ApyHub Readability Scores Documents API vs ATOS Analyzer

ApyHub Readability Scores Documents API scores documents and publicly accessible web pages, returning a readability score, reading level, and text statistics. File requests accept PDF, DOC, or DOCX uploads up to 100 MB. English checks use the Flesch Reading Ease formula by default, while German uses the Wiener Sachtextformel. Results can include word, sentence, character, and paragraph counts, average lengths, and estimated reading and speaking times. The score includes a grade class, a plain-language label, and an indication of whether a standard readability threshold is met. ApyHub lists uses such as reviewing contracts, policies, manuals, help pages, websites, reports, and proposals; AI agents can also access the API through ApyHub MCP for content reviews. The product page offers five API calls a day free without a card. Starter is free and includes 3,000 atoms per month; Pro costs $16 a month and Pro+ $42 a month. Requests can return a 429 rate_limited error when the plan's per-second limit is exceeded.

ATOS Analyzer is a free web tool for estimating the readability level of text and books in English or Spanish. Users can enter a passage, analyze an entire book, or submit a sample with an estimated word count. Text can be typed or uploaded as a .txt, .docx, or .epub file, with uploads limited to 10 MB. The suggested passage length is 150 to 25,000 characters. Results include an ATOS level, grade-level equivalent, word count, AR Points, average word length, average sentence length, and language. ATOS estimates complexity on a grade-level scale using sentence length, word length, and word difficulty; its measure also accounts for book length. For a sampled book, Renaissance recommends three passages of about 150 words from different parts and an estimated total word count. Scanned documents need OCR to become recognized text before submission; changing a file extension does not convert them. The page includes a CCSS/ATOS grade-band chart for grades 1 through 12. Renaissance presents the measure as guidance for matching students with appropriately leveled reading material.