Subject Line & Preview Text Tester
Free tool: Test email subject lines for length, spam words, and curiosity score. Get A/B test variant suggestions.
More Email Agency tools
- Email Campaign Calendar Generator — Free tool: Generate a monthly email calendar by niche with campaign types and subject line ideas.
- Email Deliverability Health Checklist — Free tool: Audit your email deliverability with prioritized fixes for authentication, list hygiene, and sending practices.
- Email Segmentation Ideas Generator — Free tool: Generate RFM and behavioral segment ideas with campaign suggestions for each segment.
- Klaviyo Flow Builder & Sequence Mapper — Free tool: Select email flows and get visual sequence maps with timing, copy suggestions, and conditional split recommendations.
- UTM & Email Naming Convention Generator — Free tool: Generate consistent UTM parameters and email naming conventions for better tracking and analytics.
- Welcome Flow ROI Calculator — Free tool: Calculate revenue potential of your welcome flow based on list size and conversion benchmarks.
Subject
Line & Preview Text Tester
Check length, spam words, and curiosity score.
tl;dr
Subject Line & Preview Text Tester Free tool: Test email subject lines for length, spam words, and curiosity score. Get A/B test variant suggestions.
Subject Lines Make or Break Opens
A great subject line is the difference between 15% and 40% open rates. Test before you send.
#
What You Get
Spam word detection with alternatives.
Curiosity/engagement score out of 10.
A/B test variants for split testing.
Never miss a customer call
Writly answers when you can't, books the work, and sends the details to your phone.
More Email Agency tools
email campaign calendar generator
free tool: generate a monthly email calendar by niche with campaign types and subject line ideas.
email deliverability health checklist
free tool: audit your email deliverability with prioritized fixes for authentication, list hygiene, and sending practices.
email segmentation ideas generator
free tool: generate rfm and behavioral segment ideas with campaign suggestions for each segment.
klaviyo flow builder & sequence mapper
free tool: select email flows and get visual sequence maps with timing, copy suggestions, and conditional split recommendations.
utm & email naming convention generator
free tool: generate consistent utm parameters and email naming conventions for better tracking and analytics.
welcome flow roi calculator
free tool: calculate revenue potential of your welcome flow based on list size and conversion benchmarks.
Frequently asked questions
30-50 characters for mobile. Shorter ensures full display on small screens.
Yes, sparingly. One relevant emoji can boost opens, too many looks spammy.
The curiosity score is a measure of how engaging and intriguing your subject line is, rated out of 10 based on language and structure.
The tool uses a comprehensive list of commonly flagged spam words and phrases that email filters target to analyze your subject line.
Currently, the tool supports testing one subject line at a time, but you can quickly switch between different lines to compare results.
A/B test variants are alternative subject lines generated by the tool to help you determine which version performs better in terms of open rates.
The tool does not save previous tests for privacy reasons, but you can export results to your local device.
The spam word detection is based on industry-standard lists and is regularly updated to maintain accuracy.
Ready to scale your business?
Join hundreds of businesses using Writly to win more contracts.
Try Writly call deskExample: Subject Line & Preview Text Tester in action
A marketing manager needs to optimize an email campaign's subject line to improve open rates.
Sample input
- Subject Line: Unlock the Secrets of SEO Today!
- Preview Text: Discover strategies to boost your search rankings.
Result
Length: 37 characters Spam Words Detected: None Curiosity Score: 7.5/10 A/B Test Variants: 1. Uncover SEO Secrets Today! 2. Boost Your SEO Rankings Now!
About Subject Line & Preview Text Tester
Subject lines are crucial in determining whether an email gets opened or ignored. With average open rates ranging from 15% to 40%, optimizing your subject line can significantly impact your campaign's success. This tool evaluates your subject line's effectiveness by checking for spam words that might trigger filters, ensuring your message reaches the inbox. Additionally, it provides a curiosity score, helping you gauge how intriguing your subject line is to potential readers. By offering A/B test variants, you can experiment with different approaches to maximize engagement.
How it works
- Enter your email subject line and optional preview text into the tool.
- The tool analyzes the length to ensure it fits within standard email client displays.
- It checks for common spam words that may affect deliverability.
- The tool calculates a curiosity score based on language engagement metrics.
- It suggests A/B test variants to help improve open rates.
When to use it
- Email marketers preparing a new campaign.
- Small business owners crafting newsletters.
- Content creators testing engagement strategies.
- E-commerce businesses optimizing promotional emails.