Outlet.sh

The modern, self-hosted email platform for indie hackers and creators. Marketing campaigns, transactional emails, and AI-powered automation—all in a single binary.

Why Outlet.sh?

Single binary deployment — No PHP, no external database. Just download and run.
SQLite with WAL mode — Zero configuration, handles 100k+ subscribers.
Marketing + Transactional — One platform for newsletters and application emails.
AI-native MCP integration — Build email sequences by talking to Claude.
Built-in backup system — One-click download or automated S3 backups.
Full source code included — No obfuscation, modify anything you need.
SMTP ingress server — Drop-in replacement for any SMTP setup. Point Postfix, your app, or any mail client at Outlet.

Quick Start

Option 1: Direct Binary

# Download the binary for your platform
wget https://outlet.sh/download/outlet-linux-amd64
chmod +x outlet-linux-amd64

# Set required environment variables
export JWT_SECRET="your-secret-key-here"
export JWT_REFRESH_SECRET="your-refresh-secret-here"
export ADMIN_EMAIL="admin@example.com"
export ADMIN_PASSWORD="your-admin-password"

# Run it
./outlet-linux-amd64

Open http://localhost:9888 and log in with your admin credentials.

Option 2: Docker Compose

Create a .env file:

# .env
JWT_SECRET=your-secret-key-here
JWT_REFRESH_SECRET=your-refresh-secret-here
ENCRYPTION_KEY=your-32-byte-hex-key
PRODUCTION_MODE=true
APP_DOMAIN=mail.yourdomain.com
APP_BASE_URL=https://mail.yourdomain.com

Create compose.yaml:

services:
  outlet:
    image: ghcr.io/outlet-sh/outlet:latest
    ports:
      - "443:443"
      - "80:80"
      - "587:587"
    volumes:
      - ./data:/app/data
    env_file: .env
    restart: always

docker compose up -d

Option 3: Systemd Service

Create /etc/systemd/system/outlet.service:

[Unit]
Description=Outlet.sh Email Platform
After=network.target

[Service]
Type=simple
User=outlet
WorkingDirectory=/opt/outlet
ExecStart=/opt/outlet/outlet
Restart=always
RestartSec=5
EnvironmentFile=/opt/outlet/.env

[Install]
WantedBy=multi-user.target

sudo systemctl enable outlet
sudo systemctl start outlet

Features

Subscriber Management

CSV import/export
Custom fields and tags
Segmentation and filtering
Double opt-in flow
Automatic bounce/complaint handling
GDPR compliance tools

Marketing Campaigns

Rich text and HTML editor
Template library
Broadcast and scheduled campaigns
RSS-to-email campaigns
Open/click tracking
Per-campaign analytics

Transactional Email API

REST API for application emails
Template-based messages with merge fields
Dedicated sending queue (separate from marketing)
Per-template analytics
Webhook callbacks for delivery events
Auto-generated SDKs (TypeScript, Python, Go, PHP)

SMTP Ingress Server

Send emails through Outlet using standard SMTP protocol — a 100% drop-in replacement for any existing SMTP setup. Point your application, Postfix relay, or any mail client at Outlet and get all the platform features automatically.

Authentication:

Username: Your brand slug (e.g., my-company)
Password: Your brand's API key

The username must match the brand slug associated with your API key. This enforces brand isolation and prevents cross-brand sending.

Custom Headers for advanced control:

Header	Purpose	Example
`X-Outlet-List`	Associate with a list	`newsletter`
`X-Outlet-Tags`	Comma-separated tags	`welcome,onboarding`
`X-Outlet-Template`	Use a template	`order-confirmation`
`X-Outlet-Type`	`marketing` or `transactional`	`transactional`
`X-Outlet-Track`	`opens,clicks` or `none`	`opens,clicks`
`X-Outlet-Meta-*`	Custom metadata	`X-Outlet-Meta-OrderID: 12345`

Example with swaks:

swaks --to user@example.com \
      --from hello@yourdomain.com \
      --server mail.yourdomain.com:587 \
      --auth PLAIN \
      --auth-user my-brand \
      --auth-password "your-api-key" \
      --tls \
      --header "X-Outlet-List: customers" \
      --header "X-Outlet-Tags: purchase,vip" \
      --body "Thanks for your order!"

