Elysia Template

Type-safe Bun API template built with Elysia, Better Auth, Drizzle, Postgres, and Redis.

Stack

• Bun
• Elysia
• Better Auth
• Drizzle ORM
• PostgreSQL
• Redis
• OpenAPI via @elysia/openapi
• OpenTelemetry
• Oxlint + TypeScript strict mode

Features

• Typed environment loading in src/start/env.ts
• Session-based auth with Better Auth
• Todo CRUD module
• OpenAPI docs at /docs
• Redis-backed Drizzle cache integration
• Strict TypeScript and lint rules

Requirements

• Bun
• PostgreSQL
• Redis

Environment Variables

Create a .env file with:

DATABASE_URL=postgres://user:password@localhost:5432/app
REDIS_URL=redis://localhost:6379

These are validated on startup by src/start/env.ts.

Install

bun install

Run

bun run dev

The app listens on http://localhost:3000.

Docker

Build the image:

docker build -t elysia-template .

Run the container:

docker run --rm -p 3000:3000 \
  -e DATABASE_URL="postgres://user:password@host.docker.internal:5432/app" \
  -e REDIS_URL="redis://host.docker.internal:6379" \
  elysia-template

The container includes a healthcheck against GET /.

Scripts

• bun run dev - start the app in watch mode
• bun run build - build the server binary
• bun run lint - run oxlint
• bun run lint:fix - run oxlint with fixes
• bun run format - format the repo
• bun run format:check - check formatting
• bun run check - format, lint, and build

API

Health

• GET / - health check

Auth

• Better Auth routes are mounted under /auth
• OpenAPI auth paths are exposed under /auth/api

Todos

All todo routes require authentication.

• GET /todos - list current user todos
• POST /todos - create a todo
• PUT /todos/:id - replace a todo
• PATCH /todos/:id - partially update a todo
• DELETE /todos/:id - delete a todo

OpenAPI Docs

• UI: http://localhost:3000/docs
• JSON: http://localhost:3000/docs/json

Project Structure

src/
  contracts/     Shared abstractions and errors
  adapters/      External integrations like Redis and Drizzle cache
  modules/       Feature modules such as todo and healthcheck
  start/         App bootstrap, auth, db, cache, env
  utils/         Shared helpers

Notes

• Todo not-found cases return 404
• The app uses a typed env object instead of reading process.env throughout the codebase
• Better Auth OpenAPI output is merged into the main Elysia OpenAPI document