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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
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.
What is Kysely?
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.
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Kysely FAQ
How does Kysely ensure type-safety for database queries?
Kysely achieves type-safety through its state-of-the-art API, which provides precise result types and catches errors within queries at compile-time. It can also use
kysely-codegen to generate types directly from the database schema, making the database the source of truth for types.What SQL operations and clauses does Kysely support?
Kysely supports building a wide range of SQL queries, clauses, functions, and expressions. This includes common operations like SELECT, INSERT, UPDATE, DELETE, and MERGE, as well as more advanced features like WITH clauses.
Which SQL databases are officially supported by Kysely?
Kysely ships with official dialects for PostgreSQL, MySQL, MS SQL Server, and SQLite. Its community-driven dialect system also allows for easy implementation of support for other SQL databases.
Can Kysely be used in environments other than Node.js?
Yes, Kysely is designed to run in any JavaScript environment. It is lightweight, has zero dependencies, and avoids environment-specific APIs, making it compatible with Node.js, Deno, Bun, AWS Lambda, Cloudflare Workers, and even browsers.
How does Kysely handle database migrations?
Kysely provides optional up/down migration primitives, allowing users to write their own migrations. The
kysely-ctl tool can then be used to run these migrations directly from the terminal or within a CI/CD pipeline.What is the purpose of Kysely's plugin system?
The plugin system allows users to tap into the query process to modify queries before compilation or their results after execution. This enables various use cases, such as automatically transforming camelCase names to snake_case and vice versa.
Source: kysely.dev