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Domains are the foundation of your email infrastructure in Lettr. When you send emails through Lettr, email providers like Gmail and Outlook verify that you’re authorized to send on behalf of your domain. Without proper domain configuration, your emails may be rejected or filtered to spam folders. Lettr uses DNS records to establish this authorization. By adding specific records to your domain’s DNS settings, you prove ownership and grant Lettr permission to send, track, and receive emails on your behalf. This process, called domain verification, enables email authentication protocols like SPF, DKIM, and DMARC that are now required by major email providers. Depending on your needs, you can configure different domain types for different purposes. Most users start with a sending domain to authenticate outbound emails, then add tracking and storage domains to maintain brand consistency across all email components.

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Domain Types

Lettr supports four types of domains, each serving a specific purpose:
Domain TypePurposeKey Features
Sending DomainSend emails from your domainSPF, DKIM, DMARC authentication
Tracking DomainCustom tracking links and pixelsHTTPS with auto-provisioned SSL
Inbound DomainReceive emails at your domainMX record configuration
Storage DomainHost email assets and contentCustom CDN for images and files

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Why Verify Domains?

Domain verification establishes your identity as a legitimate sender:
  • Inbox placement — Properly authenticated emails pass SPF and DKIM checks, which is the primary signal email providers use to decide whether to deliver your message to the inbox or filter it to spam
  • Brand recognition — Send from your own domain rather than a shared one, reinforcing your brand with every email
  • Compliance — Major email providers — including Google and Yahoo — now require SPF, DKIM, and DMARC authentication for bulk senders
  • Spoofing protection — Domain authentication lets receiving servers reject forged messages that claim to come from your domain

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Quick Start

1

Add Domain in Dashboard

Go to Domains → Sending → Add Domain and enter your domain name.
2

Add DNS Records

Add the provided SPF, DKIM, and DMARC records to your DNS provider.
3

Verify Domain

Click Verify to confirm DNS propagation. This may take a few minutes.

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Add Domain via API

Register a new sending domain with POST /domains. The request body contains only the domain name: Create a sending domain: 
curl -X POST https://app.lettr.com/api/domains \
  -H "Authorization: Bearer lttr_xxxxxxxxxxxx" \
  -H "Content-Type: application/json" \
  -d '{
    "domain": "example.com"
  }'
Response: 
{
  "message": "Domain created successfully.",
  "data": {
    "domain": "example.com",
    "status": "pending",
    "status_label": "Pending Review",
    "dkim": {
      "public": "MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQ...",
      "selector": "scph0722",
      "headers": "from:to:subject:date"
    }
  }
}

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Required DNS Records

For a basic sending domain setup, you’ll need these DNS records:
TypeNameValuePurpose
TXT{selector}._domainkeyv=DKIM1; k=rsa; h=sha256; p=...DKIM signing
TXT_dmarcv=DMARC1; p=none; rua=mailto:dmarc@example.comDMARC policy
CNAME@ (root domain)sparkpostmail.comDomain verification
The DKIM selector and public key are unique to your domain and will be provided when you add your domain. Copy them exactly as shown.

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Domain Status

Each domain has an approval status that determines whether you can send emails:
StatusDescription
pendingDomain awaiting review
approvedDomain approved for sending
blockedDomain blocked from sending
DNS records are verified separately with their own status values (valid, unverified, invalid, missing, not_applicable). Check domain status via API: 
curl https://app.lettr.com/api/domains/example.com \
  -H "Authorization: Bearer lttr_xxxxxxxxxxxx"

{
  "message": "Domain retrieved successfully.",
  "data": {
    "domain": "example.com",
    "status": "approved",
    "status_label": "Approved",
    "can_send": true,
    "cname_status": "valid",
    "dkim_status": "valid",
    "dmarc_status": "valid",
    "spf_status": "valid",
    "is_primary_domain": true,
    "tracking_domain": "links.example.com",
    "dns_provider": "cloudflare",
    "created_at": "2024-01-15T10:30:00Z",
    "updated_at": "2024-01-15T10:35:00Z"
  }
}

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Domain Approval

When you add a new sending domain, Lettr automatically evaluates it through a scoring system. Each domain starts at 100 points, with deductions for risk factors like very new registration, uncommon TLDs, or suspicious naming patterns. Domains scoring 50 or above are approved automatically. The scoring evaluates:
  • Domain age — Older, established domains score higher (2+ years is ideal)
  • Domain characteristics — Standard TLDs and conventional naming patterns
  • Active website — AI-powered analysis of website legitimacy and content quality
Domains meeting the approval threshold are approved within minutes. If your domain is blocked, you can request a manual review by contacting support@lettr.com. For full details on scoring criteria, thresholds, and tips for improving your score, see Domain Approval Process.

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Learn More

Sending Domains

Configure domains for sending emails with SPF, DKIM, and DMARC

Tracking Domains

Set up custom domains for click and open tracking

Inbound Domains

Receive emails at your domain

Storage Domains

Host email assets on your own domain

DMARC

Protect your domain with DMARC policies

BIMI

Display your logo in email clients

Domain Approval

How domain scoring and approval works

Domain Connect

Automatic DNS setup for Cloudflare domains