Cold email basics · Updated Oct 9, 2026
Subject lines that get opened
In short
A good cold subject line is short, plain and specific, like one a colleague would write. Its job is to get the right person to open the email honestly: a subject that tricks people gets opened once, then reported.
What works
- Short: a few words, under 60 characters, so it isn't cut off.
- Plain, in sentence case or lower case, like a note from a person. No capitals for emphasis, no “!”, no emoji.
- About them: their company, their role or something that just happened, often with a variable like
{{company_name}}. - Honest: the email delivers what the subject promises.
- No sales words such as free, discount, guarantee or risk-free.
Examples
Question about {{company_name}}- Good
- Why: Specific and calm, and it invites a reply.
hiring in Lisbon- Good
- Why: Shows you noticed something real about them.
{{first_name}}, onboarding emails- Good
- Why: Names the topic the email is about.
URGENT: last chance!!!- Avoid
- Why: Capitals, “!” and false urgency: filters and people both distrust it.
Re: our call- Avoid
- Why: A fake reply to someone you never spoke to. Deceptive, and filters spot it.
Free audit, 50% off this week- Avoid
- Why: Sales words and a discount read as an ad.
Follow-ups
Leave a follow-up's subject empty: it's sent as a reply in the same thread (“Re:” and step 1's subject), so the reader sees your first email under it. That “Re:” is honest, because it really is a reply. Give a follow-up its own subject only to start a new thread. The sequence
Test yours
- Inbox readiness checks each subject as you write it: length, capitals, “!”, emoji, spam words and a fake “Re:” or “Fwd:”. Inbox readiness
- Try two subjects as A/B variants of step 1 and let SendPath pick the winner by reply rate. A/B variants
- Spintax gives each contact one of a few versions:
{{RANDOM | quick question | a question}}.
Judge a subject by replies, not opens. Open tracking is off by default because it can lower inbox placement, and some mail apps open every email automatically, so open counts run high.
If something's wrong
- Inbox readiness flags the subject.
- Open the item: it names what to change (length, capitals, a “!”, an emoji or a spam word). Fix with AI suggests a calmer version.
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Related
Writing emails that get repliesWhat a good cold email looks like, a simple structure, and how SendPath AI helps you write one.Following up without annoyingHow many follow-ups to send, how far apart, what each one should say, and when SendPath stops them.Write your emailsThe email editor, variables, inbox readiness, previews and test emails.
Something missing or wrong? Email support@sendpath.ai.