Kysely (pronounce “Key-Seh-Lee”) is a type-safe and autocompletion-friendly TypeScript SQL query builder. Inspired by Knex.js. Mainly developed for Node.js but also runs on all other JavaScript environments like Deno, Bun, Cloudflare Workers and web browsers.

Kysely makes sure you only refer to tables and columns that are visible to the part of the query you're writing. The result type only has the selected columns with correct types and aliases. As an added bonus you get autocompletion for all that stuff.

As shown in the gif above, through the pure magic of modern TypeScript, Kysely is even able to parse the alias given to pet.name and add the pet_name column to the result row type. Kysely is able to infer column names, aliases and types from selected subqueries, joined subqueries, with statements and pretty much anything you can think of.

Of course there are cases where things cannot be typed at compile time, and Kysely offers escape hatches for these situations. See the sql template tag and the DynamicModule for more info.

All API documentation is written in the typing files and you can simply hover over the module, class or method you're using to see it in your IDE. The same documentation is also hosted here.

If you start using Kysely and can't find something you'd want to use, please open an issue or join our Discord server.

Please visit our documentation site kysely.dev to get started. We also have a comprehensive API documentation hosted here but you can access the same documentation in your IDE by hovering over a class/method/property/whatever.

Want to contribute? Check out our contribution guidelines.