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Test email deliverability

Request

Comprehensive email deliverability testing that analyzes your email content for:

  • Spam score using SpamAssassin (industry standard)
  • Blacklist status across major RBLs
  • Link safety scanning (phishing, malware, redirects)
  • Accessibility compliance (alt text, semantic HTML)
  • Content analysis (word count, readability, image ratio)

Best Practices:

  • Test emails BEFORE sending to large lists
  • Fix high spam scores (aim for < 5.0)
  • Ensure all links are safe and valid
  • Add alt text to images for accessibility
  • Balance text/image ratio (avoid image-only emails)

Performance:

  • Average test time: 2-5 seconds
  • Cached blacklist checks for speed
  • Real-time spam scoring
Security
ApiKeyAuth
Bodyapplication/jsonrequired
fromstring, (email)required

Sender email address

Example:"no-reply@yourdomain.com"
tostring, (email)required

Test recipient (not actually sent)

Example:"test@example.com"
subjectstring, <= 998 charactersrequired

Email subject line

Example:"Weekly Newsletter - March 2026"
htmlstringrequired

HTML email content

Example:"<html><body><h1>Hello!</h1><p>This is a test.</p></body></html>"
textstring

Plain text version (optional)

Example:"Hello! This is a test."
curl -i -X POST \
  https://api.mailerlogic.net/api/v1/test-deliverability \
  -H 'Content-Type: application/json' \
  -H 'X-API-Key: YOUR_API_KEY_HERE' \
  -d '{
    "from": "no-reply@yourdomain.com",
    "to": "test@example.com",
    "subject": "Weekly Newsletter - March 2026",
    "html": "<html><body><h1>Hello!</h1><p>This is a test.</p></body></html>",
    "text": "Hello! This is a test."
  }'

Responses

Deliverability test completed successfully

Bodyapplication/json
successboolean
Example:true
test_idstring, (uuid)

Unique test identifier for tracking

overall_scoreinteger

Overall deliverability score (0-100, higher is better)

Example:85
gradestring

Letter grade based on overall score

Enum:"excellent""good""fair""poor""critical"
Example:"good"
spam_scoreobject

SpamAssassin spam scoring results

blacklist_checkobject

Blacklist status across major RBLs

accessibilityobject

Accessibility compliance check

content_analysisobject

Content quality analysis

recommendationsArray of strings

Overall recommendations to improve deliverability

Example:
[
  "Add alt text to all images",
  "Include an unsubscribe link",
  "Reduce spam score by fixing header issues"
]
tests_remaininginteger

Number of tests remaining this month for your tier

Example:42
tier_limitinteger

Monthly test limit for your tier

Example:50
Response
{
  "success": true,
  "test_id": "22e96a18-23fe-4c06-8ee6-180390ceaded",
  "overall_score": 85,
  "grade": "good",
  "spam_score": {
    "score": 3.2,
    "threshold": 5,
    "is_spam": false,
    "tests_failed": [ … ],
    "recommendations": [ … ]
  },
  "blacklist_check": {
    "listed_count": 0,
    "total_checked": 12,
    "is_clean": true,
    "results": [ … ]
  },
  "link_safety": {
    "total_links": 5,
    "safe_links": 5,
    "suspicious_links": 0,
    "broken_links": 0,
    "issues": [ … ]
  },
  "accessibility": {
    "score": 90,
    "images_with_alt": 3,
    "images_without_alt": 0,
    "has_semantic_html": true,
    "issues": [ … ]
  },
  "content_analysis": {
    "word_count": 250,
    "has_unsubscribe_link": true,
    "text_to_image_ratio": 0.85,
    "has_excessive_links": false,
    "readability_grade": "8th grade"
  },
  "recommendations": [
    "Add alt text to all images",
    "Include an unsubscribe link",
    "Reduce spam score by fixing header issues"
  ],
  "tests_remaining": 42,
  "tier_limit": 50
}