-source. I could create a fork branching off that commit today if I wanted to.

> Also I am interested what are some open source projects which became closed source...

The most prominent one is Solaris. It was open one day, and closed the next. Memo didn't say we're close-sourcing it, but moving to a cathedral (final release as open source only) model, but they never released the sources ever after.

Oracle lost all of the core developers over it.

This where Illumos took over.

> There must be some legal laws protecting it.

For permissively licensed code? Nope. Nothing. Even if you don't transfer the copyright, nothing stops someone from forking it and building on it closed source. That someone would be the company opening it or someone else.

In the olden days, when the internet was not that capable to allow collaborative software development, losing developers was a real threat. Now it's not. Developers are dime a dozen. You can close the source, hire some people and continue working on it.

However, this is Open Source model working as intended. Freedom to the developers! If a developer wants to work on a closed source fork, it's completely permitted, baked into the system.

This is why GPL (esp. v3), while viral, is superior. You can't change the license if there's a copyright holder other than you. You can't just fork and close the source. It's limiting to keep the freedom. A working (and arguably necessary) compromise.

that's not what source available means to me -- it just means you can look at the source code -- what you can actually do with that code, or whether or not you need a paid license, whether you can use the code in a non-commercial case only but not commercial, all of those are nuances that would be specified in the license. There are many different options from highly restrictive to highly permissive -- the only thing they have in common is that you can see the source code.

"open source" can have restrictions too. GPL is highly restrictive because it requires any code linked with the GPL code to be GPL too.

> Open source, is, essentially software that I expect to be able to use commercially and tweak if required - but I'm own my own, and I pay for support.

AND it also means with copyleft-licenses that you are required to make the source code for those tweaks public too.