"I assumed the license was OK considering its popularity."

Always check the licence. Public domain, MIT, simple, plain BSD, GPL (any version), apache - if it's anything else, be extremely cautious.

> Public domain

There are jurisdictions that don't recognize PD grants. I can't think of a good reason to use CC0 over MIT or BSD.

> GPL (any version)

This might be doctrinaire but I won't use the (L)GPLv3 because of the AGPL linking clause:

> Notwithstanding any other provision of this License, you have permission to link or combine any covered work with a work licensed under version 3 of the GNU Affero General Public License into a single combined work, and to convey the resulting work. The terms of this License will continue to apply to the part which is the covered work, but the special requirements of the GNU Affero General Public License, section 13, concerning interaction through a network will apply to the combination as such.

CC0, Unlicense etc. always contain fallbacks for jurisdictions without PD grants. That's the whole point of using them instead of just saying "public domain" and nothing more.

There's also the Zero-clause BSD License https://spdx.org/licenses/0BSD.html which is the same kind of thing except it does not even mention the words "public domain".

If it's anything else, I would say start by checking the Open Source Initiative Web site: https://opensource.org/licenses

Still, be cautious. The OSI has approved a number of bad licenses. The UPL (https://opensource.org/licenses/UPL) stands out to me as one that should've been rejected.

Why?

The discussion around its approval was contentious. My reading is that it exists primarily as an Oracle CLA. The license wasn't rigorously reviewed by non-Oracle counsel and there's some worry about hidden landmines.

https://lists.opensource.org/pipermail/license-review/2014-A...

https://lists.opensource.org/pipermail/license-review/2014-S...

As AGPL still on most proples danger list? Or did you not include it in your GPL any version list.

I can't speak for corporate lawyers, but I treat AGPL v3 similar to GPL v3 (a bit truer to the GPL spirit, but in consequence a bit stricter).

Then again, GPL v3 is on many people's danger list

Hey now, the Artistic License is also one you can trust not to bite you in the ass.

What about MPL?

"I assumed the license was OK considering its popularity."

I would have too. I'm getting into Clojure(Script) where React(Native) seems to be a popular choice for UI. I haven't touched it yet. I hope there's a good alternative when I get around to it because I really like Clojure but I never wanted to rely on anything made by Facebook.

There is Reacl. https://github.com/active-group/reacl

Doesn't that still require React under the hood? It's the licensing that's a concern to me, not the code/interface itself.

I'm in the same boat. Hadn't bothered to check out their license yet. Kinda makes me wary about using it for any social platform.

As far as I can tell the license is okay unless your product depends on suing Facebook while at the same time being so strongly dependent on React you can't switch it out.