SeedKit

Generate realistic, constraint-safe seed data for any database.

SeedKit connects to your PostgreSQL, MySQL, or SQLite database, reads the schema, and generates seed data that respects foreign keys, unique constraints, check constraints, and enum types -- all without copying production data.

Install

npm install -g @seed-kit/cli

Or run without installing:

npx @seed-kit/cli generate --db postgres://localhost/myapp --rows 1000

Quick Start

# Generate 1000 rows per table as SQL
seedkit generate --db postgres://localhost/myapp --rows 1000 --output seed.sql

# Insert directly into database
seedkit generate --db postgres://localhost/myapp --rows 1000

# JSON or CSV output
seedkit generate --db postgres://localhost/myapp --rows 100 --output data.json

# Deterministic output with seed
seedkit generate --db postgres://localhost/myapp --rows 100 --seed 42 --output seed.sql

Database Connection

SeedKit automatically finds your database URL by checking (in order):

1. --db CLI flag
2. DATABASE_URL environment variable
3. .env file in the current directory
4. seedkit.toml config file

Supported URL formats:

# PostgreSQL
seedkit generate --db postgres://user:pass@localhost:5432/mydb

# MySQL
seedkit generate --db mysql://user:pass@localhost:3306/mydb

# SQLite
seedkit generate --db sqlite://path/to/db.sqlite

AI-Enhanced Classification

SeedKit can use an LLM to improve column classification beyond the built-in 50+ regex rules. This helps with ambiguous column names that the rule engine classifies as Unknown.

# Set one of these environment variables:
export ANTHROPIC_API_KEY=sk-ant-...    # Uses Claude Sonnet (default)
export OPENAI_API_KEY=sk-...           # Uses GPT-4o (default)

# Run with --ai flag
seedkit generate --db postgres://localhost/myapp --rows 1000 --ai --output seed.sql

# Override the model
seedkit generate --db postgres://localhost/myapp --rows 1000 --ai --model claude-opus-4-20250514

The AI classification is cached locally so subsequent runs with the same schema don't re-query the LLM. Results are also stored in the lock file for team reproducibility.

Smart Sampling

Extract statistical distributions from a production database to generate data that mirrors real patterns:

# Sample distributions (read-only, PII auto-masked)
seedkit sample --db postgres://readonly-replica:5432/myapp

# Generate using sampled distributions
seedkit generate --db postgres://localhost/myapp --rows 1000 --subset seedkit.distributions.json

All Commands

| Command | Description | |---|---| | seedkit generate | Generate seed data (SQL, JSON, CSV, or direct insert) | | seedkit sample | Extract production distributions with PII masking | | seedkit introspect | Analyze schema and show classification results | | seedkit preview | Preview sample rows without full generation | | seedkit check | Detect schema drift against lock file (CI-friendly) | | seedkit graph | Visualize table dependencies (Mermaid or Graphviz) |

Configuration

Create a seedkit.toml in your project root:

[database]
url = "postgres://localhost/myapp"

[generate]
rows = 500
seed = 42

[tables.users]
rows = 1000

[tables.orders]
rows = 5000

# Custom value lists with optional weights
[columns."products.color"]
values = ["red", "blue", "green", "black", "white"]
weights = [0.25, 0.20, 0.20, 0.20, 0.15]

Supported Platforms

| Platform | Architecture | |---|---| | Linux | x64, ARM64 | | macOS | Intel, Apple Silicon | | Windows | x64 |

Documentation

Full documentation, architecture details, and benchmarks: github.com/kclaka/seedkit

License

MIT