Last Updated: 3/9/2026

Plugin system

Plugins are classes that implement KyselyPlugin . Plugins are then added to the Kysely instance as follows:


const db = new Kysely<Database>({
  dialect: new PostgresDialect({
    database: 'kysely_test',
    host: 'localhost',
  }),
  plugins: [new CamelCasePlugin()],
})

Built-in plugins

Camel case plugin

A plugin that converts snake_case identifiers in the database into camelCase in the JavaScript side. Learn more .

Deduplicate joins plugin

A plugin that removes duplicate joins from queries. You can read more about it in the examples section or check the API docs .

Handle `in ()` and `not in ()` plugin

A plugin that allows handling in () and not in () with a chosen strategy. Learn more .

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