Fardeen Karim
How to write a cold email that gets replies
A simple four-part structure for cold emails, how to personalise without spending all day, and how to write follow-ups people actually answer.
Fardeen KarimRead A cold email subject line has one job: look like a normal email from a real person. It isn't an ad headline. The moment it reads like marketing, the reader knows what's inside and moves on.
The rules I follow
- Short. Two to five words is plenty. Phones cut long subjects off.
- Lowercase or sentence case. Title Case Looks Like A Newsletter.
- Specific to them. Their company, their market or their problem, rather than your product.
- True to the email. A subject that misleads breaks US law as well as trust, and it earns the "report spam" click.
How long should a cold email subject line be?
Short enough to survive a phone, which can cut a subject off at around 35 to 40 characters. Put the part that matters first, and if you can say it in three words, stop there.
Does personalising the subject help?
Only when it's real. Their first name in the subject is something any tool can do, and people know it. A line you could send unchanged to 500 people gets treated that way, so a detail about their company or market does far more than a name.
Example subject lines by situation
These are examples I've written for this article to show the patterns, not results from a test. Swap in your own details.
You've noticed something about them
- new dallas location
- your pricing page
- hiring two sdrs
A plain question
- question about {{companyName}}
- who handles outbound?
- worth a look?
The problem you solve
- missed calls after hours
- slow invoice follow-up
- leads going cold
Someone they know of
- similar to {{competitorName}}
- idea from another agency
What I avoid
- Fake replies and forwards. "Re:" on a first email is a lie that the reader catches in one second.
- False urgency. "Last chance" from a stranger reads as spam.
- Heavy punctuation and emoji. They signal marketing, even when they don't trip a filter.
- Your company name. It's already in the From line, and they don't know it yet.
Do "spam words" matter?
Less than people think. Modern filters mostly judge your domain's reputation, your authentication and how people react to your email. One word won't sink a healthy domain, but a subject full of them looks wrong to humans anyway. The free subject line analyzer and spam word checker are good for a quick look.
Keep the same thread for follow-ups
Send follow-ups as replies in the same thread, with the same subject. It keeps your earlier email in view and it's what a person would naturally do.
Test it properly
Test one subject against another on the same list in the same week, with the same body. Judge by replies more than opens, since open numbers mislead. Small differences on a few hundred people are usually noise, so look for clear gaps before changing anything.
mailzy campaigns let you run A/B variants on a step and show results per variant. If you write a template with a field like {{competitorName}}, every lead needs that column filled, or a fallback. See campaigns.