Glad to see SQLite on then front page -- it's one of the silent workhorses of the modern programming/database world. It
is the most widely deployed database[0]. If you haven't given it a look/aren't interested in it since it seems to be a "toy" database (often the "test" or "local" db for frameworks like rails or django), you owe it to yourself to see what it can really do. Easy to use full text search[1][2], CTEs[3], JSON support via extension[4] (also the extension system is worth looking at[5]) and much much more. There are certainly things that SQLite does
not do, and that's well documented too[6].
If all this doesn't convince you to use SQLite, it's also one of the most well documented large C codebases that is fantastic to learn from.
I'd go as far as to say that many modern startups could get pretty far with SQLite + aggressive caching before even bringing in a big database like Postgres (though with recent deployment/ops advancements it's easier than ever to run postgres).
[0]: https://sqlite.org/mostdeployed.html
[1]: https://www.sqlite.org/fts5.html
[2]: https://sqlite.org/fts3.html
[3]: https://sqlite.org/lang_with.html
[4]: https://www.sqlite.org/json1.html
[5]: https://www.sqlite.org/loadext.html
[6]: https://www.sqlite.org/whentouse.html
If all this doesn't convince you to use SQLite, it's also one of the most well documented large C codebases that is fantastic to learn from.
I'd go as far as to say that many modern startups could get pretty far with SQLite + aggressive caching before even bringing in a big database like Postgres (though with recent deployment/ops advancements it's easier than ever to run postgres).
[0]: https://sqlite.org/mostdeployed.html
[1]: https://www.sqlite.org/fts5.html
[2]: https://sqlite.org/fts3.html
[3]: https://sqlite.org/lang_with.html
[4]: https://www.sqlite.org/json1.html
[5]: https://www.sqlite.org/loadext.html
[6]: https://www.sqlite.org/whentouse.html