OpenSchema

A schema definition language and code generator. Write your data model once and generate SQL tables, TypeScript and Go types, JSON Schema, GraphQL, and OpenAPI — all guaranteed to agree, because they come from the same source.

Built for organizations where many teams or companies share one core schema but each needs private fields of their own, without forking and without collisions.

namespace shop

enum OrderStatus { 1 pending  2 shipped  3 delivered }

@table("orders")
model Order {
  @primaryKey @default(gen_uuid())
  1 id: uuid

  2 status: OrderStatus

  @minValue(0)
  3 total: decimal(12, 2)

  4 note: string?
}

openschema order.schema --target sql --out ./generated

CREATE TABLE orders (
  id UUID NOT NULL PRIMARY KEY DEFAULT gen_uuid(),
  status TEXT NOT NULL,
  total NUMERIC(12, 2) NOT NULL,
  note TEXT
);

Install and run

bun install
bun run src/cli/index.ts --help

# or build a standalone binary:
bun build src/cli/index.ts --compile --outfile openschema

What it does

• One source, many targets. SQL DDL, TypeScript, Go, JSON Schema, GraphQL, and OpenAPI.
• Protobuf-style field numbers give every field a stable identity, so the compatibility checker can tell a safe rename from a breaking removal.
• Per-company overlays let many companies extend a shared schema with private fields in isolated number spaces.
• Compatibility checking (diff / check) gates schema changes in CI.

Documentation

Full documentation is in docs/:

• Getting Started
• Language Reference
• Decorators
• Code Generation
• Overlays
• Compatibility Checking
• CLI Reference
• Use Cases

Worked examples live in examples/, including a multi-file, multi-company project in examples/ecommerce/.

Development

bun test