How to warm up a new domain for cold email

A new sending domain has no history. This guide gives you a week-by-week order of work for a new domain and its mailboxes. It covers DNS records, what to do while the mailboxes warm up, which signals to watch once real sending starts, and when to stop.

One point comes first and is easy to skip. Set the volume ceiling before the first email goes out, and write it into an approved policy. Warm-up tools ramp volume up. They do not decide how high is too high for your business. A person should decide that.

This guide does not give a table of daily send counts. Pick your own ceiling and record it in the policy. For background on volume and deliverability, read cold email deliverability.

Who this is for

This guide is for you if:

You are starting outbound from a domain that has never sent cold email.
You want to keep your main domain out of cold sending.
You run a small team, or one person, and need a clear order of work instead of a pile of settings.
You use Outlevo with Smartlead mailboxes you own, or with Outlevo's managed mailboxes.

It is not for you if you already have a long-running domain with a stable sending history and only need to add a mailbox. Some steps still apply, but the week-by-week plan assumes a cold start.

Steps

Step 1: Approve the policy and the ceiling

In Outlevo, nothing is sent outside a policy that a person approved. [[1]](#sources) Policies set who can be contacted, on which channels, how often and with what budget. [[1]](#sources) That makes the policy the right place for your volume ceiling. Every external action is checked against the approved policy before it runs, and recorded in a ledger. [[1]](#sources)

Why set the ceiling first? Because the pressure to send more shows up in week two or three, when the mailboxes look ready and the pipeline target is not met. A ceiling written down and approved in advance is harder to talk yourself past than one you only hold in your head.

Write down four things before you touch DNS:

Who can be contacted. The segments or lists the campaign is allowed to reach. Policies set who can be contacted. [[1]](#sources)
Which channels. Email only, or email plus LinkedIn. Policies set the channels. [[1]](#sources)
How often, and with what budget. Policies set how often and with what budget, so this is where your volume ceiling belongs. [[1]](#sources) Decide the daily and weekly volume you will allow per mailbox.
Who can change it. Name the person who approves a higher ceiling, so raising it is a decision and not a drift. A person approves the policy. [[1]](#sources)

Decide your own numbers. This guide does not supply them.

Step 2: Choose your mailbox route

You have two routes.

Managed mailboxes. Outlevo buys sending domains, creates the mailboxes through Zapmail, sets up DNS and warms them up, so you never touch your main domain. [[2]](#sources) You choose the domains Outlevo proposes and the sender names. Outlevo does the purchase, the DNS records, the mailboxes and the warm-up. [[2]](#sources) Builder includes 1 domain and 2 mailboxes. Growth includes 2 domains and 4 mailboxes. [[2]](#sources) Sending, follow-ups and the mailboxes your plan includes use no credits. [[2]](#sources) For plan prices, see pricing: Builder is USD 29 per month and Growth is USD 149 per month. [[3]](#sources)

Your own mailboxes in Smartlead. Connect your Smartlead key and Outlevo builds each campaign in Smartlead and sends from your mailboxes. [[4]](#sources) Outlevo writes and schedules the emails. Smartlead sends them from the mailboxes in your Smartlead account. [[4]](#sources) Outlevo reads each mailbox's warm-up state from Smartlead. [[4]](#sources) If you buy mailboxes yourself, Smartlead's pricing page listed them from $4.50 a mailbox a month when checked on Oct 22, 2026. [[5]](#sources) Reply.io listed domains and mailboxes as add-ons from $5 a mailbox a month on the same date. [[6]](#sources)

Either way, use a separate domain for cold sending. Keeping the main domain out of it is the whole point of the exercise. If something goes wrong, the damage stays on the domain you bought for the purpose.

Step 3: Set up the DNS records (week 0)

Before any warm-up starts, the domain needs SPF, DKIM and DMARC. With managed mailboxes, Outlevo sets up DNS for you. [[2]](#sources) With your own mailboxes, you or whoever runs your DNS publishes them.

Outlevo checks these before a Smartlead campaign sends. Every mailbox must be connected and warmed up, and its domain must have SPF, DKIM and DMARC checked in the last 7 days. [[4]](#sources) If your last check is older than that, the campaign is not ready. Plan to recheck the records any time you change mailboxes or DNS providers.

Three things are worth knowing about the records.

SPF has a lookup limit. RFC 7208 says: "SPF implementations MUST limit the total number of those terms to 10 during SPF evaluation" (checked Oct 22, 2026). [[7]](#sources) If you stack several sending services on one domain, count the terms. A new cold-sending domain should have a short, simple record for that reason.

DMARC sets a policy. RFC 7489 describes DMARC as a way for "a mail-originating organization" to "express domain-level policies and preferences for message validation, disposition, and reporting" (checked Oct 22, 2026). [[8]](#sources) Yahoo's sender guidance says: "Publish a valid DMARC policy with at least p=none" (checked Oct 22, 2026). [[9]](#sources) Start there if you are unsure, then tighten the policy once you can read the reports.

