knex vs Kysely
Which should you use? A side-by-side look at what each one does, who it suits, what it costs, how hard it is to set up, and where each falls short.
Open source · MIT
A JavaScript library for building SQL queries across several databases with one API.
Open source · MIT
A type-safe TypeScript SQL query builder that checks your queries against your table types.
The short answer
Choose knex if you need…
- Node.js developers who need to talk to a SQL database from application code
- Teams that may switch between database engines and want portable query code
- Projects that want a query builder rather than a full ORM
- Developers who want both promise and callback APIs
Choose Kysely if you need…
- TypeScript developers who want SQL control without losing compile-time type checks
- Teams building Node.js backends that query PostgreSQL, MySQL, SQLite or MSSQL
- Developers who want editor autocompletion for table and column names
- Projects that need an escape hatch to raw SQL for cases the types cannot express
Side-by-side
| knex | Kysely | |
|---|---|---|
| Type | Library | Library |
| Price | Free and open source | Free and open source |
| Licence | MIT | MIT |
| GitHub stars | 20.3k | 14.3k |
| Setup difficulty | Intermediate | Intermediate |
| How you get it | Install with a package manager | Install with a package manager |
| Main language | JavaScript | TypeScript |
| Last code update | 4 months ago | 4 days ago |
What each one is
knex
Knex is a query builder for Node.js. You write database queries as JavaScript code instead of raw SQL strings, and the same code works across PostgreSQL, MySQL, MariaDB, CockroachDB, SQL Server, SQLite3 and Oracle. It also provides transactions, connection pooling and streaming queries.
Kysely
Kysely is a library for writing SQL queries in TypeScript. You chain method calls instead of writing raw SQL strings, and TypeScript checks that the tables and columns you use exist and returns result types that match what you selected. It is inspired by Knex.js and is mainly aimed at Node.js, though the README says it also runs in Deno, Bun, Cloudflare Workers and browsers.
Best for
knex
- Node.js developers who need to talk to a SQL database from application code
- Teams that may switch between database engines and want portable query code
- Projects that want a query builder rather than a full ORM
- Developers who want both promise and callback APIs
Kysely
- TypeScript developers who want SQL control without losing compile-time type checks
- Teams building Node.js backends that query PostgreSQL, MySQL, SQLite or MSSQL
- Developers who want editor autocompletion for table and column names
- Projects that need an escape hatch to raw SQL for cases the types cannot express
Strengths
knex
- Supports many SQL dialects behind one query-building interface
- Includes transactions, connection pooling and streaming in the core library
- Has TypeScript typings and a documented ecosystem of plugins and tools
Kysely
- Type inference carries selected columns and aliases through queries, per the README
- API documentation is in the typing files and visible on hover in the IDE
- Supports several SQL dialects, including PostgreSQL, MySQL, SQLite and MSSQL
Not ideal for
knex
- People who are not writing Node.js code, since the library is for JavaScript applications
- Projects that want an ORM with models and relationships; the README points to separate ORMs such as Objection.js, MikroORM and Bookshelf for that
- Beginners with no SQL knowledge, because the query builder still assumes you understand how SQL works
Kysely
- Developers not using TypeScript, since the main benefit depends on the type system
- People who want a full ORM with models, migrations and relationships handled for them, as Kysely is a query builder
- Beginners learning SQL for the first time, who may do better writing plain SQL first
Trade-offs
knex
- Requires Node.js 16 or newer and, for some SQLite drivers, Python and a C++ build toolchain
- Bringing your own knowledge of SQL is still needed; the abstraction does not remove database-specific differences entirely
- README does not detail performance characteristics or the exact behaviour differences between dialects
Kysely
- Its value depends heavily on TypeScript, so JavaScript-only projects gain little
- The README notes some things cannot be typed at compile time and need escape hatches
- As a query builder, it does not provide ORM features such as models or relationship management
Getting started
Frequently asked questions
What is the difference between knex and Kysely?
knex: A JavaScript library for building SQL queries across several databases with one API. Kysely: A type-safe TypeScript SQL query builder that checks your queries against your table types. knex suits node.js developers who need to talk to a sql database from application code, while Kysely suits typescript developers who want sql control without losing compile-time type checks.
Are knex and Kysely free?
knex: Free and open source. Kysely: Free and open source.
Is knex or Kysely more popular?
knex has more GitHub stars (20.3k) than Kysely (14.3k). Popularity isn't the same as fit — check which one matches your use case above.
What are other alternatives to knex and Kysely?
Other options people compare them with include Sequelize, TypeORM, Turso, DuckDB, libSQL.
Keep comparing
Built from our catalogue entries for both products: open-source details come from each project's README (AI-assisted, refreshed weekly) and GitHub data; AI-tool details are editorial. Spotted something wrong? Let us know from either product's page.