A developer that I follow, just released PocketBase (https://pocketbase.io/) - open source backend with authentication, realtime data and admin dashboard in a single file.
I'm a designer and I use one of his other open source tool - Presentator (https://presentator.io). Based on this github post - https://github.com/presentator/presentator/issues/183, he actually seems to have created PocketBase as a backend for the next Presentator v3.
For an open source project it looks really cool and I think some of you indiehackers may find it interesting.