What This Feature Does
The Transactional Email add-on lets you send automated, event-triggered emails like registration confirmations, password resets, OTPs, purchase receipts, and shipping notifications directly from your application via API.
When You Need This
Use transactional emails when you need to send time-sensitive, personalized messages triggered by user actions in your app or website. These are different from marketing campaigns because they're expected by the recipient and typically required for your service to function.
Examples of transactional emails:
Account registration confirmations
Password reset requests
One-time passwords (OTPs) or verification codes
Order confirmations and receipts
Shipping and delivery notifications
Invoice and billing updates
Account alerts and security notifications
Before You Begin
Plan Requirements:
The Transactional Email add-on is available only on paid plans (not available on the Free tier)
Pricing:
Base fee: $10/month (includes 3,000 emails)
Additional emails: $0.003 per email
Billing is usage-based and generated after you send emails
Technical Requirements:
You must have a verified/whitelisted domain in SendX before you can send transactional emails
Your development team will need to integrate our REST API into your application
Step-by-Step Setup Guide
Step 1: Enable the Transactional Email Add-On
Click on your profile icon in the top navigation bar
Select Settings from the dropdown menu
In the left sidebar, click on Add-ons
Scroll to find Transactional Email in the add-ons list
Toggle the switch to enable the add-on
Note: Enabling the add-on does not immediately start charging you. Billing begins only when you start sending emails through the API.
Step 2: Get Your API Credentials
While still in Settings, go to Add-ons
Click on Transactional Email
Click the Settings button (or gear icon)
You'll see your Team API Key displayed here
Copy and securely store this API key. you'll need it to authenticate API requests from your application
Important Security Notes:
Your API key is shared at the team level
Never expose this API key in client-side code or public repositories
If your API key is compromised, contact SendX support immediately to regenerate it
Step 3: Access API Documentation
Click on Settings in the top navigation bar
Scroll down to the API Documentation section
Click Open Documentation
This opens the complete REST API reference with:
Available endpoints
Request/response formats
Authentication methods
Code examples
Step 4: Integrate the API Into Your Application
Work with your development team to integrate SendX's REST API into your application. Your developers will:
Use the Team API Key for authentication
Call the endpoint when transactional emails need to be sent
Handle any errors or failed requests (SendX does not automatically retry failed sends)
Optionally, implement retry logic in your application for critical emails
Step 5: Monitor Email Activity
After your integration is live, you can track all transactional email activity:
View Logs (Detailed Records)
Click Analytics in the top navigation bar
Under the Analytics section, click Logs
Here you'll see a detailed log of every transactional email sent, including:
Recipient email address
Timestamp
Delivery status (sent, delivered, bounced, failed)
Error messages (if any)
View Analytics (Overall Performance)
Click Analytics in the top navigation bar
Transactional email metrics are displayed separately from your marketing campaign stats
You can see:
Total emails sent
Delivery rates
Bounce rates
Overall performance trends
Important Notes & Limitations
Domain Verification is Required
You cannot send transactional emails until you have a verified/whitelisted domain in SendX. If you try to send emails without domain verification, your API requests will fail.
How to verify your domain:
Go to Settings → Domains → Add and verify your sending domain
Follow the DNS setup instructions provided
Transactional vs. Marketing Emails
Do not use the Transactional Email add-on for marketing campaigns. This add-on is strictly for service-related, user-triggered emails.
Transactional:
Password resets
Order confirmations
Shipping updates
Account alerts
OTPs and verification codes
Marketing:
Promotional newsletters
Product announcements
Sales offers
Marketing drip campaigns
Violating this can harm your sender reputation and may result in account suspension.
Unsubscribed Users Can Receive Transactional Emails
Transactional emails can be sent to contacts who have unsubscribed from your marketing emails. This is legally permitted because transactional emails are expected and necessary for your service.
However: Do not abuse this. Only send truly transactional emails to unsubscribed users.
Sending Limits & Billing
No monthly sending cap. You can send as many transactional emails as needed
Billing is usage-based: You're billed after emails are sent, not upfront
Usage tracking: Monitor your usage in Analytics to estimate your monthly bill
Separate from marketing limits: Transactional email sends do not count against your regular campaign sending limits
What Happens If You Disable the Add-On
If you toggle the Transactional Email add-on OFF:
Your API credentials remain active
However, email sending will stop immediately
Any API requests will fail
You will not be billed for that period
Re-enabling the add-on restores sending functionality using the same API credentials.
Common Questions & Troubleshooting
Q: Why are my API requests failing?
Check these common issues:
Domain not verified: Go to Settings → Domains and ensure your sending domain is verified
Invalid API key: Double-check you copied the entire API key correctly
Invalid recipient: Ensure the recipient email address is properly formatted
Add-on disabled: Verify the Transactional Email add-on is toggled ON
View detailed error messages in Analytics → Logs.
Q: How do I estimate my monthly bill?
Use this formula:
Base fee: $10 (includes 3,000 emails)
Overage: (Total emails sent - 3,000) × $0.003
Example: If you send 10,000 emails in a month:
Base: $10
Overage: (10,000 - 3,000) × $0.003 = $21
Total: $31
Monitor your sending volume in Analytics to track usage throughout the month.
Q: Can I use this for email verification during signup?
Yes! Account registration confirmations, email verification links, and welcome emails triggered by signup are perfect use cases for transactional emails.
Q: What if I need help with the API integration?
Contact SendX support with:
Your API request details (remove sensitive data like API keys)
Error messages from the Logs section
What you're trying to accomplish
Our team can help troubleshoot integration issues.