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Generating types

To work with Kysely, you're required to provide a database schema type definition to the Kysely constructor.

In many cases, defining your database schema definitions manually is good enough.

However, when building production applications, it's best to stay aligned with the database schema, by automatically generating the database schema type definitions.

There are several ways to do this using third-party libraries:

  • kysely-codegen - This library generates Kysely database schema type definitions by connecting to and introspecting your database. Its CLI supports PostgreSQL, MySQL, SQLite, and Microsoft SQL Server. PGlite is not a CLI dialect; generating types from an in-process PGlite database requires a programmatic integration.

  • kysely-typegen - This library generates Kysely database schema type definitions by introspecting your database through the Kysely instance you pass to it. It is used programmatically rather than as a CLI, so it also works with in-process databases such as PGlite. It supports PostgreSQL, PGlite, MySQL, and SQLite, has no runtime dependencies, and can be extended to more dialects.

  • prisma-kysely - This library generates Kysely database schema type definitions from your existing Prisma schemas.

  • kanel-kysely - This library generates Kysely database schema type definitions by connecting to and introspecting your database. This library extends Kanel which is a mature PostgreSQL-only type generator.

  • kysely-schema-generator - This library generates Kysely database schema type definitions by connecting to and introspecting your database. Current MySQL only.