Open Weights

The distinction matters more than the industry's vocabulary suggests. Open weights means the trained parameters are downloadable, so you can run the model on your own hardware. Open source, properly used, additionally means a license granting broad rights to use, modify and redistribute — typically with the training code and data pipeline available too.

Most models described in the press as "open source" are open-weight releases under custom licenses. Those licenses routinely carry restrictions a genuinely open license would not: revenue or user thresholds above which terms change, mandatory attribution, bans on training competing models, and in some cases geographic exclusions barring use in particular countries entirely.

A downloadable model, a public repository and a permissive-sounding announcement are all compatible with a license that forbids the thing you want to do.

Teams adopt open-weight models specifically to gain control — over cost, over data residency, over their own roadmap. A license restriction discovered after deployment defeats that entirely, and these terms are load-bearing for exactly the commercial use cases that motivate self-hosting in the first place.

Read the actual license file, not the announcement or the coverage. Four questions settle most cases: is commercial use permitted at all; are there revenue or user thresholds; is attribution or a no-compete clause mandatory; and is your country excluded? Note that restrictions often apply to the downloadable weights while the hosted API stays generally available, so say which path is actually open to you.