Botoi Readability API vs Readability Formulas

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.

Readability Formulas offers tools to score English text and estimate the grade level and age of readers likely to understand it. Its Readability Scoring System includes formulas such as Flesch Reading Ease, Flesch-Kincaid, Gunning Fog, SMOG, Dale-Chall, Spache, FORCAST, Fry and Raygor. Text can be pasted or supplied as .txt, .docx, .rtf, .html or .pdf files. Text Statistics reports measures including syllable count, average sentence length, abbreviations, proper nouns and passive voice. The beta Robert Gunning Editor helps locate difficult words and wordiness, with editing tools for phrases, nominalizations, fuzzy words and weak verbs. Batch Processing, also in beta, scores multiple texts with one or more formulas. A Chrome and Microsoft Edge extension can score highlighted web text, open the editor and show word statistics. The privacy policy says processing runs through local browser scripts and submitted text is not stored on a server or accessible to the site. The Synonym Finder connects to Datamuse and may transmit one word at a time.