Your First Cold Campaign: A Deliverability Guide for Founders

You have a product, a list of people who might want it, and an email you have rewritten nine times. The temptation is to load the list into a sending tool and press go.

This guide covers the work that should happen first. None of it is complicated, but most of it is invisible, and so is the cost of skipping it: your emails land in spam, nobody replies, and you conclude cold email does not work for your business. Often the message was fine. It just never reached a person.

1. Why the first send matters

Gmail, Outlook and Yahoo decide where your email goes partly on the reputation of the domain and server that sent it. A brand new domain has no reputation. It is not good or bad yet, just unknown, and unknown senders are treated with caution.

Your first few weeks of sending are when that reputation forms. If a new domain’s first act is sending a few hundred identical emails to strangers, some of which bounce and some of which get marked as spam, that becomes the record providers judge you by. Recovering is possible but slow. Google’s own guidance notes that “it can take time for improvements in spam rate to reflect positively on spam classification”.

So the aim of everything below is to make your early sending look like what it should be: a real person writing to a small number of people who might reasonably want to hear from them.

2. Use a separate sending domain or subdomain

Do not run your first cold campaign from the domain your company uses for everything else. Your main domain carries invoices, password resets, investor updates and support. If a campaign goes badly, you do not want any of that affected.

You have two options. A separate domain that is clearly related to your brand, such as getyourbrand.com, gives the most protection. A subdomain such as mail.yourbrand.com keeps the brand connection but is less fully separated from your main domain’s reputation.

Either way, set it up like a real business address: point the domain at your website or a simple page that explains who you are, use a mailbox in your real name, and add a signature. A domain with nothing behind it looks exactly like what spammers use.

Register it early, because it needs time to be set up and warmed before it sends anything that matters. If you want the stages in order, from buying the domain to the first send, this cold email setup guide walks through each one.

3. SPF, DKIM and DMARC in plain words

These three DNS records let a receiving server check that an email claiming to be from your domain really is.

• SPF is a list, published on your domain, of the servers allowed to send email for it. Google Workspace and Microsoft 365 tell you exactly what to add.
• DKIM adds a digital signature to every email. The receiving server checks it against a public key on your domain. If it matches, the email came from you and was not altered.
• DMARC tells receiving servers what to do when an email fails those checks, and where to send reports. A policy of p=none means “do not block anything yet, just report”.

It is worth reading the requirements at the source. Google’s email sender guidelines ask all senders to set up SPF or DKIM, and anyone sending 5,000 or more messages a day to personal Gmail accounts to set up SPF, DKIM and DMARC, noting the DMARC policy “can be set to none”. Yahoo’s sender best practices ask all senders for SPF or DKIM at a minimum, and bulk senders for both plus a DMARC policy of at least p=none.

Your first campaign is probably well below the bulk threshold. Set up all three anyway. It takes an afternoon and removes an easy reason for a provider to distrust you.

To check before you send: email a test from your new mailbox to a personal Gmail address, open it, choose “Show original” from the three-dot menu, and look for SPF, DKIM and DMARC all showing PASS. If one does not, fix it first. The usual causes are a typo in a record, two SPF records where there should be one, or a DKIM key that was generated but never published.

4. Warm up before you send

Warming up means building a sending history gradually before a new mailbox does real work: ordinary, low-volume email that gets opened and replied to, increasing a little each day.

Google’s guidelines have a section headed “Increase sending volume slowly to avoid delivery problems”. It says: “Start with a low sending volume to engaged users, and slowly increase the volume over time”, and “Avoid introducing sudden volume spikes if you do not have a history of sending large volumes.”

You can warm up by hand, using the mailbox for real conversations with colleagues, friends and existing contacts who will reply. It works, but it is slow and easy to forget. Or you can use a warmup tool, which connects your mailbox to a network of others that send to each other, open, reply and move messages out of spam. Several exist; pick one you are comfortable giving access to your mailbox, and read what it does with your data.

No major provider publishes a required warmup period. As a rough guide, I would allow at least two to three weeks before a first campaign, but the better test is behaviour: is the mailbox sending steadily, getting replies and staying out of spam? If so, you can start. Keep warmup running after launch too.

