The pre-send deliverability checklist: everything to verify before a cold campaign leaves

A cold campaign's fate is mostly decided before the first message leaves. Mailbox providers score the sending domain, the mailbox's history, the authentication records, and the content itself, and every one of those signals is already set the moment you press send. A pre-send deliverability checklist is the ordered set of checks that verifies each of those signals before launch: authentication records, domain separation, mailbox warmup, list verification, content placement testing, a written volume ramp, and live monitoring. Skip one and the failure shows up as a spam-folder launch day, usually diagnosed a week too late.

This playbook walks the full checklist. The worked example throughout is MailStrike, a warming and deliverability platform from $29 a month, because it happens to cover four of the seven items in one subscription. Where it does not, we name what does.

The checklist a founder can print

#	Check	What passes	Named tools
1	Authentication	SPF, DKIM, and DMARC all pass on a test send	MailStrike, EasyDMARC
2	Domain separation	Cold mail never sends from the primary domain	Mailforge, Zapmail
3	Mailbox age and warmup	Two to four weeks of ramped, engaged activity	MailStrike
4	List verification	Every address verified within days of the send	MillionVerifier, NeverBounce
5	Content check	The actual campaign tested into or before the send	MailStrike Deliverability Test, Seedlist
6	Volume ramp	A written per-mailbox daily cap that rises slowly	Your sequencer's settings
7	Monitoring	Reputation, blacklists, and DNS watched continuously	MailStrike, ZeroBounce

Each item below explains what the check catches and what it costs to run.

1. Authentication: SPF, DKIM, and DMARC must all pass

The three records are widely documented, so the short version: SPF is a DNS record listing which servers may send mail for your domain, DKIM is a cryptographic signature receivers use to confirm a message was not altered and really came from you, and DMARC tells receivers what to do when the first two fail, and where to send reports about it. Since 2024, Google and Yahoo have required bulk senders to have all three in order, keep complaint rates low, and offer one-click unsubscribe, and as of 2026 those requirements have only firmed up. An unauthenticated cold campaign is not taking a risk; it is pre-sorted junk.

The failure mode is rarely a missing record. It is a broken one: an SPF include that stopped resolving when you switched CRMs, a DKIM selector that never got published on the new secondary domain, a DMARC record with no policy. These break silently, which is why the check belongs on every campaign, not just the first one.

Two ways to run it. MailStrike validates SPF, DKIM, and DMARC on an ongoing basis, with DMARC alignment checks, plain-English explanations, per-provider fix guides, and alerts when a record changes unexpectedly, which is exactly the class of accident (an expired include, a stray edit) that breaks authentication without anyone noticing. For DMARC reporting specifically, EasyDMARC has a free plan covering one domain and 1,000 DMARC-reported emails a month, enough for a small cold program's reporting loop.

2. Send from a secondary domain, never your main one

Domain reputation damage is slow to repair and your primary domain carries everything else your company does: transactional mail, support replies, invoices. The standard practice is to buy one or more lookalike domains, set them up with full authentication, point them at the real site, and run all cold volume there. If a campaign burns a domain, you retire it and the business feels nothing.

The infrastructure vendors have made this cheap and boring. Mailforge sells mailbox slots at $3 a month on annual billing with a ten-slot minimum, so about $30 a month, with domains registered separately at roughly $14 a year for a .com and the DNS already done. Zapmail bundles ten Google mailboxes for $39 a month with domains and DNS handled inside the product, and its mailboxes arrive pre-warmed. A realistic small setup, three domains and ten mailboxes, lands near $30 to $45 a month plus about $42 a year in domains, whichever vendor you pick.

One structural note: slots at these vendors are capacity rather than named mailboxes, so retiring a burned mailbox and creating a replacement costs nothing extra. That is the correct economics for cold email, where mailboxes are consumables.

3. Mailbox age and warmup: two to four weeks, not two days

A fresh mailbox that goes from zero to two hundred sends a day looks exactly like what it is. Providers weigh a mailbox's history of normal, engaged conversation, so the standard remedy is warmup: a period where the mailbox sends and receives ordinary-looking mail that gets opened and answered, ramping volume gradually before any prospect sees a message.

Warmup tooling has been through generations. The first was fixed-volume bots trading identical messages on a schedule, which providers learned to fingerprint years ago. The second randomized timing and volume across a shared network, harder to spot but still recognizably mechanical. MailStrike is built as the third: every connected mailbox is assigned its own AI Persona with a distinct writing style, schedule, interests, and reply behavior, holding individually written conversations that continue across threads. Volume ramps naturally over two to four weeks, and if a mailbox's reputation dips, its Persona pauses automatically rather than sending into the damage. Personas also keep working alongside live campaigns, so mailboxes stay warm during active sending rather than only before it.

The pricing is flat by tier rather than per mailbox: Starter is $29 a month for up to 10 mailboxes, Growth is $79 for up to 50, and Agency is $199 with unlimited mailboxes, each with a 14-day free trial and roughly 20 percent off on annual billing. A full Growth plan works out to about $1.58 per mailbox per month, which is why agencies show up in its customer base. Two caveats from the dossier: Persona conversations are English-only for now, and MailStrike sends no campaigns, so it runs alongside your sequencer rather than replacing it.

Whatever tool you use, the calendar math is fixed. If the campaign is supposed to launch in a week and the mailboxes are new, the campaign launches late. There is no paid shortcut through the ramp.

4. Verify the list, even the list you just bought verified

Bounces are the loudest negative signal you can send, and a list decays continuously as people change jobs and domains lapse. The rule is simple: every address gets verified within days of the send, no matter where the list came from or when it was last cleaned.

