Mailflow

A modern, self-hosted email client powered by Resend.

Mailflow is a self-hosted Resend inbox and email client built with Next.js. It provides a polished webmail experience for receiving, reading, organizing, and sending email from your own domain.

Features

• Send and receive email through the Resend API
• Render responsive HTML emails in an adaptive dark reader
• Persistent read/unread state, stars, folders, labels, and drafts
• Inbox, Unread, Starred, Sent, Archive, Spam, and Trash views
• Cursor-based pagination and page-level search
• Shareable folder and message URLs
• Secure single-admin authentication
• Responsive desktop and mobile interface
• Production-ready deployment on Vercel

Stack

• Next.js 16, React 19, and TypeScript
• Resend Sending and Receiving APIs
• PostgreSQL with Prisma
• Neon or Vercel Postgres
• Vercel hosting

Quick start

Requirements: Node.js 20+, a Resend account with a receiving domain, and a PostgreSQL database.

npm install
cp .env.example .env.local
npm run auth:hash -- "your-password"
npm run db:deploy
npm run dev

Open http://localhost:3000.

Environment

RESEND_API_KEY=re_your_api_key
RESEND_FROM_EMAIL=Mailflow <mail@your-verified-domain.com>
DATABASE_URL=postgresql://user:password@host/database?sslmode=require
ADMIN_EMAIL=admin@example.com
ADMIN_PASSWORD_HASH=$2b$12$replace_with_bcrypt_hash
AUTH_SECRET=replace_with_a_long_random_secret

Generate ADMIN_PASSWORD_HASH with npm run auth:hash -- "your-password". Use a long random value for AUTH_SECRET.

Configure Resend

1. Verify a sending domain in Resend.
2. Configure the domain's MX record for inbound email.
3. Create an API key with sending and receiving access.
4. Set RESEND_FROM_EMAIL to an address on the verified domain.

Resend remains the source of message content. PostgreSQL stores client-specific state such as read status, folders, stars, labels, and drafts.

Deploy to Vercel

1. Create a Neon or Vercel Postgres database.
2. Import the repository into Vercel.
3. Add every variable from .env.example.
4. Run npm run db:deploy against the production database.
5. Deploy.

Routes

• /inbox, /sent, /archive, and other mailbox folders
• /mail/[id] for reloadable message links
• /label/[id] for label views

Development

npm run lint
npm run build
npm run db:studio

Security

• Resend and database credentials remain server-side.
• Authentication uses a signed, HttpOnly session cookie.
• Received HTML is rendered in a sandboxed iframe.
• Tracking pixels are removed from displayed messages.