How to Use Smartlead to Run Campaigns Across Many Inboxes

The short answer: prepare secondary sending domains, connect each mailbox, publish MX, SPF, DKIM and DMARC, point a custom tracking domain at Smartlead, enable warm-up, then create a campaign: import leads with the block and bounce filters on, write the sequence, assign warmed accounts, set the schedule and safeguards, and launch.

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Smartlead's help centre describes campaign creation in six tidy steps. The work that decides whether those emails arrive happens earlier, in the mailboxes and DNS, so this guide starts there. For what Smartlead is and what its plans include, see the Smartlead glossary entry.

What to have ready

• An account. The free trial runs 14 days with no card and allows 2,500 sends and 1,250 stored contacts, per Smartlead's trial article.
• Domains that are not your main one. Smartlead's article on secondary sending domains recommends buying domains close to your brand name, creating two or three addresses on each, and avoiding extensions such as .biz or .online and names with numbers or hyphens.
• Or bought mailboxes. SmartSenders sells ready Google mailboxes at $4.50 a mailbox a month plus $13 a domain a year, per the pricing page (checked on 23 October 2026).

Then the legal groundwork, which no setting replaces. The Dutch regulator ACM's spam guidance says commercial messages go only to recipients who gave prior consent, with an exception for existing customers about related products, that the sender must be identifiable and unsubscribing easy, and that the rules bind whoever sends, whoever commissions the sending and suppliers of address files. Other countries set different lines, so check each market on your list before you import it.

Step 1: Connect each mailbox

Open Email Accounts in the left sidebar and click + Connect Mailbox, as Smartlead's connection guide describes. Choose Smartlead's Infrastructure, or Your Email Network if you are on the Smart or Prime plan and want your own OAuth credentials. Then pick Google OAuth, Outlook or SMTP. For SMTP, try port 587 with TLS or 465 with SSL, and use an app-specific password where two-factor sign-in is on. A green Connected status means the mailbox is ready.

Step 2: Authenticate the domains

Publish MX, DKIM, SPF and DMARC records for every sending domain. Smartlead's authentication article explains each one and links setup steps for Gmail, Zoho and Outlook. Without MX records a domain cannot receive mail, and replies are the point of the exercise.

Step 3: Mask the tracking links

Open and click tracking embed links that, on a shared domain, are reused across many senders. The custom tracking article has you add a CNAME record with host emailtracking and value open.sleadtrack.com, wait between 30 minutes and 24 hours, then paste the full address into the mailbox's custom tracking field and click Verify CNAME. One aged domain can serve as the tracking domain for every mailbox in the account.

Step 4: Enable warm-up

In Email Accounts, select the mailbox, choose a configuration, click Enable Warmup and save. The warm-up article explains the settings: keep total daily warm-up emails at 10 to 20 while the account also runs a campaign, switch on daily ramp-up for a fresh domain, and set the reply rate at 20 to 30 percent. It advises against going above 30 percent unless you know exactly why.

Step 5: Create the campaign and import leads

Under Engage, open Campaigns, click + Create Campaign, name it and click Continue; the campaign opens in Draft, per the campaign guide. In the Leads tab, click + Add Leads and choose a CSV, a connected CRM, a saved list or SmartProspect.

Before importing, check the upload settings. The global block list, the unsubscribe list and the community bounce list keep blocked, opted-out and known-bouncing addresses out of the campaign. Leave all three on. Then review the automatic field mapping and import.

Step 6: Write the sequence

In the Sequence tab, click + Create First Step and choose Email, Manual Task or, if you use SmartDialer, Call, as the campaign guide sets out. For each email, write the subject and body, insert variables, and use Write with AI or AI Spintax if you want them; preview before saving. Add follow-up steps with wait times and A/B variants. A manual task pauses the sequence until someone marks it done, which suits a LinkedIn touch or a reply review.

Step 7: Assign warmed accounts

Click Next: Email Accounts and select the warmed, active mailboxes this campaign should use, following the same campaign guide. The tab shows each account's daily limit, warm-up status and other campaigns, and lets you filter by status such as Disconnected or Nearing limit. Only eligible, active accounts send.

Step 8: Configure the settings and launch

In Settings, set the timezone, start date, active days, sending window, send interval and new leads per day. Stop the campaign for a lead on reply, which the guide recommends over clicks or opens. Choose pattern-based variant distribution, again the recommended option, and know that it cannot be changed once the campaign is live.

Under Delivery Optimization you can send plain text and turn off open or click tracking. Under Protection & Limits, enable high bounce rate auto-protection, domain-level rate limiting and the unsubscribe message for every email. Then click Launch Campaign. The guide's final check asks for three things first: leads added, at least one sequence step, and email accounts assigned.

Where the help centre says setups go wrong

• A campaign that keeps pausing. The pausing article lists four causes: a missed payment, an exhausted email credit limit, every connected mailbox disconnected, or a teammate pausing it.
• Too many addresses on the main domain. The secondary domain article advises against creating 20 addresses under your primary domain to reach volume.
• Shared tracking links. The tracking article says shared URLs used across thousands of campaigns can hurt deliverability.
• A warm-up reply rate set too high. The warm-up article flags anything above 30 percent as a setting for experts only.

Still comparing tools? Smartlead vs Woodpecker sets Smartlead against a rival with a different pricing model.

FAQ

How many emails should one address send each day?

Smartlead's secondary domain article advises a maximum of 50 per address. Its worked example: 1,000 emails a day / 50 = 20 addresses, and at two or three addresses per domain that is roughly seven secondary domains.

Can I change the variant distribution after launch?

No. The campaign guide says the distribution mode cannot be changed once the campaign is live, so decide between pattern-based and randomised before you click Launch.

Should I send through Smartlead's infrastructure or my own OAuth?

Smartlead's Infrastructure is the quick route with preset settings and is open to every plan. Your Email Network sends through your own OAuth credentials and is limited to the Smart and Prime plans, according to the connection guide, which positions it for agencies and high-volume senders.