Environment Variables

All configuration is managed through environment variables. Copy .env.example to .env for local development.

Required Variables

Variable	Description	Example
ALCHEMY_API_KEY	Alchemy API key for Sepolia RPC and Enhanced APIs	esuQ5PPGg8-Sr5-X-P-JT
DATABASE_URL	PostgreSQL connection string (Prisma format)	postgresql://user:pass@host:5432/oeconomia_explorer

Optional Variables

Variable	Default	Description
ALCHEMY_NETWORK	ETH_SEPOLIA	Alchemy network identifier
PORT	3001	Express server port
REDIS_URL	-	Redis URL for optional caching layer
CLIENT_URL	http://localhost:5173	Frontend URL (CORS origin)
INDEXER_START_BLOCK	auto	Override indexer start block number

Frontend Variables (Vite)

Variables prefixed with VITE_ are embedded into the frontend build:

Variable	Default	Description
VITE_API_URL	http://localhost:3001/api	Backend API base URL
VITE_WS_URL	http://localhost:3001	WebSocket connection URL

VITE_ variables are baked into the frontend at build time. Changing them requires a rebuild.

Example .env File

# ── Alchemy ──
ALCHEMY_API_KEY=your_alchemy_api_key_here
ALCHEMY_NETWORK=ETH_SEPOLIA

# ── Database ──
DATABASE_URL=postgresql://user:password@localhost:5432/oeconomia_explorer

# ── Redis (optional) ──
REDIS_URL=redis://localhost:6379

# ── Server ──
PORT=3001
CLIENT_URL=http://localhost:5173

# ── Frontend ──
VITE_API_URL=http://localhost:3001/api
VITE_WS_URL=http://localhost:3001

Production Notes

• On Railway, set environment variables in the service's Variables tab

• DATABASE_URL is automatically provided when you link a Railway PostgreSQL service

• Never commit .env files to git: they're in .gitignore