What are ListKit's pre-warmed inboxes and how do I set them up?

THIS ARTICLE IS FOR: All ListKit customers
​Stage: Onboarding
​Owner: CS
​Last updated: Aug 2026
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When you set up cold email infrastructure the traditional way, you register new domains, configure DNS records, and then wait 2 to 3 weeks for your inboxes to warm up before you can send a single campaign. Then you wait another week for the ramp-up period. That is up to 4 weeks before your first email goes out.
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ListKit's pre-warmed inboxes eliminate that wait entirely.
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These are domains and inboxes that ListKit has already registered, configured, and warmed up in advance, pulled from a managed pool of ready-to-send infrastructure. When you claim them during your bundle setup, they are attached to your account and ready to send from in minutes.
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This is the recommended option for all new bundle setups and for anyone who wants to start sending as quickly as possible.
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Step 1: Go to your Billing page

Click your initials at the bottom left of your ListKit dashboard and select Billing from the menu.
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Step 2: Click Setup Now

Scroll down to the Bundle Setup section and click Setup Now next to your bundle.
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Step 3: Click Confirm and Pick Domains

A setup confirmation screen will appear showing what is included, 20 domains, 40 inboxes, all at no extra charge. Click Confirm and Pick Domains to continue.
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Step 4: Select Use pre-warmed domains and inboxes

On the domains page you will see two options:
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Use pre-warmed domains and inboxes (Recommended)
Claim domains from ListKit's pool that have already been registered and warmed up. Both the domains and their inboxes are ready to send from immediately. Send your first email in 5 to 10 minutes.
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Generate new domains
Register brand new domains for your keyword. These still require the standard warmup period before sending. Send your first email in 2 to 3 weeks.
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Select Use pre-warmed domains and inboxes and click Continue.
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Step 5: Select your pre-warmed domains

A list of available pre-warmed domains will load, each showing Available and Warmed status. Click Auto-select to let ListKit pick your 20 domains automatically, or browse and select them manually.
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Step 6: Add your website redirect URL

Enter your main company website. This is where prospects will be redirected if they visit one of your sending domains directly.
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Click Continue to Personas.
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Step 7: Set up your sender personas

Add two sender personas, a first name, last name, and inbox username for each. These are the names that will appear in the From field of your emails.
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For each persona, click Assign Domains and select all available domains. Click Save Assignment.
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Once both personas have all domains assigned, click Continue to Checkout.
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Step 8: Confirm your setup

Review your order summary and click Confirm. ListKit will begin attaching your 20 pre-warmed domains and 40 inboxes to your account.
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Step 9: Your pre-warmed domains are claimed

A confirmation screen will appear showing all 20 domains attached to your account. Click Go to my Inboxes. Your inboxes will appear in the Inboxes tab inside Email Engine within a few minutes and are ready to use immediately.

ListKit analyzed every campaign run through its platform and compared two groups:
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ListKit's pre-warmed inboxes: domains and inboxes provisioned, warmed, and managed by ListKit.
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Self-configured branded domain inboxes: inboxes that customers set up themselves on their own domains and connected independently.
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Across over 1.7 million classified sends, the difference is decisive:

2.5x higher reply rate
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ListKit's pre-warmed inboxes achieved a 0.848% reply rate vs. 0.336% on self-configured branded domain inboxes.
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3.6x more positive replies per 10,000 emails sent
4.7 genuinely interested replies per 10,000 sent on ListKit's pre-warmed inboxes vs. 1.3 on self-configured branded domain inboxes, the number that turns into booked meetings and pipeline.
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88% of clients who tried both saw better results with ListKit's pre-warmed inboxes
In a head-to-head test across 68 clients running the same offer to the same audience, ListKit's pre-warmed inboxes delivered a higher reply rate for 60 of them.
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The math is simple, more positive replies means more meetings booked, more pipeline, and more closed deals. Everything else in a cold email campaign stays the same. The inbox is the only variable that changes.
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ListKit's pre-warmed inboxes run a higher bounce rate of 4.43% compared to 0.61% on self-configured branded domain inboxes. This is real, expected, and worth understanding.
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Pre-warmed inboxes are freshly provisioned infrastructure. Self-configured branded domain inboxes are typically on established domains with years of sending history, which naturally produces a lower bounce rate. Two things keep this firmly in the safe zone:
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It stays under the danger line.
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The cold email industry threshold for a problematic bounce rate is 5%. At 4.43%, ListKit's pre-warmed inboxes stay comfortably under that line. Warmup and inbox rotation are built specifically to keep it there.
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Your primary domain is never touched.
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All sending volume runs on separate infrastructure, not your main business domain. Your company email and website domain are never at risk from cold email sending activity.
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The higher bounce rate is a known and managed characteristic of fresh infrastructure, not a sign of a problem.
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If you are new to cold email, pre-warmed inboxes remove the single biggest barrier to getting started. the wait. No warmup period, no ramp-up, no technical configuration. You claim your domains, set up your personas, and you are ready to send within minutes of completing setup.
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If you have done cold email before and are used to running inboxes on your own branded domains, the data across 88% of clients who have tried both is clear. ListKit's pre-warmed inboxes produce more replies, more positive replies, and more pipeline. Not slightly more. Meaningfully more.
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After completing setup with pre-warmed inboxes, your domains are attached, your inboxes are active, and you can launch your first campaign within minutes. No waiting. No warmup. Just results from day one.
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