kysely-schema

Schema-first development tool for Kysely — Prisma's DX + Kysely's power + Zero runtime overhead

⚠️ Development Status

This package is in early development and undergoing active testing. Expect breaking changes between minor versions. Not recommended for production use yet.

Features

• 📝 Schema-first — Define your database schema in TypeScript
• 🔄 Auto-migrations — Generate Kysely migration files from schema changes
• 🎯 Type-safe — Auto-generate TypeScript types for your Kysely queries
• 🪶 Lightweight — Zero runtime overhead, pure code generation
• 💪 Full SQL control — Generates standard Kysely schema builder code
• 🔌 Works with Kysely — Complements existing Kysely migrations, doesn't replace them

Quick Start

# Install
npm install -D kysely-schema-cli
# or
pnpm add -D kysely-schema-cli

# Initialize (installs kysely + db driver for you)
npx kysely-schema init
# or
npx kys init 

Define your schema in schema/index.ts:

import { defineSchema, table, column } from 'kysely-schema';

export default defineSchema({
  user: table({
    id: column.serial().primaryKey(),
    email: column.text().notNull().unique(),
    name: column.text().nullable(),
    createdAt: column.timestamp().default('now()').notNull(),
  }),

  post: table({
    id: column.serial().primaryKey(),
    title: column.text().notNull(),
    content: column.text().nullable(),
    authorId: column.integer().notNull().references('user', 'id').onDelete('cascade'),
    createdAt: column.timestamp().default('now()').notNull(),
  }),
});

Generate migrations and types:

# Generate a Kysely migration
npx kysely-schema generate-migration "initial"
# or
npx kys gm "initial"

# Generate TypeScript types
npx kysely-schema generate-types
# or
npx kys gt

# Run migration (standard Kysely)
npx kysely migrate:latest

CLI Commands

| Command | Alias | Description | |---------|-------|-------------| | init | — | Scaffold config, schema, migrations, and generated dirs | | generate-migration <name> | gm | Generate a Kysely migration file from your schema | | generate-types | gt | Generate TypeScript Database interface | | diff | — | Show schema changes since last migration | | validate | — | Validate your schema definition | | dev | — | Watch schema, auto-regenerate types, validate, and show diffs |

Comparison

| Feature | Prisma | kysely-codegen | kysely-schema | |---------|--------|----------------|-------------------| | Schema-first | ✅ | ❌ | ✅ | | Lightweight | ❌ | ✅ | ✅ | | Full SQL control | ❌ | ✅ | ✅ | | Auto-migrations | ✅ | ❌ | ✅ | | Type generation | ✅ | ✅ | ✅ | | Runtime overhead | Heavy | None | None |

Documentation

• Getting Started
• Schema Definition
• Migrations
• API Reference

Contributing

This project is open source and we welcome contributions!

• 🐛 Report bugs: GitHub Issues
• 💡 Feature requests: GitHub Discussions
• 🔀 Pull requests: GitHub Repository

License

MIT