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Paste a subject line to check its length, wording and spam triggers, with a fix for each issue.
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The subject is the first thing a reader and a spam filter see. This tester checks the parts you control against simple rules you can read.
Phones often show only the first 30 to 40 characters of a subject, so the words that matter go first. For cold email, three to five plain words work well: the topic, their company, or a question.
Write it the way a colleague would. "Hiring plans at Acme" reads like a note, while "Unlock Explosive Growth Today" reads like an ad.
Every subject starts at 100. Each rule that fails takes off the points shown beside it, for length, capitals, exclamation marks, spam words, emoji, fake reply prefixes and more.
The score measures writing habits. It cannot predict your open rate, and it knows nothing about your audience or your sender reputation.
Remove "Re:" or "Fwd:" unless the email really continues a thread. Swap capitals and exclamation marks for sentence case.
If you use merge fields like {first_name}, check that every lead has a value or set a fallback. A blank or a raw placeholder in a subject looks careless.
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Under about 40 characters is a safe target, since phones often cut subjects after 30 to 40 characters. Many cold emails use three to five words. Put the important words first in case the end is hidden.
80 or above means the subject avoids the common problems this tool checks. It is a writing check rather than an open rate prediction, so test real subjects with your own audience.
No. "Re:" or "Fwd:" on a first email suggests a conversation that never happened. Readers spot the trick, which costs trust and can lead to spam complaints. Keep it for real replies.
Leave them out of cold emails. Emoji make a subject look like a newsletter, and they can render differently across devices and apps. They are more common in brand newsletters sent to subscribers.
It helps when the detail is relevant, such as their company or a recent event. A first name alone is common and easy to recognize as a merge field. Set a fallback so nobody sees a blank.
Rarely on its own, because filters weigh sender reputation and authentication more heavily. Spam phrases, capitals and exclamation marks together still make an email look like bulk promotion.
