Botoi Readability API vs Health Literacy Advisor

Botoi Readability API analyzes English text and returns Flesch-Kincaid Grade, Flesch Reading Ease, Gunning Fog, and underlying counts. A request sends a required text string to POST /v1/text/readability and receives JSON. Flesch Reading Ease scores run from 0 to 100, with higher values indicating easier reading; Gunning Fog estimates the years of formal education needed. The formulas and syllable heuristics are calibrated for English, so grade mapping is not meaningful for other languages. Botoi recommends sending at least 100 words because short samples can produce unstable scores. Suggested uses include enforcing plain-language standards, reviewing legal or medical drafts, refining blog posts for SEO, and comparing writing across authors. Examples are provided in cURL, JavaScript, TypeScript, Python, and Go. The Free plan is free and lists 1,000 requests per day and 10 per minute; the endpoint page separately states five requests per minute for its free tier. Starter costs $9 a month. Requests above a per-minute or daily cap receive HTTP 429, and daily limits reset at midnight UTC.

Health Literacy Advisor (HLA) assesses and improves document readability using plain-language principles. The desktop edition works inside Microsoft Word, highlighting complicated words, words with three or more syllables, and long sentences. It includes nine readability indices, including Fry-Based, Precise SMOG, Gunning-Fog, ARI, Flesch-Kincaid, Dale-Chall, FORCAST, and Coleman-Liau. An interactive Search and Replace feature offers plain-language alternatives and descriptions for more than 12,000 difficult words, phrases, and medical jargon. ReadEasy Document Assessment pairs readability data with a self-assessment covering readability, content, design, and cultural appropriateness. HLA Online assesses and improves documents in a browser, and saves documents with their scores and details. It works on desktop computers, laptops, tablets, and mobile devices running Windows, Macintosh, Android, or iOS. Its private remote server is described as HIPAA compliant. Desktop and Online licenses run for 365 days from activation and are assigned to one individual; they may not be shared or transferred without written permission. English licenses cost $499 a year, and English and Spanish licenses cost $599 a year.