Example with Python:

import smtplib
from email.mime.text import MIMEText

msg = MIMEText("<h1>Welcome!</h1><p>Thanks for signing up.</p>", "html")
msg["Subject"] = "Welcome to our platform"
msg["From"] = "hello@yourdomain.com"
msg["To"] = "user@example.com"
msg["X-Outlet-List"] = "newsletter"
msg["X-Outlet-Tags"] = "welcome,new-user"

with smtplib.SMTP("mail.yourdomain.com", 587) as server:
    server.starttls()
    server.login("my-brand", "your-api-key")
    server.send_message(msg)

Configuration via Environment Variables (recommended for Docker):

SMTP_ENABLED=true              # Enable SMTP server
SMTP_PORT=587                  # Standard submission port (default: 587)
SMTP_ALLOW_INSECURE_AUTH=true  # Allow AUTH without TLS (for testing/internal use)
SMTP_TLS_CERT=/path/to/cert.pem   # TLS certificate (optional)
SMTP_TLS_KEY=/path/to/key.pem     # TLS private key (optional)

Docker Compose example with SMTP:

Create a .env file:

# .env
JWT_SECRET=your-secret-key-here
JWT_REFRESH_SECRET=your-refresh-secret-here
ENCRYPTION_KEY=your-32-byte-hex-key
PRODUCTION_MODE=true
APP_DOMAIN=mail.yourdomain.com
APP_BASE_URL=https://mail.yourdomain.com

# SMTP Configuration
SMTP_ENABLED=true
SMTP_PORT=587
SMTP_ALLOW_INSECURE_AUTH=false
SMTP_TLS_CERT=/app/certs/cert.pem
SMTP_TLS_KEY=/app/certs/key.pem

Create compose.yaml:

services:
  outlet:
    image: ghcr.io/outlet-sh/outlet:latest
    ports:
      - "443:443"
      - "80:80"
      - "587:587"     # SMTP submission port
    volumes:
      - ./data:/app/data
      - ./certs:/app/certs
    env_file: .env
    restart: always

Configuration via YAML (for direct binary):

# In etc/outlet.yaml
SMTP:
  enabled: "true"
  port: "587"
  tlscert: /path/to/cert.pem
  tlskey: /path/to/key.pem
  allowinsecureauth: "false"   # Set to "true" only without TLS

Testing with curl:

curl -v --url 'smtp://mail.yourdomain.com:587' \
  --mail-from 'hello@yourdomain.com' \
  --mail-rcpt 'recipient@example.com' \
  --user 'my-brand:your-api-key' \
  --upload-file - <<< "Subject: Test Email

This is a test email sent via Outlet SMTP."

Note: For production use, always configure TLS certificates. The SMTP_ALLOW_INSECURE_AUTH=true option should only be used for testing or when running behind a TLS-terminating proxy.

Automation

Autoresponder sequences
Trigger rules (tag added, link clicked, date-based)
Transactional-to-marketing handoff

AI-Powered Email (MCP Integration)

Outlet.sh includes a built-in MCP server, enabling AI assistants like Claude to manage your email operations:

You: "Create a 7-day welcome sequence for my SaaS. Day 1 introduces
     the product, Day 3 covers the main feature, Day 5 shares a case
     study, Day 7 offers a discount."

Claude: [Creates sequence, adds emails with proper delays, writes
        copy, sets triggers — all via MCP tools]

MCP capabilities include:

List and subscriber management
Campaign creation and scheduling
Sequence building with email content
Analytics queries and insights
Transactional email sending

Backup System

Dashboard download — One-click database backup
S3 automated backup — Scheduled backups with retention policies
CLI backup — outlet backup or outlet backup --s3
Safe live backups — Uses SQLite backup API (no corruption)
Easy restore — Replace file and restart, or use dashboard

Configuration

Configuration uses environment variables. Create a .env file or set them directly:

Required

Variable	Description
`JWT_SECRET`	Secret key for access tokens
`JWT_REFRESH_SECRET`	Secret key for refresh tokens
`ADMIN_EMAIL`	Super admin email (created on first startup)
`ADMIN_PASSWORD`	Super admin password

Production

Variable	Description
`PRODUCTION_MODE`	Set to `true` for HTTPS/Let's Encrypt
`BEHIND_PROXY`	Set to `true` when a load balancer or ingress terminates TLS: plain HTTP on port 8888 with the embedded UI, no Let's Encrypt
`APP_DOMAIN`	Your domain (e.g., `mail.yourdomain.com`)
`APP_BASE_URL`	Full URL (e.g., `https://mail.yourdomain.com`)

Optional

Variable	Description
`DATABASE_PATH`	SQLite path (default: `./data/outlet.db`)
`ENCRYPTION_KEY`	32-byte hex key for credential encryption
`ANTHROPIC_API_KEY`	Claude AI integration
`STRIPE_SECRET_KEY`	Payment processing
`STRIPE_WEBHOOK_SECRET`	Stripe webhook verification

SMTP Ingress Server

Variable	Description
`SMTP_ENABLED`	Set to `true` to enable SMTP server
`SMTP_PORT`	SMTP port (default: `587`)
`SMTP_TLS_CERT`	Path to TLS certificate file
`SMTP_TLS_KEY`	Path to TLS private key file
`SMTP_ALLOW_INSECURE_AUTH`	Set to `true` to allow AUTH without TLS (testing only)

Amazon SES Setup

Outlet.sh works best with Amazon SES for cost-effective sending (~$0.10 per 1,000 emails).