Big-sender rules exist, and the records matter before you reach them. Google says senders of more than 5,000 messages a day to Gmail accounts must set up SPF and DKIM for their domain (checked Oct 22, 2026). [[10]](#sources) Microsoft says that for domains sending over 5,000 emails a day, Outlook will soon require compliance with SPF, DKIM and DMARC (checked Oct 22, 2026). [[11]](#sources) Those lines are for high volume. Outlevo's own pre-send check asks for all three records on a Smartlead domain either way. [[4]](#sources)

Step 4: Weeks 1–3: let the mailboxes warm, send no campaigns

This stretch is quiet on purpose. A new managed mailbox sends nothing until it is warm: at least 14 days, usually about 3 weeks. [[2]](#sources) Treat 14 days as the floor and three weeks as the plan. If you run your own mailboxes in Smartlead, use the same clock for planning, and let the mailbox's warm-up state in Smartlead tell you when it is ready. Outlevo will not send a Smartlead campaign until every mailbox is connected and warmed up. [[4]](#sources)

Use this time for work that does not touch reputation:

Build the list. Decide who the campaign reaches, in line with the policy you approved in step 1.
Verify addresses. Check the list before any send. Outlevo email verification costs 1 credit per address. [[3]](#sources) See email verification for how it fits your flow. If you prefer a standalone checker, ZeroBounce's Pay as You Go started at $39 for 2,000 email validations when read on Oct 26, 2026. [[12]](#sources) More on that vendor is at ZeroBounce pricing, plans and integrations. For addresses on domains that accept everything, see the glossary entry on catch-all domains.
Write the emails. Keep them short and specific to the segment. For an example of a campaign aimed at one buyer type, see cold email to finance leaders.
Add the footer. The FTC's CAN-SPAM guide says: "Your message must include your valid physical postal address." (checked Oct 22, 2026). [[13]](#sources) Put the address in the template now, so no first-week email goes out without it.

For the concept behind this stage, see the glossary entry on mailbox warm-up.

Step 5: When the mailboxes are warm: the first sends

When the mailboxes show as warm, send the first campaign, and keep it small. How small is your call: it is the ceiling from step 1, and the first batch should sit well under it. This guide gives no daily number. Start low enough that you could read every reply and every bounce by hand.

Send to your best-verified, best-fit contacts first. A short list of well-matched people tells you more about your setup than a long list of weak matches. If you use Smartlead, Outlevo pushes campaign leads in batches of 100. [[4]](#sources) That is a transfer detail, not a recommended send size. Your daily cap still comes from the policy.

Outlevo checks each managed mailbox's warm-up state and reputation daily. [[2]](#sources) Look at that state before you decide to raise volume. Do not raise it on the same day you see a bad sign.

Step 6: After the first sends: raise volume in small steps

After the first sends, raise volume only if the signals below look healthy. Each increase is a policy change, so the person you named in step 1 approves it. Make one change at a time, so that if something breaks you know which change did it.

What to check

Reply-based signals

For Smartlead, Outlevo gets sent, reply, bounce, unsubscribe and category-change events back by webhook. [[4]](#sources) Those five event types are your dashboard. Read them in this order.

Bounces first. A bounce means an address did not accept the message. If bounces rise after you add a new batch, check the list first. Go back to verification.

Unsubscribes next. People opting out tell you the message or the targeting is off. Treat a cluster of unsubscribes from one segment as a reason to stop sending to that segment.

Replies last, and read them. Do not judge by volume alone. Read the content. A reply that says "remove me" is a different signal from a question about price.

Keep your expectations modest. Belkins' 2026 study of 7.5M B2B emails sent in 2025 found that 0.45% of emails get a reply across industries (checked Oct 22, 2026). [[14]](#sources) The study defines reply rate as replies divided by emails sent. [[15]](#sources) Smartlead reports that 0.74% of contacts reply for the median sender (checked Oct 22, 2026). [[16]](#sources) The two figures use different bases, emails in one and contacts in the other, so do not set them side by side as one range. They do show that most emails get no reply. Silence in the first days is normal and is not a reason to raise volume.

When to pause

This guide does not give a bounce-rate or reply-rate number that should trigger a pause. Set your own thresholds and write them in the policy next to the ceiling, so the rule exists before the problem does. Pick them while things are calm.

Pause rules to write down:

What bounce pattern stops a campaign.
What unsubscribe pattern stops a segment.
What mailbox state (warm-up or reputation) stops a mailbox.
Who has the authority to pause, and who must approve resuming.

Outlevo gives you the controls for it. Kill switches pause a campaign, a channel or the whole workspace at once. [[1]](#sources) Use the narrowest one that fits. If one campaign looks wrong, pause that campaign. If every mailbox shows a problem, pause the channel. Keep the whole-workspace switch for the case where you do not yet know the cause.

After a pause, find the cause before you resume. Check the DNS records again, look at which batch caused the change, and read the replies. Resume at a lower volume than before, and record the change in the policy.

Pre-send checklist

Run through this before the first campaign and again before any volume increase:

The policy is approved by a person, and the ceiling is written in it. [[1]](#sources)
The domain is separate from your main domain.
SPF, DKIM and DMARC are published, and the check is under 7 days old. [[4]](#sources)
The SPF record stays inside the 10-term limit. [[7]](#sources)
Every mailbox is warm: at least 14 days, usually about 3 weeks on managed mailboxes. [[2]](#sources)
The list is verified, and risky addresses are handled.
Every email carries your valid physical postal address. [[13]](#sources)
Pause rules are written, with a named owner.
Someone is reading replies and bounces every day during the first weeks.

Common mistakes

Sending from the main domain. One bad week then follows you into normal business email.
Raising volume because the mailboxes are "ready." Ready means allowed to send. It does not mean the ceiling has gone up.
Skipping the recheck. A DNS change after the last check can leave a domain unprepared. The 7-day window exists for that reason. [[4]](#sources)
Reading silence as success or failure. Most emails get no reply. [[14]](#sources)
No pause owner. When something looks wrong at 6 p.m. on a Friday, someone has to be allowed to stop it.

Next step

Start with the policy. Write the ceiling, the pause rules and the approver, then get a person to approve it. After that, pick your mailbox route and let the clock run: at least 14 days, usually about 3 weeks on managed mailboxes. [[2]](#sources)

If you are still deciding who to write to, run the free ICP assessment first. For how approvals, policies and kill switches fit together, see how Outlevo works. For the sending setup, read the Smartlead and managed mailboxes pages. For the longer treatment of volume and deliverability, go to cold email deliverability.