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Type-safe SQL query builder for JavaScript and TypeScript.

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Tracked since2026
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The Bottom Line

Entry price

Free, no paid tier

Biggest pro

Exceptional type-safety for SQL queries

Biggest con

Requires familiarity with SQL concepts

TL;DR - Kysely

  • Provides a type-safe SQL query builder for JavaScript/TypeScript.
  • Offers precise result types and compile-time error checking for SQL queries.
  • Supports various SQL databases and runs in any JavaScript environment.
Pricing: Free forever
Best for: Individuals & startups

What is Kysely?

Editorial review
Kysely is a state-of-the-art, type-safe SQL query builder designed for JavaScript and TypeScript environments. It provides a thin abstraction layer over SQL, allowing developers to write queries with precise result types and catch errors at compile-time. This focus on type-safety and predictability helps high-performing teams ship software with greater confidence and velocity. Built by SQL enthusiasts, Kysely emphasizes familiarity through its naming and structure, making it easy for SQL-proficient teams to become productive quickly. It supports a wide range of SQL queries, clauses, functions, and expressions, and offers intelligent, context-aware auto-completion based on the database schema. Kysely is highly extensible with a community-driven dialect system, supporting various SQL databases like PostgreSQL, MySQL, MS SQL Server, and SQLite out of the box. It's lightweight, has zero dependencies, and runs in any JavaScript environment, including Node.js, Deno, Bun, AWS Lambda, and browsers. Beyond query building, Kysely includes optional migration primitives for fine-grained control over database schema changes, and a plugin system to modify queries or results. It aims to provide a robust and flexible solution for developers who value type-safety and direct control over their SQL.

Available on: Web

Pros & Cons

Pros

  • Exceptional type-safety for SQL queries
  • Excellent auto-completion experience
  • Thin abstraction layer, close to raw SQL
  • Highly extensible with dialects and plugins
  • Zero dependencies and runs in diverse environments

Cons

  • Requires familiarity with SQL concepts
  • May have a learning curve for those new to SQL query builders

Key Features

Type-safe API with precise result typesCompile-time error detection for SQL queriesAuto-completion for table names, column names, and functionsSupport for a wide range of SQL queries (SELECT, INSERT, UPDATE, DELETE, MERGE, WITH)Ability to use raw SQL strings within structured queriesCommunity-driven dialect system for various SQL databases (PostgreSQL, MySQL, MS SQL Server, SQLite)Zero dependencies and lightweight footprintRuns in Node.js, Deno, Bun, AWS Lambda, Cloudflare Workers, and browsers

Pricing

Free

Kysely is completely free to use with no hidden costs.

View pricing

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Kysely FAQ

How does Kysely ensure type-safety for SQL queries?

Kysely provides a thin abstraction layer over SQL, allowing developers to define queries with precise result types. This design enables the system to catch potential errors at compile-time, enhancing predictability and confidence in the code.

Which teams benefit most from using Kysely?

Kysely is ideal for high-performing teams that value type-safety and direct control over their SQL. Its emphasis on familiarity through naming and structure also makes it particularly suitable for SQL-proficient teams looking to quickly become productive.

How does Kysely compare to Prisma for database interactions?

Kysely offers a thin abstraction layer close to raw SQL, emphasizing type-safe query building and compile-time error catching. In contrast, Prisma is an ORM that typically provides a higher level of abstraction, often generating SQL behind the scenes.

When might Kysely present a learning curve for new users?

Kysely may have a learning curve for developers who are new to SQL query builders or lack familiarity with core SQL concepts. Its design assumes a certain level of SQL proficiency to maximize its benefits.

Does Kysely include a free tier?

Kysely is free to use, meaning there is no paid plan required to access its features and functionalities. It is an open-source tool available for all developers.

Can Kysely be used in different JavaScript environments?

Yes, Kysely is designed to run in any JavaScript environment, including Node.js, Deno, Bun, AWS Lambda, and browsers. It is lightweight and has zero dependencies, contributing to its broad compatibility.

How does Kysely support various SQL databases?

Kysely supports a wide range of SQL databases, such as PostgreSQL, MySQL, MS SQL Server, and SQLite, out of the box. This is achieved through a community-driven dialect system, making it highly extensible.

Source: kysely.dev

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