xitdb Immutable Database

xitdb (current version 0.13.0) is an embedded, immutable database library for TypeScript and JavaScript, designed for storing and managing structured data in a versioned manner. It excels by efficiently creating a new "copy" of the database with each transaction, allowing past states to be read from or reverted to. Unlike traditional databases, xitdb operates without a query engine, instead providing direct APIs to manipulate core data structures like ArrayList and HashMap, which can be nested arbitrarily. It supports both single-file and in-memory storage, incrementally reading and writing to handle datasets larger than available memory. A key differentiator is its entirely synchronous API, eliminating the need for `async/await`, and its pure TypeScript implementation with no external dependencies beyond the JavaScript standard library. Reads never block writes, and multiple threads/processes can access the database concurrently without locks. This makes it a powerful alternative to SQL databases like SQLite for applications requiring simplicity, immutability, and tight integration with native TypeScript data structures, especially in scenarios akin to version control systems. The project is under active development, with an irregular, feature-driven release cadence, reflecting its 0.x version status.