AnchorKite Readability Checker vs Botoi Readability API

AnchorKite Readability Checker is a free browser tool for evaluating pasted English text. It reports Flesch Reading Ease, Flesch-Kincaid Grade Level, Gunning Fog, SMOG, Coleman-Liau, and Automated Readability Index scores. A headline grade estimate averages five grade-level formulas. The page also displays word, sentence, syllable, and letter counts, together with words per sentence and syllables per word. Analysis runs locally, with no network requests, analytics, transmission, storage, or logging of the text according to the page. After loading, the browser tab can continue working offline. Syllable counting uses an approximate heuristic, so irregular spellings and proper names can differ by a syllable. The maker advises treating scores as a sanity check because lists, code, dialogue, headings, abbreviations, and short passages can affect formulas. Guidance covers teachers, writers, workplace writing, general audiences, and specialist writing.

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.