📩 Mailer Service

A flexible Node.js email service using Brevo (formerly Sendinblue) and fallback SMTP (e.g., Gmail) with smart routing logic. Supports daily email tracking and dynamic provider control via API.

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✨ Features

• 📤 Send OTPs and transactional emails via Brevo or fallback email (like Gmail).
• 📦 JSON-based API with sender-level override support.
• 🔄 Daily email count tracked (extendable to limits, quotas, stats).
• 🛠 Built-in fallback mechanism for reliability.
• 🔒 Secure using .env and nodemailer.
• 🧰 Ready to deploy anywhere: Railway, Render, Vercel Serverless, etc.

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🚀 Getting Started

1. Clone the Repo

git clone https://github.com/priyeshjaiswal/free-node-mailer.git
cd free-node-mailer

2. Install Dependencies

npm install

3. Setup .env

Create a .env file at the root:

PORT=5000

# BREVO credentials (https://www.brevo.com)
BREVO_HOST=smtp-relay.brevo.com
BREVO_PORT=587
BREVO_SECURE=false
BREVO_USER=your_brevo_login_email
BREVO_PASS=your_brevo_smtp_key

# Fallback (Gmail or other SMTP)
FALLBACK_HOST=smtp.gmail.com
FALLBACK_PORT=465
FALLBACK_USER=your_gmail_address
FALLBACK_PASS=your_app_password

FROM_EMAIL=no-reply@yourcompany.com
DAILY_LIMIT=300

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📝 API Endpoint

POST /send

Sends an email using either:

• provider = "bravo" → Brevo
• provider = "email" → Fallback (like Gmail)
• If sender.email is provided, it overrides everything.

📌 JSON Body Format

{
  "provider": "bravo", // or "email"
  "to": "user@example.com",
  "subject": "Your OTP Code",
  "html": "<p>Your OTP is <strong>123456</strong>. Valid for 5 minutes.</p>",
  "sender": {
    "name": "OTP Service",
    "email": "no-reply@yourcomapny.com"
  }
}

🧠 Logic Explained

Rule	Behavior
sender.email exists	Always use Brevo
provider === "bravo"	Use Brevo
provider === "email"	Use Fallback
None/Unknown provider	Returns error

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✅ Sample CURL Usage

curl -X POST http://localhost:5000/send \
  -H "Content-Type: application/json" \
  -d '{
    "provider": "bravo",
    "to": "receiveremail@gmail.com",
    "subject": "OTP Code",
    "html": "<p>Your OTP is <strong>000000</strong>.</p>",
    "sender": {
      "name": "OTP",
      "email": "no-reply@yourcomapny.com"
    }
  }'

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🧾 Register on Brevo (Sendinblue)

1. Go to https://www.brevo.com and sign up.
2. Verify your account using business email and domain.
3. Go to SMTP & API → SMTP section:
   • Click on "Create SMTP Key".
   • Copy the key and use it in your .env as BREVO_PASS.
4. Set BREVO_USER as your Brevo login email.
5. Brevo SMTP host: smtp-relay.brevo.com
6. Port: 587, Secure: false

⚠️ You may need to verify your sending domain (no-reply@yourcompany.com) under Settings > Senders > Domains.

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🔄 Daily Counter

The service maintains a file email_count.json to reset and track how many emails are sent per day (can be extended to DB or metrics dashboards).