SMTP HTTP Proxy

A lightweight, stateless SMTP HTTP proxy built with Bun/TypeScript/ElysiaJS.

Features

• Multiple SMTP providers with automatic failover
• API key authentication via Bearer tokens
• Full email support: text, HTML, CC, BCC, attachments
• Rate limiting per API key
• Stateless: No database required
• Docker-ready: Easy self-hosting

Quick Start

Environment Variables

# Required
CORS_ORIGIN=http://localhost:3000
DATABASE_URL=postgres://localhost:5432/dummy # Required by @stem/env, can be dummy
API_KEYS=sk-key-1,sk-key-2 # Comma-separated API keys# SMTP providers (JSON array)
SMTP_PROVIDERS=[{
"name": "gmail",
"host": "smtp.gmail.com",
"port": 587,
"secure": false,
"auth": {
"user": "your-email@gmail.com",
"pass": "your-app-password"
}
}]
# Optional
MAX_ATTACHMENT_SIZE=10MB # Default: 10MB
RATE_LIMIT_PER_MINUTE=60 # Default: 60 requests/minute

Docker Deployment

docker-compose up -d

API Usage

Send Email:

curl -X POST http://localhost:3000/v1/send \
-H "Authorization: Bearer your-api-key" \
-H "Content-Type: application/json" \
-d '{ "to": "recipient@example.com", "subject": "Hello", "text": "Plain text body", "html": "<h1>HTML body</h1>" }'

Health Check:

curl http://localhost:3000/v1/health \
-H "Authorization: Bearer your-api-key"

API Endpoints

Endpoint	Method	Description
/	GET	Service status
/v1/send	POST	Send email
/v1/health	GET	Provider health status

Email Payload Schema

{
to: string|string[];// Required
from?: string;// Optional
subject: string;// Required
text?: string;// Plain text body
html?: string;// HTML body
cc?: string|string[];// CC recipients
bcc?: string|string[];// BCC recipients
replyTo?: string;// Reply-to address
attachments?: Array<{// Base64 encoded attachmentsfilename: string;content: string;// Base64contentType?: string;}>;}

Response Format

Success (200):

{
"success": true,
"messageId": "<...>",
"provider": "gmail",
"accepted": ["recipient@example.com"],
"rejected": []
}

Error (400/401/429/500):

{
"success": false,
"error": "Error description"
}