Dyalog APL is commercial, but they are open-source friendly. I work with and am sponsored by them, and we are actively working to open-source as much as is poss

Dyalog APL is commercial, but they are open-source friendly. I work with and am sponsored by them, and we are actively working to open-source as much as is possible provided that we can continue to support the projects. Similarly, they release software like MiServer, which is a web server in pure APL as open source.