When sending emails through the platform, you can choose between two methods: SMTP or a Connected Domain. Both let you send under your own domain, but they work very differently behind the scenes and are suited to different needs. This article explains how each method works, when to use one over the other, and the important DNS impact you need to understand before setting up a Connected Domain.
What Is SMTP Sending?
SMTP sending works by granting Value Builder System permission to send emails on your behalf using your own email account's SMTP credentials, such as your Gmail, Outlook/Office 365, or company mail server. Because emails are sent through your own mailbox, they genuinely come from your own domain, and you keep full visibility into what's sent, since messages typically show up in your own Sent folder just like any email you send yourself. No DNS changes are required, since you're using an account that's already authenticated and trusted.
What Is a Connected Domain?
A Connected Domain routes your outgoing emails through Value Builder's own sending infrastructure, powered by Mailgun, instead of your personal mailbox. To make those Mailgun-sent emails appear as if they come from your domain, you need to add authentication records to your domain's DNS. This approach is generally used for higher-volume sending, since Mailgun is built to handle bulk sending beyond what a typical mailbox allows. The tradeoff is that because emails route through Mailgun rather than your own account, you lose direct visibility, sent messages will not appear in your personal Sent folder or everyday email activity. It's also important to understand that DNS records apply at the domain level, so this change affects any system or person sending email from that domain, not just Value Builder.
Key Differences
Sending method: SMTP sends through your existing email account. A Connected Domain sends through Value Builder's Mailgun infrastructure.
Visibility: SMTP keeps full visibility, since sent emails appear in your own mailbox. A Connected Domain reduces visibility, since sending happens through Mailgun, outside your personal inbox.
Sending volume: SMTP is best for standard, everyday sending volumes. A Connected Domain is built for higher-volume sending.
DNS impact: SMTP requires no DNS changes at all. A Connected Domain requires adding DNS records that affect every mailbox and system sending email from that domain, not just Value Builder.
Setup and risk: SMTP is quick and low risk. A Connected Domain requires technical coordination and carries a risk of disrupting other email or services on the domain if misconfigured.
Best for: SMTP suits most everyday users. A Connected Domain suits organizations with high sending volume and dedicated technical support.
When to Use SMTP (Recommended for Most Users)
For most users, SMTP is the recommended option. It requires no DNS changes, sends genuinely from your own account, keeps full visibility into what's been sent, and takes only a few minutes to set up by granting permission for Value Builder to send on your behalf. Unless you have a specific need for high-volume sending, SMTP is the simpler, safer, and more transparent choice.
When to Use a Connected Domain
Consider a Connected Domain only if you regularly send high volumes of email that exceed what a standard mailbox can handle, and you have a technical resource available who can safely manage domain-wide DNS records. This option is best suited to organizations with established technical or IT support.
Important: How a Connected Domain Changes Your DNS
Connecting a domain requires adding authentication records, such as SPF, DKIM, and CNAME records, to your domain's DNS so that Mailgun is authorized to send email as your domain. Please read this section carefully before proceeding, since these changes are domain-wide.
These DNS records affect every person and system that sends email from your domain, not just Value Builder. If your organization uses other email tools, such as your everyday business email, a separate marketing platform, or another CRM, those existing DNS records must be preserved and combined correctly rather than overwritten, or you risk breaking their email delivery.
DNS changes can take anywhere from a few minutes up to 48 hours to fully propagate across the internet.
Because sending moves to Mailgun, you also lose direct visibility, sent emails will not appear in your own mailbox's Sent folder, so you'll need to rely on Value Builder's sending reports to confirm delivery.
We strongly recommend saving a copy of your current DNS records before making changes, and coordinating with your IT provider or whoever manages your domain's other email services, so nothing is accidentally overwritten or disrupted.
Bottom Line
If you're unsure which option to choose, start with SMTP. It's the fastest, lowest-risk way to send, it sends genuinely from your own account, and it keeps you fully in control and visible into your sent email. Only move to a Connected Domain if you have a genuine need for high-volume sending and the technical support in place to safely manage the domain-wide DNS changes involved.