Readability

Analyze text readability across multiple scoring systems — Flesch-Kincaid, Gunning Fog, Coleman-Liau, SMOG, and ARI — plus reading time and text statistics.

POST /api/readability

Parameters

Field	Type	Required	Description
text	string	Yes	Text to analyze

Response

Field	Type	Description
flesch_kincaid_grade	number	Flesch-Kincaid grade level
flesch_reading_ease	number	Flesch reading ease score (0–100)
gunning_fog	number	Gunning Fog index
coleman_liau	number	Coleman-Liau index
smog	number	SMOG index
ari	number	Automated Readability Index
grade_level	string	Consensus grade level
reading_time_seconds	number	Estimated reading time in seconds
words	integer	Word count
sentences	integer	Sentence count
syllables	integer	Syllable count
characters	integer	Character count
avg_words_per_sentence	number	Average words per sentence
avg_syllables_per_word	number	Average syllables per word

Example

curl -X POST https://morso.dev/api/readability \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"text": "The quick brown fox jumps over the lazy dog. Simple sentences are easy to read. Complex vocabulary and lengthy subordinate clauses increase difficulty."}'

{
  "flesch_kincaid_grade": 8.2,
  "flesch_reading_ease": 62.5,
  "gunning_fog": 10.1,
  "coleman_liau": 11.3,
  "smog": 9.8,
  "ari": 8.7,
  "grade_level": "8th-9th grade",
  "reading_time_seconds": 6.0,
  "words": 25,
  "sentences": 3,
  "syllables": 38,
  "characters": 152,
  "avg_words_per_sentence": 8.3,
  "avg_syllables_per_word": 1.52
}