What is cold email?
Cold email is a one-to-one business email sent to someone you have no prior relationship with, usually to start a sales conversation. Done well, it is short, relevant to a specific problem the recipient has, sent in small volumes from an authenticated domain, and easy to decline.
Cold email versus spam
The difference is relevance and volume. A cold email is written to one person for a reason that applies to them. Spam is the same message sent to thousands of people who never had a reason to get it. Mailbox providers judge by behaviour: if recipients mark your messages as spam, you are a spammer whatever you intended. Google asks all senders to keep the spam rate reported in Postmaster Tools below 0.3%.
Anatomy of a first email
Here is a worked example for a company selling a review-management service to dental practices:
Subject: your Google reviews
Hi Priya, I was looking at practices in Bristol and noticed yours has strong reviews but none replied to since spring. Practices that reply tend to look more active to people comparing dentists. Would it be useful if I sent over three draft replies you could use as a starting point? No worries if not.
What makes it work:
- A real reason drawn from something checkable (the review page).
- One idea, not a feature list.
- A small ask that costs nothing to accept.
- An easy no.
No links, no attachments and no images in a first email also help deliverability.
The numbers to measure
| Metric | Formula | What it tells you |
|---|---|---|
| Bounce rate | Bounces / sent | List quality |
| Reply rate | Replies / delivered | Relevance of targeting and message |
| Positive reply rate | Interested replies / delivered | Whether replies are worth anything |
| Spam complaint rate | Complaints / delivered | Whether you are welcome |
Open rates are unreliable because privacy features load tracking images automatically. Reply rate is the number to watch.
Common mistakes
- Sending from your main domain at volume. A reputation problem then affects your invoices and support mail too.
- Skipping authentication. Gmail and Yahoo require SPF or DKIM from every sender, and SPF, DKIM and DMARC from bulk senders. Mail that fails can be sent to spam or rejected.
- Unverified lists. Bounces damage reputation faster than anything else.
- Fake personalisation. "I loved your recent post" with nothing specific is worse than no personalisation.
- No stop rule. Following up after someone said no is how complaints happen.
Related terms
Cold email lives or dies on email deliverability, and is usually sent as part of an email sequence.
How Sluice handles it
Sluice drafts first messages from what each person actually wrote or did, and scores every draft with a reason before it can be queued, including one you write yourself. It sends only through Gmail or Outlook accounts you connect ($10.80 a month per connection) and only messages you approve. For writing from a prospect's own words, see buying signals that actually convert.
Questions people ask
- Is cold email legal?
- Rules vary by country. B2B cold email is lawful in many places with conditions, such as identifying yourself, giving a way to opt out and honouring it. Some countries are stricter, so check the rules where your recipients are.
- How long should a cold email be?
- Short enough to read on a phone without scrolling. A few sentences usually: why you are writing to them, one observation or offer, one easy question.
- How many follow-ups should a cold email have?
- Two or three, spaced a few days apart, each adding something new. Stop at once on any reply, especially a no.
Sources
Try it on your own market
Sluice quotes the worst-case price before anything runs and charges only for lookups that found something, so finding out costs close to nothing.
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