What is transactional email?
Transactional email is an automated message sent to a single recipient in response to a specific action, such as a password reset, order confirmation, or account verification. Unlike marketing email sent in bulk, transactional email is triggered by user behavior and typically achieves open rates above 80%.
Common examples include password reset links, order receipts, shipping notifications, account verification emails, two-factor authentication codes, and invoice delivery. These emails are expected by the recipient and are critical to your application's user experience.
Send via API or SMTP
RelayPost supports two methods for sending transactional email. Choose the one that fits your stack.
REST API
Send email with a single HTTP request. Best for modern applications, serverless functions, and high-volume sends.
curl -X POST https://api.relaypost.dev/v1/emails/send \
-H "Authorization: Bearer YOUR_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"from": "[email protected]",
"to": "[email protected]",
"subject": "Reset your password",
"html": "<p>Click <a href=\"...\">here</a> to reset.</p>"
}'SMTP Relay
Point your existing SMTP config at RelayPost. No code changes needed for WordPress, Rails, Django, or any app that sends email via SMTP.
Host: smtp.relaypost.dev
Port: 587 (STARTTLS) or 465 (TLS)
Username: your-smtp-username
Password: your-smtp-passwordTransactional vs marketing email
| Aspect | Transactional email | Marketing email |
|---|---|---|
| Trigger | User action (purchase, signup, password reset) | Business decision (campaign, newsletter) |
| Recipients | Single individual | List or segment |
| Content | Expected, action-specific | Promotional, informational |
| Open rate | 80–90% | 15–25% |
| Unsubscribe link | Not required | Required by law (CAN-SPAM) |
| Examples | Password reset, order receipt, 2FA code | Newsletter, product launch, sale |
| Sending method | API trigger from app code | Campaign builder or scheduler |
RelayPost handles both transactional and campaign email in a single platform — no need for separate providers.
Common transactional email examples
🔑 Password reset
Time-sensitive link sent when a user requests a password change. Must arrive within seconds.
🧾 Order confirmation
Receipt with order details, total, and tracking information sent immediately after purchase.
✅ Email verification
Confirmation link sent during signup to verify the user owns the email address.
🔐 Two-factor authentication
One-time code sent as a second authentication factor. Delivery speed is critical.
📦 Shipping notification
Tracking updates sent when an order ships, is out for delivery, or has been delivered.
💳 Invoice & billing
Payment receipts, upcoming renewal reminders, and failed payment notifications.
Why developers choose RelayPost
Fast delivery
Transactional emails are delivered in under 3 seconds. Password resets and 2FA codes arrive when users expect them.
Automatic authentication
SPF, DKIM, and DMARC are configured automatically when you verify your domain. No manual DNS debugging.
Real-time webhooks
Get instant notifications for delivery, bounce, open, and complaint events via HTTP webhooks.
Suppression management
Automatic suppression of bounced and complained addresses protects your sender reputation.
Pricing
Free
$0/month
1,000 emails/month
API + SMTP access
Starter
$5/month
10,000 emails/month
Priority support
Pro
$25/month
100,000 emails/month
Dedicated IP available
No per-email overage charges. Full pricing details →
Frequently asked questions
What is transactional email?
Transactional email is an automated message sent to a single recipient in response to a specific action, such as a password reset, order confirmation, or account verification. Unlike marketing email sent in bulk, transactional email is triggered by user behavior and typically achieves open rates above 80%.
What is the difference between transactional and marketing email?
Transactional emails are triggered by user actions (password reset, order receipt) and sent to one person. Marketing emails are sent in bulk to a list for promotional purposes. Transactional emails don't require an unsubscribe link and have much higher open rates (80%+ vs 15-25%).
How much does transactional email cost?
RelayPost offers 1,000 transactional emails per month free. Paid plans start at $5/month for 10,000 emails and $25/month for 100,000 emails. There are no per-email overage charges or hidden fees.
Can I send transactional email via SMTP?
Yes. RelayPost supports both REST API and SMTP relay for sending transactional email. SMTP is ideal for legacy applications, CMS plugins, and frameworks like WordPress or Rails. The API is better for modern applications that need templates, scheduling, and detailed tracking.
Do transactional emails need an unsubscribe link?
No. Transactional emails triggered by user actions (password resets, receipts, verification codes) are exempt from CAN-SPAM unsubscribe requirements. However, if your transactional email includes promotional content, an unsubscribe link is recommended.
Start sending transactional email
Free tier includes 1,000 emails per month. No credit card required.
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