Stemma

Stemma is a collaborative family tree editor. It lets multiple people build and maintain a shared genealogy, with permissions and invitation links.

Features

• Create and edit family trees with parent/child relationships
• Invite collaborators via shareable links
• Visual graph rendering of the tree
• Per-person edit permissions

Tech stack

• Frontend: Svelte + Rollup
• Backend: Scala (ZIO, zhttp)
• Storage: PostgreSQL

Repository layout

• backend/: Scala backend root
• backend/build.sbt, backend/project/: SBT root and build config
• backend/src/api/: domain model and core services
• backend/src/api_impl_restful/: REST API implementation (local server)
• backend/src/api_impl_aws_lambda/: AWS Lambda implementation
• frontend/: Svelte frontend
• e2e/: Playwright end-to-end tests and local dev stack launcher

Quick start (local)

Prerequisites

• Java 11+
• sbt
• Node.js + npm
• PostgreSQL (or Docker)

1) Start Postgres (Docker)

docker run --name stemma-postgres \
  -e POSTGRES_PASSWORD=mysecretpassword \
  -e POSTGRES_DB=stemma \
  --rm -p 5432:5432 postgres

2) Run the backend

export GOOGLE_CLIENT_ID=your_google_client_id
export INVITE_SECRET=your_invite_secret
export JDBC_URL=jdbc:postgresql://localhost:5432/stemma
export JDBC_USER=postgres
export JDBC_PASSWORD=mysecretpassword
cd backend
sbt "project api_impl_restful" run

The REST API listens on http://localhost:8090.

3) Run the frontend

cd frontend
npm install

GOOGLE_CLIENT_ID=your_google_client_id \
STEMMA_BACKEND_URL=http://localhost:8090 \
npm run dev

Open the dev server URL printed by Rollup.

Tests

cd backend
sbt test

cd frontend
npm test

cd e2e
npm test

Environment variables

Backend:

• GOOGLE_CLIENT_ID: Google OAuth client ID
• INVITE_SECRET: secret for invitation token signing
• JDBC_URL: PostgreSQL JDBC URL
• JDBC_USER: database user
• JDBC_PASSWORD: database password
• E2E_AUTH_BYPASS (optional): when set to 1 in api_impl_restful, any bearer token is accepted (for E2E only)

Frontend:

• GOOGLE_CLIENT_ID: same client ID as backend
• STEMMA_BACKEND_URL: backend base URL (for example http://localhost:8090)

Notes

• If you change the schema or need a clean start, drop the database and re-run the backend to recreate the schema.