Create SES credentials in AWS Console → SES → SMTP Settings
Verify your domain in SES → Verified Identities
Configure in Outlet.sh dashboard → Settings → Email Provider
Request production access if still in SES sandbox

API & SDKs

Outlet.sh provides a REST API with auto-generated clients:

Transactional Email Example (TypeScript)

import { Outlet } from '@outlet/sdk';

const outlet = new Outlet('your-api-key', 'https://mail.yourdomain.com');

await outlet.emails.sendEmail({
  to: 'user@example.com',
  template_slug: 'welcome-email',
  variables: {
    name: 'John',
    activation_link: 'https://...'
  }
});

Transactional Email Example (Go)

import "github.com/outlet-sh/outlet/sdk/go"

client := outlet.NewClient("your-api-key", "https://mail.yourdomain.com")

err := client.Emails.SendEmail(ctx, outlet.SendEmailRequest{
    To:           "user@example.com",
    TemplateSlug: "welcome-email",
    Variables: map[string]string{
        "name":            "John",
        "activation_link": "https://...",
    },
})

Architecture

┌───────────────────────────────────────────────────────────────────┐
│                         Single Binary                              │
├───────────────────────────────────────────────────────────────────┤
│  ┌───────────┐  ┌───────────┐  ┌───────────┐  ┌───────────────┐   │
│  │ SvelteKit │  │  go-zero  │  │   SMTP    │  │  MCP Server   │   │
│  │ Frontend  │  │  REST API │  │  Ingress  │  │ (AI Integration)│  │
│  └───────────┘  └───────────┘  └───────────┘  └───────────────┘   │
├───────────────────────────────────────────────────────────────────┤
│  ┌───────────────┐  ┌───────────────┐  ┌───────────────────────┐  │
│  │ Email Workers │  │ Rules Engine  │  │  Webhook Dispatcher   │  │
│  └───────────────┘  └───────────────┘  └───────────────────────┘  │
├───────────────────────────────────────────────────────────────────┤
│                       SQLite (WAL Mode)                            │
│                       ./data/outlet.db                             │
└───────────────────────────────────────────────────────────────────┘

Frontend: Embedded SvelteKit 5 static build
REST API: go-zero framework with auto-generated handlers
SMTP Ingress: Standard SMTP server (port 587) for drop-in integration
Database: SQLite with WAL mode, auto-migrations on startup
Workers: Background email sending with rate limiting
MCP: Model Context Protocol server for AI assistants

Development

Prerequisites

Go 1.21+
Node.js 20+
pnpm

Setup

# Clone the repository
git clone https://github.com/outlet-sh/outlet
cd outlet

# Install dependencies
go mod download
cd app && pnpm install && cd ..

# Create .env file
cp .env.example .env
# Edit .env with your values

# Run backend (uses air for hot reload)
make run

# In another terminal, run frontend
cd app && pnpm dev

Build

# Build Go binary
make build

# Build frontend
cd app && pnpm build

# The binary embeds the frontend automatically

Code Generation

# After modifying outlet.api
make gen          # Regenerates handlers, types, and TS client

# After modifying SQL queries
make sqlc-gen     # Regenerates type-safe Go from SQL

# All code generation
make gen-all

Testing

# Go tests
go test ./...
go test ./internal/services/emailval/   # Single package
go test -run TestName ./internal/...    # Single test

# Frontend tests
cd app && pnpm test

License

Outlet is open source under the AGPL-3.0 License.

Self-host freely for personal or commercial use
Modifications must be shared under AGPL if distributed or offered as a service
Commercial licensing available for companies needing different terms

Support

Documentation: https://outlet.sh/docs
Issues: https://github.com/outlet-sh/outlet/issues
Email: support@outlet.sh

Built with care for indie hackers who value simplicity, ownership, and modern tooling.

Name		Name	Last commit message	Last commit date
.github/workflows		.github/workflows
app		app
cmd		cmd
etc		etc
internal		internal
.air.toml		.air.toml
.dockerignore		.dockerignore
.env.example		.env.example
.gitignore		.gitignore
CLAUDE.md		CLAUDE.md
Dockerfile		Dockerfile
LICENSE		LICENSE
Makefile		Makefile
README.md		README.md
compose.yaml		compose.yaml
go.mod		go.mod
go.sum		go.sum
outlet.api		outlet.api
outlet.go		outlet.go
setup.sh		setup.sh
sqlc.yaml		sqlc.yaml

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Outlet.sh

Why Outlet.sh?

Quick Start

Option 1: Direct Binary

Option 2: Docker Compose

Option 3: Systemd Service

Features

Subscriber Management

Marketing Campaigns

Transactional Email API

SMTP Ingress Server

Automation

AI-Powered Email (MCP Integration)

Backup System

Configuration

Required

Production

Optional

SMTP Ingress Server

Amazon SES Setup

API & SDKs

Transactional Email Example (TypeScript)

Transactional Email Example (Go)

Architecture

Development

Prerequisites

Setup

Build

Code Generation

Testing

License

Support

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