alt Hacker NewsI recommend you familiarize yourself with the GPL-3, if you build something based on a GPL-3 piece of software, it's not an 'optional' obligation. If you want to build something on an open source something and keep your derivative private, then use something that originated as BSD licensed, as Sony did with the FreeBSD kernel that ended up in the PS4 and PS5.
GPL v3.0 has a SaaS loophole. The GPL's trigger is conveyance (transferring a copy), not network access. Merely running modified GPL v3.0 code on a server and serving users over HTTP is not "conveying" under the letter of GPL v3.0, so it does not by itself obligate you to release source. This loophole was fixed in AGPL v3.