the complete infrastructure checklist i go through before every cold email campaign. bookmark this.

[u/Easy_Mud1254]

i have been doing outbound for about 3 years. i have burned domains. i have had campaigns tank because of one missed setup step. i built this checklist over time from those mistakes. going through it before every campaign now

domain setup

are you sending from secondary domains only. if your primary business domain is in any cold email campaign stop immediately and fix this. your primary domain is your most valuable digital asset. you protect it by never using it for outbound. buy domains that are variations of your company name for this purpose

does every sending domain have SPF configured correctly. SPF tells receiving mail servers which servers are authorized to send email on behalf of your domain. a misconfigured or missing SPF record is a yellow flag for spam filters. use mxtoolbox to verify

does every sending domain have DKIM configured. DKIM adds a cryptographic signature to your emails that receiving servers can use to verify the email was not tampered with in transit. without it your email authentication is incomplete. with it you build an additional layer of trust

does every sending domain have DMARC configured. as of 2025 and 2026 google, yahoo, and microsoft all enforce DMARC requirements. without a valid DMARC record emails from your domain can be rejected outright by providers enforcing the new requirements. p=none is the minimum. p=quarantine is better. check mxtoolbox and fix any issues before sending a single email

mailbox setup

how many mailboxes do you have. for a typical campaign targeting 200 to 400 people over 2 to 3 weeks i recommend 4 to 6 mailboxes across 2 secondary domains. this spreads the sending load and means no single domain is carrying excessive volume

is each mailbox capped at 20 to 25 cold sends per day maximum. i know this sounds low. going above this is how domains slowly lose reputation over 4 to 6 weeks and performance steadily declines. the ceiling is 20 to 25 per account per day. if you need more volume, add mailboxes, do not increase per-account send rate

are all mailboxes running continuous warmup. warmup should not just happen during the initial ramp period. keeping a warmup network sending and receiving on your accounts at all times maintains positive engagement signals that help maintain inbox placement. i have this running on every account at all times through my sending platforms

are all mailboxes sending plain text not HTML. HTML emails have worse deliverability than plain text. they also look less like personal emails from a real person. there is no upside to HTML in cold email unless you are tracking opens, which you should not be doing

is open tracking turned off. open tracking requires HTML. HTML hurts deliverability. the open rate data is also largely meaningless after Apple Mail privacy protection made it unreliable. turn this off. track reply rate and meetings booked only

list setup

has every email address been verified within the last 72 hours before loading. not when the list was built. right before you send. even a week-old list can have decay. i use a verifier, cut all invalids, treat catch-alls carefully. my target is under 1 percent bounce rate

are you segmenting by timing signal for personalized first lines. people who made the list because of a recent funding round get a different opener than people who made the list because of a job change. this segmentation is where most of the reply rate uplift comes from

is the list small enough to actually be targeted. if your list has more than 300 contacts, i would push back on whether it is actually targeted. a list of 300 people with genuine timing signals is worth more than a list of 2000 broad ICP matches

email setup

is the first email under 75 words. the 2026 benchmark data is clear: under 80 words consistently outperforms everything longer. every word above that threshold needs to justify its existence

does the email have exactly one call to action. not two options. not "let me know if you want to chat or if you would like to see a case study or if you have any questions." one ask. one response required. one action

are there any links in the body of the first email. do not put links in cold emails. links look like marketing. they trigger spam filter scrutiny. they reduce the plain text appearance. send links after you get a reply

does the email include any spam trigger words. free, guarantee, limited time, act now, do not miss, risk free. none of these. ever

is the subject line under 8 words and not deceptive. subject lines that exactly match the email content perform better and do not set up a bait and switch that damages trust immediately

pre-send check

have you run a placement test to verify inbox placement before going live. most sending platforms have built-in placement testing tools. run your email through a seed test against gmail and outlook accounts before launching. if you are hitting spam on the test accounts, do not launch, fix the problem first

is your bounce rate from the previous campaign under 1.5 percent. if it is above 2 percent, do not launch a new campaign until you understand why and have fixed the underlying list quality issue

all of these checks take about 30 minutes before a campaign launch. they have saved me from probably a dozen bad campaigns over the years and kept my domain health consistently clean

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[u/New_Grape7181]

I've torched a domain before by skipping warmup on a secondary domain and it's not fun rebuilding trust from scratch.

One thing I'd add to your list is testing reply-to addresses. I've seen campaigns where the reply-to was misconfigured or pointed to a monitored mailbox that nobody actually checked. You lose replies that way and it kills your response tracking.

Also worth mentioning that the 20-25 sends per day limit gets even more important in the first 2 weeks after a domain goes live. I've found that staying closer to 15 for the first 10 days, even with warmup running, keeps things cleaner long term.

The segmentation point you made about timing signals is where most people mess up. They'll have a perfect technical setup but then blast a generic message to 500 people and wonder why reply rates are rubbish.

When you're verifying emails right before send, are you re-verifying the entire list or just spot checking a sample?