No. 16 of 25 ·AI Readability Checkers

Oanor Readability API

API · paid plans from €6.80/mo

Freedom report

Two barsScore 6.3

Free tierA free tier is on its own pricing page
Open codeNo open-source code on record
Runs widely0 of 6 device platforms
DocumentedPlans, terms and facts published

Oanor Readability API is ranked #16 of 25 in AI readability checkers on Freedom251. It runs on API. There is a free plan. Paid plans start at €6.80/mo.

Oanor Readability API plans and pricing

All plans

Free Free Free 2,340 calls/month · 2 requests/second · hard cap (429 above quota, no overage) · 6 formulas + counts · no credit card oanor.com · 8 Oct 2026

Starter €6.80/mo €6.80 /month 46,500 calls/month · 8 requests/second · hard cap (429 above quota, no overage) · reading time + syllables · email support oanor.com · 8 Oct 2026

Pro €21.50/mo €21.50 /month 238,000 calls/month · 20 requests/second · hard cap (429 above quota, no overage) · editorial & SEO pipelines · priority support oanor.com · 8 Oct 2026

Mega €56.80/mo €56.80 /month 875,000 calls/month · 50 requests/second · hard cap (429 above quota, no overage) · content-platform scale · dedicated SLA oanor.com · 8 Oct 2026

Compared on AI readability checkers

Free plan: Yes
Readability scores: 6 scores
Grade-level analysis: Yes
Input formats: api

Best Oanor Readability API alternatives

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The record

Purpose: The API scores text with six readability formulas: Flesch Reading Ease, Flesch-Kincaid Grade, Gunning Fog, SMOG, Coleman-Liau and Automated Readability Index.
Returned data: Analysis returns the six scores, underlying text counts, an averaged grade level, estimated reading time and a plain-English reading-ease interpretation.
Syllable endpoint: A second endpoint counts syllables for a word or for every word in a phrase.
Processing: The product page says computation is local, with no network calls, and describes results as fast and deterministic.
Use cases: The API is described for content and copywriting tools, SEO and editorial workflows, education, accessibility checks and UX-writing review.
Endpoints: The page lists GET /v1/analyze, GET /v1/syllables and GET /v1/meta.
Integration: The page provides curl, JavaScript, PHP and Python request examples; clients authenticate with an x-oanor-key header.
Test access: The browser playground offers 10 free test calls per day.
Quota behavior: Plans use hard caps that return HTTP 429 above quota, with no overage charge; the page says plans are billed monthly and can be canceled anytime.
Security and privacy: The product FAQ says requests pass through an EU-based gateway, the upstream API key stays on the server, and no personal data is shared with the upstream provider beyond the request sent.
Support: The page offers private one-to-one support tickets, and plan descriptions include email support for Starter, priority support for Pro and a dedicated SLA for Mega.
Maker: The imprint identifies oanor.com as a service of Baduno GmbH, located in Frankfurt am Main, Germany.
Price from: €6.80/mo

Where it ranks on Freedom251

Best AI Readability Checkers in 2026#16 of 25

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Sources

oanor.com/api/readability-api· checked 8 Oct 2026
oanor.com/imprint· checked 8 Oct 2026