5. Keep the list clean

A bounce happens when you send to an address that does not exist. Providers read lots of bounces as a sign the list was not built from people who know you, a common spam pattern.

Before your first send:

• Verify every address with an email verification service and remove anything invalid. On a first campaign, leave out “catch-all” and “unknown” results too.
• Drop role addresses such as info@ and sales@. Several people often read them, and any of them can mark you as spam.
• Check relevance. A smaller list of people with a real reason to care beats a large, loosely matched one, for replies and for complaints.

After each send, remove every address that bounced and never retry hard bounces. If someone asks not to be contacted, remove them at once and keep a record so they are not added back. Yahoo asks bulk senders to honour unsubscribes within two days; there is no reason to be slower.

Rules on cold email also vary by country, especially for writing to individuals rather than companies. Check what applies to you and your recipients before you start.

6. Write like a person

Spam filters read your content as well as your setup, and so do the people you write to. The same habits help with both.

• Keep it short: who you are, why this person, and what you are asking.
• No attachments. An attachment from a stranger is a classic risk signal. Offer to send it instead.
• Few links, ideally none, and no images or tracking in the first email. Plain text with a simple signature looks like normal correspondence.
• One clear question. “Is this a problem for you at the moment?” is easier to answer than a menu of options.
• Make saying no easy. “If this is not relevant, reply ‘no’ and I will not write again” gives annoyed readers an alternative to the spam button.
• Personalise for real. Identical text sent to hundreds of people is a pattern filters recognise. One sentence that could only have been written to that person helps both delivery and replies.

Read it out loud before sending. If it sounds like an advert, rewrite it.

7. The first week: volume, what to watch and when to pause

Start small and grow steadily. There is no official daily number for a new mailbox, so treat any figure you are given as a guess. A cautious approach is a few dozen emails a day per mailbox in the first week, increasing only while the signals below look healthy. Google advises you to “send email at a consistent rate” and warns that “immediately doubling previously sent volumes suddenly could result in rate limiting or reputation drops”. Spread sends across the working day rather than firing them all at 9am.

Watch these every day:

• Bounces. A cluster of them means your list source is the problem. Stop and re-verify before continuing.
• Replies. Read every one, including the negative ones; they show you are reaching real people. No replies at all can mean poor targeting, but it can also mean you are in spam, so test where your emails land.
• Spam complaints. Google asks all senders to keep the spam rate reported in Postmaster Tools below 0.3%, and recommends staying below 0.10% and never reaching 0.30%. Yahoo asks bulk senders to stay below 0.3%. That is three complaints per thousand emails, so on a small campaign one or two complaints matter.
• Server errors. If your tool shows deferrals or rejections, read the message. Google’s advice is that if messages start bouncing or being deferred, “reduce the sending volume until the SMTP error rate decreases”.

Google Postmaster Tools is free and shows Gmail’s view of your domain, including spam rate, once you send enough to Gmail users for data to appear. Set it up on day one.

Pause if bounces climb, if complaints are more than a rare event, if replies suddenly stop, or if your own test emails start landing in spam. Pausing for a few days costs very little. Sending through a problem can cost you the domain.

8. One-page pre-send checklist

Tick every line before your first real send.

Domain and mailbox

• Sending domain or subdomain separate from your main business email
• Domain points to a real site or a page explaining who you are
• Mailbox in your real name, with a simple signature

Authentication

• One SPF record published
• DKIM set up and signing
• DMARC published (p=none is a fine start)
• Test email to Gmail shows all three passing

Warmup

• Mailbox has built up sending gradually
• Warmup keeps running after launch

List

• Every address verified; invalid, unknown and role addresses removed
• Every contact has a clear reason to hear from you
• You know the rules for the people you are emailing

Message

• Short, plain text, no attachments, few or no links
• One clear question and an easy way to say no
• Real personalisation per recipient

First week

• Small daily volume, spread across the day
• Google Postmaster Tools set up
• Bounces, replies and complaints checked daily
• You know what will make you pause

Running cold email alone is a lot of small jobs. Each one is within reach of a single founder with an afternoon to spare, and together they give your carefully written message a fair chance of reaching the person you wrote it for.