A self-hosted cold email sender built with SvelteKit. Manage contact lists, create email templates with dynamic variables, and send personalized bulk emails. Easy to setup and free to fork.

• Contact Lists — Currently supporting CSV imports; Import contacts via CSV and map the fields; you can later add-on contacts manually trough UI
• Email Templates — Create reusable templates with variables like {{firstName}}, {{company}}, {{industry}}, format them using html tags, etc.
• Bulk Sending — Select contacts, pick a template, and send personalized emails
• Per-user SMTP — Each user configures their own SMTP credentials (encrypted at rest)
• Authentication — Email/password auth with email verification via Better Auth

• Frontend: SvelteKit & Tailwind CSS + DaisyUI
• Database: PostgreSQL via Prisma ORM
• Auth: Better Auth
• Email: Nodemailer

• Bun (recommended) or Node.js 20+
• PostgreSQL database
• SMTP server for sending verification and outbound emails

git clone https://github.com/your-username/cold0.git
cd cold0
bun install

Copy the example env file and fill in your values:

cp .env.example .env

The SYSTEM prefixed ones are used for sending verification emails upon registration

To generate random secrets:

openssl rand -base64 32

bunx prisma migrate dev
bunx prisma generate

bun dev

Open http://localhost:5173.

1. Register at /register
2. Check your email for the verification link
3. Verify and log in
4. Go to Settings and configure your SMTP credentials for sending emails

When deploying make sure your build script is configured to generate prisma client and run migrations, like so: prisma generate && prisma migrate deploy && vite build

The app can be deployed anywhere that runs Node.js/Bun — VPS with Coolify, Docker, Vercel, etc.

Make sure to:

• Set BETTER_AUTH_URL to your production domain
• Use strong, unique values for BETTER_AUTH_SECRET and ENCRYPTION_KEY
• Use SSL/TLS for your PostgreSQL connection in production

MIT