- Its size is less than a megabyte: https://sqlite.org/footprint.html
- 750KB if all features are enabled: https://www.sqlite.org/about.html
- Looks like fair amount of functionality can be left out when compiling sqlite and with options to influence/strip down query planner: https://www.sqlite.org/compile.html
- And "SQLite does not compete with client/server databases. SQLite competes with fopen()": https://www.sqlite.org/whentouse.html
In the end, you don't need a database, but a library that gives you database API and behavior.