Website Readability analyzes live web pages to score their reading difficulty and educational grade level. It returns Flesch Reading Ease, Flesch-Kincaid grade level, word count, sentence count, and estimated reading time.
Try it — live request, no key required
No key required to try it. Get a key to use it in your app.
{
"status": "ok",
"error": null,
"data": {
"fleschReadingEase": 24.34,
"fleschReadingEaseText": "Very Confusing",
"fleschKincaidGrade": 19.3,
"gunningFog": 19.62,
"colemanLiauIndex": 13.12,
"smogIndex": 14.37,
"automatedReadabilityIndex": 22.6,
"daleChallReadabilityScore": 17,
"daleChallReadabilityScoreText": "average 13th to 15th-grade (college) student",
"wordCount": 634,
"sentenceCount": 29,
"readingTimeMinutes": 3,
"averageGradeLevel": 17.8,
"targetAudience": "post-graduate",
"url": "https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/concepts"
}
}
About the Website Readability API
Ways to call it
One endpoint, many ways in — REST with JSON, XML, YAML and CSV, plus GraphQL and an MCP interface for AI agents.
- JSON
- Default REST response
- XML
- Markup format
- YAML
- Human-readable
- CSV
- Tabular export
- GraphQL
- Query language
- MCP
- For AI agents
Other ways to use Website Readability
Same data, same APIVerve account, same credit balance — one key works on all of them.
What does the Website Readability API do?
How do I authenticate Website Readability API requests?
How much does the Website Readability API cost?
How fast is the Website Readability API?
What response formats does the Website Readability API support?
What HTTP method does the Website Readability API use?
Request parameters — POST /v1/websitereadability
Sent as JSON in the request body. Premium parameters are accepted on every plan but only take effect on plans that include them. Anything not listed here is dropped rather than passed through.
Required
| Parameter | Type | Example | Description |
|---|---|---|---|
urlRequired | string | https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/concepts | The URL of the web page to analyze url |
curl -X POST "https://api.apiverve.com/v1/websitereadability" \
-H "x-api-key: YOUR_API_KEY" \
-H "Content-Type: application/json" \
-d '{"url":"https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/concepts"}'Authentication
Send your key in the x-api-key header. That is the only auth step — no token exchange, and no per-endpoint scope to configure.
| Header | When | Value |
|---|---|---|
x-api-keyRequired | Every request | Your API key. Header names are case-insensitive, so X-API-Key is the same header. |
AuthorizationAlternate | Instead of the above | Bearer <key> — for clients that only expose bearer auth. Resolves to the same account and the same billing. |
content-typeRequired | POST body | application/json |
A 401 means the key is missing, invalid or expired. A 403 means the key is valid but not permitted here — blocked by a key restriction or an IP allow-list. Running out of credits is a 429.
Response — POST /v1/websitereadability
Every APIVerve endpoint returns the same three top-level keys, so one response handler covers your whole integration: status, error and data. Only data changes shape.
{
"status": "ok",
"error": null,
"data": {
"fleschReadingEase": 24.34,
"fleschReadingEaseText": "Very Confusing",
"fleschKincaidGrade": 19.3,
"gunningFog": 19.62,
"colemanLiauIndex": 13.12,
"smogIndex": 14.37,
"automatedReadabilityIndex": 22.6,
"daleChallReadabilityScore": 17,
"daleChallReadabilityScoreText": "average 13th to 15th-grade (college) student",
"wordCount": 634,
"sentenceCount": 29,
"readingTimeMinutes": 3,
"averageGradeLevel": 17.8,
"targetAudience": "post-graduate",
"url": "https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/concepts"
}
}
Response fields
Paths are relative to data. Premium fields are absent rather than zeroed on plans that do not include them, so check for presence instead of comparing to 0.
