Seedling
Relational Test Data Factory
Seedling is a schema-aware test data generator. Point it at a Postgres or MySQL schema and it produces referentially-integer rows that respect every foreign key, unique constraint, and column type.
It auto-detects column types from your schema, maps them to built-in generators, and streams rows in dependency order (topological sort by FK). You can override any column with custom generators via a simple YAML DSL.
Key Features
- Schema introspection — Reads live Postgres and MySQL databases
- Auto-generated data — Column names and types map to realistic generators (email, name, phone, geography, finance, and more)
- Generator overrides — YAML-based DSL to customize per-column generation
- Deterministic output — Same schema + seed + count = byte-identical results
- Multiple output formats — SQL, CSV, JSON Lines, Parquet, direct DB insert, Postgres COPY
- Circular FK handling — Self-referencing tables and circular dependency loops
- Fast streaming — Parallel generation of independent table subgraphs
- Watch mode — Auto-regenerate on schema changes