The Smartlead playbook

Smartlead runs the campaigns. Your domain still has to earn the inbox.

Smartlead sends through the Google, Outlook or SMTP mailboxes you connect, and warms each one inside a pool that includes other warm-up users’ mailboxes. The domain behind them carries a reputation of its own. Keep every campaign where it is. Add the domain here and we build its reputation while Smartlead keeps sending.

Start warming my domainSee Inbox Boost
The Smartlead playbook

Keep sending from Smartlead. Warm the domain here.

Step 1

Connect and authenticate your mailboxes

Smartlead connects Google mailboxes by OAuth, which it recommends over app passwords, plus Outlook mailboxes and SMTP accounts from nearly any other provider. Authentication belongs to the mailbox provider, and Smartlead lists missing or misaligned SPF, DKIM or DMARC as a cause of disconnections and deliverability problems.

Step 2

Know what Smartlead’s warm-up does

Turning on warm-up puts a mailbox in a pool with other warm-up users’ mailboxes, where warm-up emails are sent, opened, saved from spam and replied to. It works mailbox by mailbox, and Smartlead’s bounce protection takes accounts out of the pool to protect their reputation.

Step 3

Add your sending domain to Inbox Boost

Add the domain your mailboxes send as, the one in your From address, such as outreach.yourbrand.com, and we build its sender reputation for you, alongside whatever warm-up you run in Smartlead. Nothing to connect: no API key, no app, no mailbox sign-in, no change to your Smartlead account.

Step 4

Keep every campaign running in Smartlead

Campaigns, sequences and sending limits all stay in Smartlead. Mailbox providers score the domain in your From address, so the reputation built here counts for every mailbox sending as outreach.yourbrand.com.

Step 5

Check where Smartlead mail lands

Inbox placement tests show whether your campaign emails reach Primary, Promotions or Spam across the major mailbox providers, and blacklist monitoring keeps watching the domain once it is warm.

  • Nothing to connect: no Smartlead API key, app, integration or mailbox sign-in
  • Nothing to change: campaigns, mailboxes and warm-up settings stay exactly as they are
  • OAuth or SMTP: it works either way, because the reputation belongs to the domain
  • Watched after warmup: blacklist and authentication monitoring on your sending domain
Features Smartlead senders lean on

The parts of the platform this plan leans on.

Feature

Inbox Boost

Add a domain. We provision the sending server and publish your DNS.

Learn more Feature

Inbox placement testing

See whether you land in Primary, Promotions or Spam across providers.

Learn more Feature

Blacklist monitoring

45+ blacklist & reputation sources, scored 0-100 with trend history.

Learn more
See it play out

A Smartlead domain, warmed without pausing a single send.

Four checkpoints, in order. Click any step or let it play.

smartlead · outreach.yourbrand.com
Google OAuthconnected
SPF, DKIM, DMARCaligned
domain historynone yet
Questions

Smartlead questions, answered.

Does Inbox Boost connect to my Smartlead account or mailboxes?
No. There is no API key, app or integration to install, and nothing signs in to your Google or Outlook mailboxes. Inbox Boost works on the sending domain, and Smartlead keeps sending your campaigns exactly as it does now.
Smartlead already warms my mailboxes. Why warm the domain too?
Smartlead’s warm-up works mailbox by mailbox inside its pool. Mailbox providers also score the domain those mailboxes share, and Inbox Boost works on that domain itself, alongside Smartlead’s warm-up. Your warm-up settings can stay as they are.
Does Inbox Boost need access to my Google Workspace mailboxes?
No. Inbox Boost does not sign in to any mailbox or ask for Gmail permissions. Google’s policy says apps using the Gmail API must not use multiple accounts to bypass Gmail account limits or circumvent spam filters; Inbox Boost stays out of your mailboxes entirely and works on the sending domain.
Should I set a custom tracking domain in Smartlead?
Smartlead recommends it. Its default tracking URLs are shared with other customers, and Smartlead says they can negatively impact deliverability. A custom tracking domain is a CNAME on your own domain, verified in Smartlead, and it does not change anything on the Inbox Boost side.
Can I see whether it is working?
Yes. Inbox placement tests show where your Smartlead campaign emails land, Primary, Promotions or Spam, across the major mailbox providers, and blacklist monitoring keeps watching the domain afterwards.
About the Smartlead facts on this page

Checked against Smartlead's own documentation on 12 October 2026. Smartlead is a trademark of its owner; SenderSignal is not affiliated with it.

Other cold outreach: Instantly, Lemlist, Apollo, Woodpecker, Reply.io. All use cases.

Smartlead keeps sending

Warm the domain behind your Smartlead campaigns.

Start free, add the domain, and keep every campaign running in Smartlead while its reputation builds.

Start freeHow Inbox Boost works