| Field | Type | Example | Description |
|---|---|---|---|
fleschReadingEase | number | 24.34 | Flesch Reading Ease score (0-100, higher is easier) |
fleschReadingEaseText | string | "Very Confusing" | Descriptive text interpretation of Flesch Reading Ease |
fleschKincaidGrade | number | 19.3 | Flesch-Kincaid Grade Level (US school grade equivalency) |
gunningFogPremium | number | 19.62 | Gunning Fog Index (years of education needed to understand) |
colemanLiauIndexPremium | number | 13.12 | Coleman-Liau Index (US grade level based on character count) |
smogIndexPremium | number | 14.37 | SMOG Index (years of education to understand text) |
automatedReadabilityIndexPremium | number | 22.6 | Automated Readability Index (US grade level estimate) |
daleChallReadabilityScorePremium | number | 17 | Dale-Chall Readability Score (educational level) |
daleChallReadabilityScoreTextPremium | string | "average 13th to 15th-grade (college) student" | Descriptive interpretation of Dale-Chall Readability Score |
wordCount | number | 634 | Number of words in the page's readable text |
sentenceCount | number | 29 | Number of sentences in the page's readable text |
readingTimeMinutes | number | 3 | Estimated reading time in minutes at an average adult reading speed of 238 words per minute |
averageGradeLevelPremium | number | 17.8 | Single averaged US school grade level digested from the grade-based indices (Flesch-Kincaid, Gunning Fog, Coleman-Liau, SMOG, ARI) — the one number that summarizes how much education a reader needs |
targetAudiencePremium | string | "post-graduate" | Reader band mapped from the average grade level: elementary, middle school, high school, college, post-graduate or general public |
url | string | "https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/concepts" | The analyzed URL from the request |
Response headers
Every response carries your balance, so your own code always knows where it stands without polling anything. All four are exposed to browsers through CORS.
| Header | What it carries |
|---|---|
x-api-remaining-credits | Credits left in the current cycle |
x-api-credits-used | Credits spent in the current cycle |
x-api-max-credits | The allowance for the cycle |
x-api-version | Version of the endpoint that answered |
Errors
Read the HTTP status first, then error for the specific reason. The body names the parameter that has to change.
| Status | Meaning | What to do |
|---|---|---|
400 | Input was rejected | Read error; it names the parameter that has to change. |
401 | Key missing or invalid | Check the header name and the key value. |
403 | Key valid, but not permitted here | A key restriction or an IP allow-list — never a bad key. |
429 | Rate limited, or out of credits | Read error to tell them apart, then back off or top up. |
What a call costs — 10 credits per call
Credits are shared across every APIVerve API — one balance, one key, one bill. Failed requests never count against it, so a rejected input costs nothing.
| Plan | Per month | Credits | Website Readability calls | Per 1,000 calls |
|---|---|---|---|---|
| Free | Free | 200 | 20 | Free |
| Starter | $29.99 | 200,000 | 20,000 | $1.50 |
| Pro | $99.99 | 1,000,000 | 100,000 | $1.00 |
| Mega | $299.99 | 4,000,000 | 400,000 | $0.75 |
Calls are what the credits buy at this API's rate — spend them here, on any of the other APIs, or across both. Nothing is reserved per endpoint.
Call it from cURL — POST /v1/websitereadability
No SDK to install — this is a plain HTTPS call to /v1/websitereadability with your key in the x-api-key header. Swap in a real key and it runs as-is.
curl "https://api.apiverve.com/v1/websitereadability" \
-H "x-api-key: YOUR_API_KEY"Resources
Also published for
Only the languages APIVerve ships a client for are listed — the rest call the endpoint directly over HTTPS.
Call it from Node.js — POST /v1/websitereadability
Install the Node.js SDK, then call the Website Readability API with your key. The client wraps the same HTTPS request, so anything it returns is what the endpoint returns.
npm install @apiverve/websitereadabilityconst res = await fetch("https://api.apiverve.com/v1/websitereadability", {
headers: { "x-api-key": "YOUR_API_KEY" },
});
const { data } = await res.json();
console.log(data);Resources
Also published for
Only the languages APIVerve ships a client for are listed — the rest call the endpoint directly over HTTPS.
Call it from Python — POST /v1/websitereadability
Install the Python SDK, then call the Website Readability API with your key. The client wraps the same HTTPS request, so anything it returns is what the endpoint returns.
pip install apiverve-websitereadabilityimport requests
res = requests.get(
"https://api.apiverve.com/v1/websitereadability",
headers={"x-api-key": "YOUR_API_KEY"},
)
print(res.json()["data"])Resources
Also published for
Only the languages APIVerve ships a client for are listed — the rest call the endpoint directly over HTTPS.
