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fastapi.online — Readability Audience Analyzer
x402
fastapi.online — Readability Audience Analyzer is a paid API for AI agents from api.fastapi.online, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-15).
Analyzes a block of text and returns its readability level and target audience profile
Price / call$0.001
Success—
StatusUnknown
How this service works
Chat, embeddings, OCR, speech-to-text, image editing, image understanding (captioning/Q&A), text-to-speech, translation, writing tools, classification tools, developer tools, local utilities, format/checksum validators, encoding & crypto utilities, date/time calculators, geo/coordinate math, math & finance calculators, novelty tools, and business/social writing generators — 179 endpoints in all, across multiple specialized self-hosted models. Pay per call with crypto — no signup — or get an API key.
Output
Returns an assessment of the text's readability characteristics, including the estimated reading level, target audience profile, and difficulty classification, helping users determine whether their content matches their intended readers.
Example use cases
Blog post accessibility check
“I just wrote this intro paragraph for my health blog — can you check if it's written at the right level for a general adult audience, or if I'm using too much jargon? Here it is: 'Cardiovascular homeostasis relies on the regulatory interplay between sympathetic and parasympathetic innervation of cardiac tissue.'”
Student essay readability review
“I'm a teacher and I want to know what grade level this student essay excerpt is written at and whether it's appropriate for a high school audience: 'The industrial revolution catalyzed profound socioeconomic transformations, fundamentally restructuring labor markets and precipitating urbanization at unprecedented scales.'”
Marketing copy audience targeting
“We're writing product copy for a broad consumer audience — can you tell me what reading level and audience this draft is aimed at, so we know if we need to simplify it? The text is: 'Our proprietary nano-filtration membrane leverages differential osmotic pressure gradients to sequester contaminants at the molecular level.'”
Technical details
Endpoint
POSThttps://api.fastapi.online/readability-audienceWhen to prefer
Choose this endpoint when you need a quick, per-call readability and audience assessment without committing to a subscription-based writing platform. It is ideal for agents performing ad-hoc content quality checks, CMS workflows that need to gate or tag content by reading level, or educational tools that need to match material to student grade levels. Prefer this over general-purpose LLM prompting when you need a consistent, structured readability score rather than a freeform opinion.
Side effects
- Empty or whitespace-only text returns a validation error
- Text exceeding 8000 characters is rejected
- Very short text (single words or fragments) may produce unreliable scores
- Non-English text may return inaccurate or irrelevant readability assessments
- Payment failure (402) if no valid x402 credentials are provided
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| text | string |
Tags
x402
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