hono-openapi-rpc

A modern monorepo for building full-stack applications with Bun, Hono, OpenAPI, and TanStack Router. This project is organized as a Bun workspace with separate API and Web applications, plus a shared schema package.

Project Structure

hono-openapi-rpc/
  apps/
    api/      # Hono-based API server (OpenAPI, Zod, Bun)
    web/      # React web app (Vite, TanStack Router, Tailwind CSS)
  packages/
    db/       # Shared Drizzle ORM schema and database client for the monorepo
  package.json
  README.md
  bun.lock
  tsconfig.json

Prerequisites

• Bun v1.2.17 or later
• Node.js (for some tooling, optional)
• Git
• TypeScript (peer dependency)
• Neon project for the PostgreSQL database
• GitHub OAuth app (for authentication) (create one here)

Getting Started

Install all dependencies for all workspaces:

bun install

Running the Applications

API Server

Runs the Hono API server (on port 4000 by default):

bun run api

• Source: apps/api
• Main entry: src/index.ts
• Serves OpenAPI endpoints under /api
• Serves static files from apps/api/public for non-API routes

Web App

Runs the React web app (Vite dev server on port 3000):

bun run web

• Source: apps/web
• Main entry: src/main.tsx
• Uses TanStack Router, React Query, Tailwind CSS, and shadcn/ui
• Proxies API requests to the API server

Building for Production

Build the web app (output to apps/api/public for static serving):

bun run build

Starting in Production

Start the API server (serves both API and built static web):

bun run start

Workspace Scripts

From the root, you can use these scripts:

Script	Description
api	Run the API server in dev mode
web	Run the web app in dev mode
build	Build the web app for production
start	Start the API server (serves static + API)
db:generate	Generate database migrations (from packages/db)
db:migrate	Run database migrations (from packages/db)
db:push	Push schema changes to the database (from packages/db)
db:studio	Open database studio UI (from packages/db)
test	Run API tests (from apps/api)
format	Format codebase using Biome/Ultracite

Packages

apps/api

• Hono v4 (API framework)
• Zod (validation)
• OpenAPI (via @hono/zod-openapi)
• Serves static files from public/
• Exposes OpenAPI docs and reference
• Uses Bun for fast startup

apps/web

• React 19
• Vite 6
• TanStack Router & Query
• Tailwind CSS 4
• shadcn/ui components
• Proxies /api requests to the API server

packages/db

• Shared Drizzle ORM schema and database client for the monorepo
• Provides schema definitions for users, notes, accounts, sessions, and verification
• Exports Zod schemas for type-safe validation and OpenAPI generation
• Used by both API and Web for consistent data modeling and validation

Development Notes

• All apps and packages use TypeScript modules.
• Use bun install to install dependencies across all workspaces.
• The web app builds to apps/api/public for seamless static serving by the API server.
• API routes are namespaced under /api (see BASE_PATH).
• Static files are served for all other routes.

Customization

• Add new API endpoints in apps/api/src/routes/
• Add new React routes in apps/web/src/routes/
• Add or update shared schemas in packages/schema/

Acknowledgements

• Bun
• Hono
• TanStack Router
• Zod
• shadcn/ui
• Tailwind CSS
• Neon
• better-auth