# Email Deliverability & Authentication

Proper email authentication is essential for ensuring your emails reach the inbox. This guide explains how Engage Studio helps you authenticate your emails and maintain a strong sender reputation.

## Why Authentication Matters

Email authentication helps mailbox providers (Gmail, Outlook, Yahoo) recognize you as a legitimate sender and deliver your emails to the inbox instead of spam. Engage Studio automates most of the authentication process, but understanding the basics helps you maintain high deliverability.

## Authentication Protocols

### SPF (Sender Policy Framework)

SPF verifies that emails are sent from authorized mail servers for your domain.

**What it does:**

* Lists which servers can send email on behalf of your domain
* Helps prevent spammers from forging your domain


**How Engage Studio handles it:**

* Automatically generates the SPF record when you configure your domain
* You add the provided TXT record to your DNS settings
* No ongoing maintenance required


Best Practice
Use a subdomain like `mail.yourdomain.com` for marketing emails to keep authentication separate from your corporate email.

### DKIM (DomainKeys Identified Mail)

DKIM adds a digital signature to your emails to verify they haven't been altered in transit.

**What it does:**

* Signs each email with a cryptographic signature
* Receiving servers verify the signature using your public key


**How Engage Studio handles it:**

* Generates encryption keys automatically
* Signs every outgoing email
* Provides the DNS record to publish your public key


Best Practice
Verify your DKIM records are active before sending production emails.

### DMARC (Domain-based Message Authentication, Reporting & Conformance)

DMARC tells receiving servers what to do when SPF or DKIM checks fail.

**What it does:**

* Sets a policy for handling failed authentication
* Provides reports on your email authentication performance


**DMARC Policies:**

| Policy | What happens | When to use |
|  --- | --- | --- |
| `p=none` | No action - emails deliver normally, but you get reports | **Start here** - Monitor without affecting delivery |
| `p=quarantine` | Suspicious emails go to spam folder | After achieving >95% authentication pass rate |
| `p=reject` | Failed emails are blocked completely | After long-term monitoring confirms stability |


**How Engage Studio handles it:**

* Provides a recommended DMARC record during domain setup
* You can configure reporting emails to monitor authentication


Important
If your main domain already has a DMARC record, you may not need to configure the one provided by Engage Studio. Check with your IT team.

## IP Warming & Reputation

### Understanding IP Warming

IP warming is the process of gradually building a positive sending reputation with mailbox providers.

**Why it matters:**

* New IP addresses have no reputation with mailbox providers
* Sending large volumes immediately from a new IP looks suspicious
* Reputation is earned over time through consistent, high-quality sending


### How Engage Studio Manages IPs

Engage Studio uses **Amazon SES managed IP pools**, which automatically handle IP allocation based on your sending volume:

* **Starting out (low volume):** Your emails are sent from shared IPs that already have established reputation. No warming needed.
* **Growing (medium volume):** As your volume increases, Amazon SES may transition you to dedicated IPs and automatically warms them.
* **Established (high volume):** High-volume senders (typically 100,000+ emails/day) get dedicated IPs with isolated reputation.


**The key benefit:** You don't need to manually warm IPs. Amazon SES handles the entire process automatically.

## Best Practices for Deliverability

### Build Your Reputation

Even with automated IP management, follow these practices:

**1. Start with engaged subscribers**

* Send first to people who recently opened or clicked your emails
* Avoid sending to old, inactive lists right away


**2. Increase volume gradually**

* Don't jump from 1,000 to 100,000 emails overnight
* Increase volume steadily over days and weeks
* Watch for sudden drops in engagement or increases in bounces


**3. Maintain consistency**

* Send regularly (daily or weekly) rather than sporadic bursts
* Keep sender names and addresses consistent
* Avoid sudden changes in content style or format


### Keep Your List Clean

**Remove bad addresses:**

* Hard bounces (invalid addresses)
* Spam complaints
* Addresses that never engage


**Validate new subscribers:**

* Use double opt-in to confirm email addresses
* Validate email format before adding to your list


### Monitor Key Metrics

Track these metrics to maintain good deliverability:

| Metric | Target | Why it matters |
|  --- | --- | --- |
| Bounce rate | <2% | Too many bounces signals poor list quality |
| Complaint rate | <0.1% | High complaints damage sender reputation |
| Open rate | Industry average | Sudden drops indicate deliverability issues |
| Engagement | Steady or growing | Shows recipients value your emails |


### Create Quality Content

**Avoid spam triggers:**

* Excessive use of words like "FREE", "LIMITED TIME", "ACT NOW"
* ALL CAPS subject lines
* Too many exclamation points!!!


**Balance your email:**

* Mix text and images (don't send image-only emails)
* Include a clear unsubscribe link
* Make emails mobile-friendly


**Stay compliant:**

* Include your physical mailing address
* Honor unsubscribe requests promptly (within 24-48 hours)
* Only email people who gave permission


## Troubleshooting

### Emails Going to Spam

**Check these first:**

1. Verify SPF, DKIM, and DMARC are passing (check email headers)
2. Review content for spam trigger words
3. Confirm you're sending to engaged subscribers
4. Check your sender reputation using [Google Postmaster Tools](https://postmaster.google.com)


### High Bounce Rates

**If you're seeing >5% bounces:**

1. Remove invalid email addresses immediately
2. Implement email validation at signup
3. Verify DNS records are configured correctly
4. Never use purchased or scraped email lists


### Low Engagement

**If open/click rates are dropping:**

1. Improve subject lines and preview text
2. Test different send times
3. Segment your list by behavior and interests
4. Re-engage inactive subscribers with a win-back campaign
5. Remove subscribers who haven't engaged in 6+ months


## Monitoring Tools

### Built into Engage Studio

* [Email Delivery Events](/products/marketing-cloud/engage-studio/channels/email/email-delivery-events-table) - Track sent, delivered, bounced, and complained events
* [Email Error Events](/products/marketing-cloud/engage-studio/channels/email/email-error-events-table) - Diagnose specific delivery failures
* Domain verification status - Monitor SPF/DKIM/DMARC in Sending Configurations


### External Tools

* **Google Postmaster Tools** - Monitor domain reputation, spam rate, delivery errors for Gmail
* **Microsoft SNDS** - Check your IP reputation for Outlook/Hotmail
* **DMARC Analyzers** (dmarcian, Postmark) - Parse DMARC reports to identify authentication issues


## Next Steps

1. **Set up authentication:** Follow the [Domain Configuration](/products/marketing-cloud/engage-studio/channels/email/email-domain-configuration) guide to configure SPF, DKIM, and DMARC
2. **Configure sender profiles:** Create sender profiles with proper unsubscribe headers ([Sender Configuration](/products/marketing-cloud/engage-studio/channels/email/email-sender-configuration))
3. **Start sending:** Begin with engaged subscribers and gradually increase volume
4. **Monitor performance:** Watch delivery metrics and adjust your strategy as needed