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The Omnisend Email Subject Line Tester

Boost your email open rates: analyze and improve your subject lines with our free tester before sending out your next campaign.

Open form

Why test your subject lines?


of customers open emails based solely on the subject line. A great subject line makes or breaks whether your campaign even gets opened.


of customers mark an email as spam based on the subject line. Having too many emails marked as spam affects overall deliverability and sender reputation.


of customers say marketing emails influence their purchase decisions. Without an attention-grabbing subject line, a large share of such emails get lost in the inboxes.