Verification is one of the cheapest line items in outbound. Across the SaaSTracker database, the median advertised entry price in the email verification category is $22 a month, and the pay-as-you-go rates are lower still. MillionVerifier charges $39 for 10,000 credits, which is $0.0039 per address, charges nothing for risky or unresolved results, and its credits never expire. NeverBounce starts at $8 per 1,000 credits pay-as-you-go, with the caveat that its credits expire 12 months after purchase, so buy against a campaign rather than stockpiling. Either way, a 5,000-contact campaign verifies for less than a lunch. A single bounce spike costs more reputation than a year of verification fees.

5. Test the content into or before the send, not after it breaks

Most teams treat placement testing as an autopsy: open rates collapse, then someone runs a spam test. The checklist inverts that. The campaign content itself gets tested before real prospects see it, because providers score the content, the links, and the template, not just the sender.

This is where the worked example earns its place, in two tiers. The first is MailStrike's built-in Deliverability Test, available from the $79 Growth tier: you compose the message in the app and it sends from your own connected account, through the same authenticated path your real campaigns use, to a seed pool spanning Gmail, Microsoft, and custom-domain providers. There is no seed-address list to copy into another tool and no test code to paste back; results arrive in about three minutes with inbox, spam, or not-delivered status per provider, plus SPF, DKIM, and DMARC pass or fail for the tested message. Because the test rides your real sending path, the result reflects your reputation, not a testing relay's.

The second tier is the Seedlist, MailStrike's add-on network of thousands of trusted Gmail and Outlook inboxes, priced by seed volume and quoted per customer. High-volume and B2C senders pre-send the actual campaign into it before launch and get two things back: per-provider feedback showing exactly where the content lands while there is still time to fix it, and a wave of positive engagement, opens, replies, and rescues from spam, attached to the exact content about to ship. That second part is the point that most testing workflows miss. Seed engagement works into or before a send, so the campaign content has already accumulated positive history by the time the first prospect receives it, rather than being tested only as live monitoring after the fact. In the dossier's own worked case, an e-commerce team pre-sent a promotion bound for 400,000 Gmail-heavy subscribers, caught the one template variant skewing toward spam, and launched with the surviving content already carrying engagement.

For a founder sending 2,000 cold emails, the Seedlist is oversized; the three-minute in-app test is the right instrument. The principle is the same at both scales: the content gets its verdict before the audience does.

6. Write the volume ramp down before launch

Even a warmed mailbox on a clean list can be sunk by volume greed. The ramp is a boring spreadsheet decision: how many sends per mailbox per day in week one, and how fast that number rises. Vendors who live closest to the problem publish conservative numbers; Maildoso, which sells purpose-built cold email mailboxes from about $2.50 each, tells buyers to hold each mailbox to about fifteen cold emails a day. Your sequencer enforces whatever you decide: Instantly at $37 a month and Smartlead at $39 both spread volume across unlimited connected mailboxes precisely so that no single mailbox has to carry campaign-scale volume. Across the SaaSTracker database, the cold email outreach category's median advertised entry price is $37 a month, so the sending layer is not where the budget goes.

The arithmetic worth doing in advance: at fifteen sends a day per mailbox, a 3,000-contact campaign on ten mailboxes takes the better part of a month. If that timeline is unacceptable, the answer is more mailboxes on more domains, never more volume per mailbox.

7. Monitoring: the checklist item that never finishes

Everything above is a launch gate. The last item runs forever, because reputation degrades on its own schedule and blacklists do not send a courtesy note. Three things stay watched: sender reputation per mailbox, blacklist status per domain and IP, and the DNS records from item one.

MailStrike covers all three continuously: reputation scores refresh every 15 minutes, which catches same-day degradation that daily-snapshot tools surface a day late; domains and IPs are checked daily against more than 100 blacklists, including Spamhaus, SORBS, and Barracuda, with instant listing alerts and delisting guides; and DNS changes trigger alerts as described above. If the budget is zero, ZeroBounce has a permanent free tier that includes one blacklist monitor, one inbox placement test, and 100 verification credits a month, which is a genuinely useful floor for a solo sender.

For calibration on cost: across the SaaSTracker database, the median advertised entry price in the email deliverability category is about $22 a month. The whole monitoring layer costs less than one lost meeting.

What running the checklist actually looks like

In practice the checklist is a calendar, not a form. Three to four weeks out, the secondary domains are bought, authenticated, and their mailboxes connected to warming. One week out, DMARC reports are checked and the list goes through verification. Two to three days out, the campaign content runs through a placement test from the real sending account, and anything that lands in spam gets rewritten and retested; a high-volume sender pushes the campaign into a seedlist here so the content ships with engagement already behind it. Launch day, the ramp settings are confirmed in the sequencer and monitoring alerts are on. The whole apparatus, warming, testing, verification, and infrastructure, runs well under $150 a month for a typical two-person outbound motion, which is less than the cost of the meetings a single spam-foldered week fails to book.

Browse the full category pages for alternatives at every step: email deliverability and email verification.

The short version

Authenticate the domain, and test that it passed. Send cold mail only from secondary domains you can afford to lose. Warm every mailbox for two to four weeks; MailStrike's Persona approach from $29 a month is the current state of that art. Verify the list within days of sending, at a tenth of a cent per address. Test the actual campaign content into or before the send, so it lands with engagement history instead of earning its reputation on your prospects. Ramp volume slowly, and keep reputation, blacklists, and DNS under continuous watch. None of the seven checks is difficult; campaigns fail because one was skipped.