Call it from C# / .NET — POST /v1/websitereadability
Install the C# / .NET SDK, then call the Website Readability API with your key. The client wraps the same HTTPS request, so anything it returns is what the endpoint returns.
dotnet add package APIVerve.API.WebsiteReadabilityusing var client = new HttpClient();
client.DefaultRequestHeaders.Add("x-api-key", "YOUR_API_KEY");
var json = await client.GetStringAsync("https://api.apiverve.com/v1/websitereadability");
Console.WriteLine(json);Resources
Also published for
Only the languages APIVerve ships a client for are listed — the rest call the endpoint directly over HTTPS.
Call it from Go — POST /v1/websitereadability
No SDK to install — this is a plain HTTPS call to /v1/websitereadability with your key in the x-api-key header. Swap in a real key and it runs as-is.
req, _ := http.NewRequest("GET", "https://api.apiverve.com/v1/websitereadability", nil)
req.Header.Set("x-api-key", "YOUR_API_KEY")
res, _ := http.DefaultClient.Do(req)
defer res.Body.Close()
body, _ := io.ReadAll(res.Body)
fmt.Println(string(body))Resources
Also published for
Only the languages APIVerve ships a client for are listed — the rest call the endpoint directly over HTTPS.
Call it from PHP — POST /v1/websitereadability
No SDK to install — this is a plain HTTPS call to /v1/websitereadability with your key in the x-api-key header. Swap in a real key and it runs as-is.
$ch = curl_init("https://api.apiverve.com/v1/websitereadability");
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_HTTPHEADER, ["x-api-key: YOUR_API_KEY"]);
$response = curl_exec($ch);
echo $response;Resources
Also published for
Only the languages APIVerve ships a client for are listed — the rest call the endpoint directly over HTTPS.
Call it from Ruby — POST /v1/websitereadability
No SDK to install — this is a plain HTTPS call to /v1/websitereadability with your key in the x-api-key header. Swap in a real key and it runs as-is.
require "net/http"
uri = URI("https://api.apiverve.com/v1/websitereadability")
req = Net::HTTP::Get.new(uri)
req["x-api-key"] = "YOUR_API_KEY"
res = Net::HTTP.start(uri.hostname, uri.port, use_ssl: true) { |h| h.request(req) }
puts res.bodyResources
Also published for
Only the languages APIVerve ships a client for are listed — the rest call the endpoint directly over HTTPS.
Zero-code embed — one snippet, no backend
Drop an interactive Website Readability form onto any page. The widget calls the API for you, so no key ever appears in your markup and there is nothing to deploy.
Changelog — Website Readability API
Every change to this endpoint, newest first. Breaking changes ship as a new version and the previous one keeps serving — response fields are added, never removed or retyped in place, so an integration written against v1 keeps working.
Entries are picked up from dated catalog snapshots, so the first one appears after the next snapshot that moves something. A period where nothing changed produces no entry — silence is a valid changelog for the Website Readability API.
Text Processing
- Acronym Expander
- Anagram Detector
- Antonym Finder
- Cron Expression Parser
- Data Masking
- Did You Mean
- Emoji Decorator
- Gibberish Detector
- Grammar Check
- ISBN Validator
- JSON Schema Validator
- Keyword Extractor
- Leet Speak
- Levenshtein Distance
- Line Sorter
- Markdown Link Extractor
- Palindrome Checker
- Parts Of Speech
- Phonetic Encoder
- Pig Latin
- Profanity Filter
- Reading Time Calculator
- Regex Tester
- Remove Punctuation
- Reverse Text
- Rhyming Words
- Slugify
- Spell Checker
- Syllable Counter
- Tax ID Validator
- Tense Converter
- Text Language
- Text Lemmatizer
- Text Readability Score
- Text Similarity
- Text Styler
- Text Summarizer
- Text to Emoji
- Title Case Converter
- Translator
- Vowel Counter
- Website Readability
- Word Lexicon Analyzer
- Word Opposites
- Word Pronunciation
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