Yes currently. Hopefully in the future we will open source the app.
Wait, is fountain closed source?
nostr:npub1unmftuzmkpdjxyj4en8r63cm34uuvjn9hnxqz3nz6fls7l5jzzfqtvd0j2
Discussion
Good that you're planning to make it FOSS!
I can only recommend doing it, there are so many benefits, and no substantial reasons against it. Wasabi (and zksnacks) would never have succeeded without it.