Email Subject Line Tester
Test your email subject line for length, mobile and desktop truncation, spam trigger words, and readability. Instant, rule-based scoring that runs entirely in your browser.
Your subject line
What makes a follow-up subject line work
For a follow-up after a real conversation, the best subject lines look like something a colleague would send: specific, lowercase-calm, and anchored to the call — “the pricing breakdown you asked for” beats “Great connecting!” every time. Aim for 30–50 characters so the whole thought survives a phone screen, put the meaningful words first, and skip urgency theatrics; the prospect already knows who you are.
Replying in the existing thread (Re: your original subject) is often stronger than any new subject — it carries the context of the conversation with it.
FollowClose turns your sales call transcripts into personalized 5-email follow-up sequences — written, scheduled, and ready to send.
Try it with your next call →