Apache 2.0, no small print.

Apache 2.0 is a permissive licence: you may use, modify and distribute the software, including inside proprietary products, as long as you keep the copyright notice and the licence itself. It also includes an express patent grant, which is exactly what shorter licences tend to leave out.

We say so because it matters in regulated procurement: many open source policies in banking and government rule out network copyleft licences such as AGPL. Apache 2.0 clears those filters without negotiation.