Readability scores (Flesch) API

Compute readability scores for text: Flesch Reading Ease, Flesch-Kincaid grade level, and a plain-English reading level. Answers 'how readable is this', 'what reading grade level', 'is this text too hard'.

Price$0.01per request

MethodPOST

Route/v1/text/readability

StatusLive

MIME typeapplication/json

Rate limit120/minute

CacheNo cache

textreadabilityfleschgrade-levelreading-easenlp

API URLhttps://x402.hexl.dev/v1/text/readability

Integration docs

Example request

{
  "text": "The cat sat on the mat. It was a sunny day."
}

Example response

{
  "words": 11,
  "sentences": 2,
  "syllables": 12,
  "fleschReadingEase": 100,
  "fleschKincaidGrade": 0.5,
  "readingLevel": "very easy (5th grade)"
}

Input schema

{
  "type": "object",
  "required": [
    "text"
  ],
  "properties": {
    "text": {
      "type": "string"
    }
  }
}

Output schema

{
  "type": "object",
  "additionalProperties": true
}