Smartlead Dedicated Domains and Mailbox Setup

Smartlead dedicated domains are outbound domains you control, separate from your primary company domain, with Google Workspace mailboxes that connect into Smartlead for campaigns and replies. Smartlead schedules the send. The domains and seats decide what receiving inboxes trust. A sequencer subscription on its own does not give you authenticated outbound domains. This guide is the purchase and setup path for that domain layer.

For what Smartlead still needs underneath, see the Smartlead Infrastructure Layer guide. For related guides, see Mailboxes for Smartlead and Smartlead Dedicated Domains and Mailbox Setup.

1. Dedicated outbound domains (not the primary brand domain).
2. Official Google Workspace seats on those domains.
3. MX, SPF, DKIM, and DMARC passing before campaigns.
4. Sane density and daily caps.
5. Mailboxes connected in Smartlead using documented methods.
6. Optional warmup, then ramp.

Skip any of those and the account can still show as connected in Smartlead. Placement depends on the rest of this setup.

Register or assign outbound domains close to the brand and redirect them to the main site. Never put cold volume on the apex domain that carries invoices, hiring, and customer mail. See Primary Domain Isolation for Cold Email at /blog/primary-domain-isolation-cold-email.

Agencies: one client, one pool. Prefer separate organizations when the plan supports it. See Cold Email Inboxes for Agencies: Isolation First.

Standard paid Workspace users in an organization you admin give you real inboxes and an Admin console for 2FA, resets, and offboarding. Unnamed SMTP inboxes may connect to Smartlead and still share reputation with other senders; Google's sender guidelines note that the activity of any sender on a shared IP address affects the reputation of all senders on it. See Dedicated Google Workspace vs Shared Cold Email Infra at /blog/dedicated-google-workspace-vs-shared-cold-email-infra and Buy Mailboxes for Cold Email Without Shared SMTP Risk at /blog/buy-mailboxes-without-shared-smtp.

Finish MX, SPF, DKIM, and DMARC before warmup starts and before campaign volume. Google's sender guidelines ask all senders to Gmail to set up SPF or DKIM and keep the spam rate reported in Postmaster Tools below 0.3%; senders of more than 5,000 messages a day to Gmail also need SPF, DKIM, and DMARC. Cold outbound should meet the fuller set anyway. Verify with Show original. Overview at /blog/authentication-cold-email-google-workspace. Steps at /blog/spf-dkim-dmarc-cold-email-setup.

Common operator practice is two or three mailboxes per domain, soft ceiling around five, and roughly 20 to 40 cold sends per warmed mailbox per day including follow ups. Capacity comes from more domains, not from packing one domain for Smartlead to rotate harder. See Mailbox Density Per Domain for Outbound at /blog/mailbox-density-per-domain-outbound and How Many Mailboxes Per Domain for Cold Email at /blog/how-many-mailboxes-per-domain-cold-email.

Smartlead's help center documents signing in with Google (OAuth), connecting Gmail with IMAP and SMTP using an app password, and bulk adding accounts for larger batches. A Workspace admin may need to allow Smartlead's app before OAuth works, and app passwords require 2 Step Verification. Check Smartlead's help center for the current steps. Name mailboxes so domain ownership is obvious in the Smartlead UI. Instantly users follow a parallel path; ColdMail mailboxes are ready to connect in Instantly and Smartlead using the methods those tools support.

Warm new seats before full caps. Do not treat warmup as a placement guarantee. See Warmup Myths That Waste Cold Email Teams at /blog/warmup-myths-cold-email and Warmup Myths That Waste Cold Email Teams at /blog/warmup-myths-cold-email. Rotate across domains, not only across seats. See Mailbox Rotation for Cold Email Infrastructure at /blog/mailbox-rotation-cold-email.

Smartlead documents how to set up a custom tracking domain with a CNAME record. Take the record values from Smartlead's help center, not from a blog post. A tracking CNAME is not MX and not SPF. If placement is fragile, revisit open tracking tradeoffs. See Tracking Pixels and Cold Email Placement Tradeoffs at /blog/tracking-pixels-cold-email-placement.

Before purchasing, confirm:

• Domains transferable to an account you control.
• Platform named as official Google Workspace.
• Admin access with 2FA.
• DNS visible (automated is fine; opaque is not).
• Clear path into Smartlead with documented connect methods.
• Warmup optional and adjustable.
• No guaranteed or fixed placement rate; ask how any placement figure is measured.

Common mistakes to avoid:

• Primary domain added as a sender just for this client.
• Ten mailboxes on one new domain after a volume push.
• Connecting before DKIM is started in Admin.
• Buying a new domain batch without changing list or density. See Burned Domains: When a New Batch Does Not Help at /blog/burned-domains-new-batch-mistake.
• Judging readiness by open rate alone. See Tracking Pixels and Cold Email Placement Tradeoffs at /blog/tracking-pixels-cold-email-placement.

Work backward from daily cold volume.

1. Choose a per mailbox cap in the operator practice range (often roughly 20 to 40 once warmed).
2. Divide daily target by that cap for mailbox count.
3. Divide mailboxes by two or three for domain count.
4. Add spare domains still in warmup.

Example: 150 sends a day at 25 per mailbox needs about six mailboxes, so two or three domains. That is a planning sketch, not a rule. Google's published per user sending limit is a ceiling, not a cold email target. See Google Workspace Sending Limits for Cold Email at /blog/google-workspace-sending-limits.

On handoff day:

1. Confirm Show original passes on each domain.
2. Enforce 2FA on every seat.
3. Connect in Smartlead with documented methods only.
4. Set per mailbox daily limits before enabling campaigns.
5. Start with the cleanest list segment.
6. Watch human replies and bounces for a week before expanding.

If connection succeeds but auth fails, disconnect and fix DNS before you just send.

This setup may not be enough if:

• Your copy and offer already fail on healthy domains.
• You need Microsoft 365 in the same mailbox product (ColdMail will not cover that).
• Leadership wants a guaranteed placement percentage in the contract (decline; buy control instead).

Infrastructure removes avoidable trust failures. It does not invent product market fit.

ColdMail provisions official Google Workspace mailboxes on dedicated domains you bring or buy through ColdMail, publishes SPF, DKIM, DMARC, and MX automatically, and gives you an admin panel per domain with 2FA plus provider health indicators. AI warmup is available as an optional add on; see coldmail.app for current add on pricing. Multiple organizations are available on supporting plans. No shared SMTP pool. No Microsoft 365 mix.

ColdMail is not a sequencer. Mailboxes are ready to connect in Instantly and Smartlead using the methods those tools support, and they work with n8n and other tools.

Set up your mailboxes on dedicated domains at coldmail.app, or Book a Strategy Call to size the pool under Smartlead.