APIs › Kurdish, Arabic & Text Utilities › Readability Metrics

Readability Metrics

Computes Flesch Reading Ease, Flesch-Kincaid grade, Gunning Fog, SMOG, Coleman-Liau and ARI with the underlying syllable and sentence counts.

POST /v1/text/readability $0.005 per call

Specification

Endpoint

POST /v1/text/readability

Price

$0.005 per call · tier basic_data

Payment

x402 on X Layer (chain 196) · settled in USDG or USDT0 · schemes exact, aggr_deferred

Data source

Deterministic local computation on caller-supplied text

Timeout

15 seconds

Max request

1 MB

Version

1.0.0

Calling it

The first call returns a 402 with the payment challenge. Retry with a signed authorisation in the X-PAYMENT header — see the payment guide for the exact shape.

curl -i -X POST "https://api.dana-edu.pp.ua/v1/text/readability" \
  -H "content-type: application/json" \
  -d '{ ... }'

Response

Real output, captured by running this endpoint at build time — not written by hand. Volatile fields such as timestamps are elided. Captured 2026-07-30.

{
  "counts": {
    "sentences": 2,
    "words": 10,
    "syllables": 21,
    "complex_words": 2,
    "characters": 56,
    "words_per_sentence": 5,
    "syllables_per_word": 2.1
  },
  "metrics": {
    "flesch_reading_ease": 24.1,
    "flesch_kincaid_grade": 11.1,
    "gunning_fog": 10,
    "smog": null,
    "coleman_liau": 11.2,
    "automated_readability_index": 7.4
  },
  "interpretation": {
    "flesch_reading_ease": "very difficult (graduate level)"
  }
}

Every response is wrapped in the same envelope: data plus warnings, sources, confidence, informational_only and a measured processing_ms. See the envelope reference.

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