Drizzle ORM is a headless, type-safe SQL query builder and ORM for TypeScript/JavaScript, supporting PostgreSQL, MySQL, SQLite, and serverless databases (Neon, PlanetScale, Cloudflare D1, Turso, etc.). The repository is a monorepo containing the core ORM library (`drizzle-orm`), a CLI tool (`drizzle-kit`) for schema introspection, migration generation, and database push/pull, a data seeding library (`drizzle-seed`), validation schema generators (`drizzle-zod`, `drizzle-valibot`, `drizzle-typebox`, `drizzle-arktype`), and an ESLint plugin (`eslint-plugin-drizzle`). The architecture follows a dialect abstraction pattern: each database has its own column builders, query builders (select, insert, update, delete), and session implementations that wrap native client libraries. The core provides composable SQL building via template literals, runtime type identification via the `entityKind` pattern, and a caching layer with tag-based invalidation. The CLI uses Zod-based configuration validation and generates migration SQL by diffing serialized schema snapshots. Integration tests run against real databases in Docker containers, and extensive type tests ensure compile-time correctness. External dependencies include various database client libraries (pg, mysql2, better-sqlite3, libsql, @neondatabase/serverless, etc.) and validation libraries (zod, valibot, typebox, arktype).