API v1.0

SendPigeon Documentation

Everything you need to send transactional emails. SDKs for Node.js, Python, Go, PHP and REST API.

SMTP Relay

Send emails via standard SMTP. Works with any language, framework, or legacy system.

Standard SMTP. Connect to smtp.sendpigeon.dev:587 with STARTTLS and your API key. Same deliverability, same tracking, same pipeline as the REST API.

Connection Details

Host	smtp.sendpigeon.dev
Port	587
Encryption	STARTTLS (required)
Username	apikey
Password	Your API key (`sk_live_...`)
Max message	25 MB

Quick Test

Verify your setup with swaks (Swiss Army Knife for SMTP):

Terminalbash

swaks --server smtp.sendpigeon.dev:587 --tls \
  --auth-user apikey --auth-password sk_live_xxx \
  --from hello@yourdomain.com --to test@example.com \
  --header "Subject: Test SMTP" --body "Hello from SMTP"

Node.js (Nodemailer)

TypeScripttypescript

import nodemailer from "nodemailer";
 
const transport = nodemailer.createTransport({
  host: "smtp.sendpigeon.dev",
  port: 587,
  secure: false,
  auth: {
    user: "apikey",
    pass: process.env.SENDPIGEON_API_KEY,
  },
});
 
await transport.sendMail({
  from: "Acme <hello@yourdomain.com>",
  to: "user@example.com",
  subject: "Welcome!",
  html: "<h1>Hello from SMTP</h1>",
});

Python

Pythonpython

import smtplib
from email.mime.text import MIMEText
 
msg = MIMEText("<h1>Hello from SMTP</h1>", "html")
msg["From"] = "Acme <hello@yourdomain.com>"
msg["To"] = "user@example.com"
msg["Subject"] = "Welcome!"
 
with smtplib.SMTP("smtp.sendpigeon.dev", 587) as server:
    server.starttls()
    server.login("apikey", "sk_live_xxx")
    server.send_message(msg)

Ruby (Action Mailer)

Rubyruby

# config/environments/production.rb
config.action_mailer.smtp_settings = {
  address: "smtp.sendpigeon.dev",
  port: 587,
  user_name: "apikey",
  password: ENV["SENDPIGEON_API_KEY"],
  authentication: :plain,
  enable_starttls_auto: true,
}

PHP (Laravel)

.envbash

# .env
MAIL_MAILER=smtp
MAIL_HOST=smtp.sendpigeon.dev
MAIL_PORT=587
MAIL_USERNAME=apikey
MAIL_PASSWORD=sk_live_xxx
MAIL_ENCRYPTION=tls

Go

Gogo

package main
 
import (
    "net/smtp"
)
 
func main() {
    auth := smtp.PlainAuth("", "apikey", "sk_live_xxx", "smtp.sendpigeon.dev")
 
    msg := []byte("From: hello@yourdomain.com\r\n" +
        "To: user@example.com\r\n" +
        "Subject: Welcome!\r\n" +
        "Content-Type: text/html\r\n" +
        "\r\n" +
        "<h1>Hello from SMTP</h1>")
 
    smtp.SendMail("smtp.sendpigeon.dev:587", auth,
        "hello@yourdomain.com", []string{"user@example.com"}, msg)
}

Tracking via Headers

Control open and click tracking per-message using custom headers. These headers are stripped before delivery.

Header	Values	Default
X-SP-Track-Opens	`true` / `false`	No tracking
X-SP-Track-Clicks	`true` / `false`	No tracking

Custom Headers

The same custom headers allowed via REST API work over SMTP. X-* headers and List-* headers are forwarded. Standard envelope headers (From, To, Subject, etc.) are handled automatically.

Same pipeline. SMTP messages go through the same validation, domain verification, rate limiting, and delivery pipeline as the REST API. Logs, webhooks, and analytics work identically.