Free tool · Outbound
Cold email subject-line tester
Paste your subject line. Get spam-risk, length checks, mobile preview, and a verdict in 3 seconds. Tuned for B2B cold outreach.
Tip: paste the exact subject — including any merge variables like {{first_name}}. The tester will treat variables as average-length substitutions (~5 chars).
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Gmail-style preview— chars · — words
B
Borrowsignal
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Hi {{first_name}}, spent 20 minutes pulling 7 UK SMEs incorporated in the last 5 days…
Checks
How this works. The tester applies 8 rules tuned for B2B cold email on Gmail / Outlook / Apple Mail: spam-word risk, length (chars + words), ALL CAPS, exclamation overuse, money signs, emoji, personal-token presence, and mobile-truncation. None of this is sent to a server — runs entirely in your browser.