Email Subject Line Tester
Visualize your email on Mobile and Desktop before you send. Detect spam triggers and truncation issues instantly.
Why Subject Line Testing Matters
Your subject line is the gatekeeper of your email marketing. 47% of recipients open emails based on the subject line alone, while 69% report email as spam based solely on the subject line.
Common Spam Trigger Words to Avoid
Modern spam filters are sophisticated, but certain words still raise red flags, especially when combined with poor domain reputation. Our tool checks for common offenders:
- Financial: $$$, Cash, Credit, Income, Price, Lowest.
- Urgency: Act Now, Urgent, Instant, Limited Time.
- Gimmicks: Free, Guarantee, Winner, Risk-free.
- Formatting: ALL CAPS, excessive punctuation (!!!).
Optimal Length: The Sweet Spot
The "Goldilocks zone" for email subject lines is between 30 and 50 characters. This is short enough to be fully visible on most iPhone and Android notifications, but long enough to convey meaning.
Frequently Asked Questions
Is it okay to use emojis?
Yes, sparingly. Emojis can increase open rates by attracting attention, but using too many can trigger spam filters or make your brand look unprofessional.
What is A/B testing?
A/B testing involves sending two different subject lines to a small segment of your list to see which one performs better, then sending the winner to the rest of the list.