Quality Tests
Learn about all 13 automated quality tests that EmailTestLab runs on your emails.
Quality Tests
EmailTestLab runs 13 comprehensive quality tests on every email. Each test checks a specific aspect of email quality, deliverability, or design.
Overall Quality Score
Your overall score is calculated as an average of all test scores:
- 90-100: Excellent - Your email is ready to send
- 70-89: Good - Minor improvements recommended
- 50-69: Fair - Several issues need attention
- Below 50: Needs Work - Significant issues found
1. Spam Score
What it checks:
- Content analysis for spam trigger words
- Image-to-text ratio
- HTML code quality
- Overall deliverability risk
Scoring:
- Risk level from 0-10 (lower is better)
- Score of 0-3: Excellent deliverability expected
- Score of 4-6: Some risk, review recommendations
- Score of 7-10: High risk of spam folder
2. Link Validation
What it checks:
- All links are valid URLs
- Links resolve correctly (HTTP status)
- No broken or malformed links
Results show:
- Total links found
- Valid vs invalid links
- Individual link status
3. Domain Authentication
What it checks:
- SPF (Sender Policy Framework) record
- DKIM (DomainKeys Identified Mail) signature
- DMARC (Domain-based Message Authentication) policy
Requires:
- Enter your sender domain in the Editor tab
- We'll check DNS records for authentication setup
4. Subject Line Analysis
What it checks:
- Character length (optimal: 30-70 characters)
- Spam trigger words
- ALL CAPS usage (triggers spam filters)
- Excessive punctuation (!!!, ???)
Best practices:
- Keep under 50 characters for mobile
- Front-load important words
- Avoid spam triggers like "FREE!!!" or "ACT NOW"
5. Preview Text Optimization
What it checks:
- Preview text exists
- Optimal length (40-130 characters)
- Not repeating the subject line
- No "View in browser" or utility text
Why it matters: Preview text appears next to your subject in the inbox - it's your second chance to convince someone to open.
6. Email Size & Gmail Clipping
What it checks:
- Total HTML file size
- Gmail 102KB clipping threshold
- Size breakdown
Gmail clipping: Emails over 102KB are clipped with "[Message clipped] View entire message" - this kills engagement. We show a clear warning if you're at risk.
7. Plain Text Ratio
What it checks:
- Text-to-HTML ratio percentage
- Whether ratio meets spam filter expectations
Target: 25-30% text-to-HTML ratio
Low text ratios (too much HTML, too little actual content) can trigger spam filters.
8. Unsubscribe Link
What it checks:
- Visible unsubscribe link in email body
- List-Unsubscribe header presence
- One-click unsubscribe support
Legal requirement: CAN-SPAM and GDPR require easy unsubscribe options. Missing one can result in legal issues and spam complaints.
9. HTML/CSS Validation
What it checks:
- Email-compatible HTML structure
- Deprecated HTML tags
- Unsupported CSS properties
- Inline CSS percentage
- Media query usage
Email-specific: Email HTML is different from web HTML. Many CSS properties don't work in email clients (especially Outlook).
10. Mobile Optimization
What it checks:
- Responsive design elements
- Touch-friendly button sizes (44x44px minimum)
- Readable font sizes (14px+ recommended)
- Single-column layout support
- Viewport meta tag
Stats: Over 60% of emails are opened on mobile devices.
11. Personalization Tokens
What it checks:
- Merge tag detection ({{first_name}}, {{company}}, etc.)
- Whether personalization is used
- Token count
Why check: Personalized emails have 26% higher open rates. We detect if you're using personalization tokens in your content.
12. Dark Mode Support
What it checks:
@media (prefers-color-scheme: dark)CSS- color-scheme meta tag
- Transparent image usage
- Background color choices
Why it matters: 80%+ of users have dark mode enabled. Poor dark mode support can make logos invisible and text unreadable.
13. Spell Check
What it checks:
- Spelling in subject line
- Spelling in preview text
- Spelling in body content
- Word count
Impact: Typos hurt credibility and can trigger spam filters.
Running Tests
All 13 tests run automatically when you click "Run Test" in the Editor. Results appear in the Email Testing tab, where you can:
- See overall score
- Click each test for detailed results
- View issues and recommendations
- Filter and sort by score