SMTPy for Developers: Email Infrastructure as Code

Why Developers Choose SMTPy

Email in applications is traditionally painful: SendGrid for transactional, Postfix for receiving, a third-party service for aliases... SMTPy consolidates all of it into one coherent API.

REST API Examples

Create an alias

curl -X POST https://smtpy.fr/api/v1/aliases \
  -H "X-API-Key: your-api-key" \
  -H "Content-Type: application/json" \
  -d '{"local": "user-123", "domain_id": 1, "forward_to": "user@example.com"}'

List messages for an alias

curl https://smtpy.fr/api/v1/messages?alias_id=42 \
  -H "X-API-Key: your-api-key"

Webhooks: Real-time Email Processing

Register a webhook URL and receive a POST on every inbound email:

// Payload delivered to your endpoint
{
  "event": "email.received",
  "alias": "contact@yourdomain.com",
  "from": "client@example.com",
  "subject": "New order #4521",
  "body_text": "Hello...",
  "received_at": "2026-03-10T14:23:00Z"
}

MCP Server: AI-Assisted Email Management

SMTPy ships an MCP Server compatible with Claude, GPT-4o, and other LLMs. Your AI assistants can:

• Read and summarize incoming emails
• Create aliases on demand
• Analyze delivery statistics
• Reply to emails directly from the assistant

Add to claude_desktop_config.json:

{
  "mcpServers": {
    "smtpy": {
      "command": "npx",
      "args": ["-y", "smtpy-mcp"],
      "env": {
        "SMTPY_API_KEY": "your-api-key",
        "SMTPY_URL": "https://smtpy.fr"
      }
    }
  }
}

Per-User Aliases in SaaS Apps

Provision a dedicated inbox for each user at signup:

# Python — create alias on user registration
import httpx

def create_user_email(username: str, user_email: str) -> str:
    resp = httpx.post(
        "https://smtpy.fr/api/v1/aliases",
        headers={"X-API-Key": SMTPY_API_KEY},
        json={
            "local": username,
            "domain_id": YOUR_DOMAIN_ID,
            "forward_to": user_email
        }
    )
    return f"{username}@yourdomain.com"

Isolated Email Testing in CI/CD

Create throwaway aliases per test run so CI email tests never touch production inboxes:

• test-signup-{RUN_ID}@yourdomain.com — test the registration flow
• test-reset-{RUN_ID}@yourdomain.com — test password reset
• Disable or delete test aliases at the end of the pipeline

SMTPy's API makes this a two-liner in any CI environment.