A developer is building xitdb, a database designed to address what they see as SQLite's core limitations. While SQLite revolutionized embedded databases, its 150,000-line C codebase isn't truly lightweight, and its mutable nature creates impedance mismatches and concurrency limits. The new project aims for a fundamentally different architecture.

Instead of a built-in SQL engine, xitdb provides native in-memory data structures like HashMaps and ArrayLists across Zig, Java, and Clojure. This eliminates the glue code needed to map application objects to database tables. Its immutable design, inspired by Datomic, allows safe concurrent reads and full time-travel queries, letting users revert to any previous database state.

The creator argues the next generation of databases will be SQL-free and immutable, though they acknowledge SQLite's creator, Richard Hipp, built his system through decades of humble, consistent work. xitdb itself is about 3,000 lines with no dependencies, positioning it as a truly lightweight alternative for developers who want to build their own data models on top of a simple core.