AlaSQL

AlaSQL (v4.17.3) is an open-source JavaScript SQL database for in-memory data processing, ETL, and browser/Node.js/mobile apps. It supports querying JavaScript arrays, objects, Excel (XLS/XLSX), CSV, JSON, IndexedDB, LocalStorage, and SQLite files with SQL-99 syntax and NoSQL extensions. Over 650k monthly downloads, weekly releases on npm. Key differentiators: direct query on nested JSON, relational joins across heterogeneous data sources, and no server required. Ships TypeScript types and works with ESM, CJS, and browser script tags.