Custom Domains

What this feature is for

Custom domains let you send and receive email using your own domain instead of inboxlayer.dev. Once verified, inboxes can operate as inbox_name@yourdomain.com across the API, SMTP, and IMAP.

Workflow

1. Create custom domain via API or web UI.
2. Configure DNS records on your domain.
3. Trigger verification.
4. Monitor verification status before routing production traffic.
5. Delete or update when domain lifecycle changes.

DNS records required

After creating a custom domain, configure these records with your DNS provider:

MX record (required for inbound)

Type:     MX
Name:     yourdomain.com
Value:    smtp.inboxlayer.dev
Priority: 10

DKIM records (required for outbound signing)

Three CNAME records are provided when you create the domain. All three must be configured:

Type:  CNAME
Name:  token1._domainkey.yourdomain.com
Value: token1.dkim.amazonses.com

Type:  CNAME
Name:  token2._domainkey.yourdomain.com
Value: token2.dkim.amazonses.com

Type:  CNAME
Name:  token3._domainkey.yourdomain.com
Value: token3.dkim.amazonses.com

The exact token values are returned by the API when you create the domain.

SPF record (recommended)

Type:  TXT
Name:  yourdomain.com
Value: v=spf1 include:amazonses.com ~all

DMARC record (recommended)

Type:  TXT
Name:  _dmarc.yourdomain.com
Value: v=DMARC1; p=none;

SMTP and IMAP with custom domains

Once verified, use your custom domain email address as the username for both SMTP and IMAP:

• Username: inbox_name@yourdomain.com
• Password: Your API token (unchanged)

Outbound messages will use your custom domain as the From address automatically. If the domain is pending or failed verification, the system falls back to inbox_name@inboxlayer.dev.

Endpoints

• GET /api/v1/custom_domains
• POST /api/v1/custom_domains
• GET /api/v1/custom_domains/{id}
• PATCH /api/v1/custom_domains/{id}
• DELETE /api/v1/custom_domains/{id}
• POST /api/v1/custom_domains/{id}/verify

Notes for agents

• Poll GET /api/v1/custom_domains/{id} after triggering verification. DNS propagation may take minutes.
• Do not route production traffic until verified_status is verified.
• All three DKIM records must resolve before verification succeeds.