AI Humanizer API Documentation — REST API Reference

Quickstart

Get up and running in under a minute.

Get your API key

Make your first request

curl -X POST https://api.writehuman.ai/v1/humanize \
  -H "Authorization: Bearer wh_live_your_api_key_here" \
  -H "Content-Type: application/json" \
  -d '{"text": "Artificial intelligence has revolutionized the way we approach content creation and digital communication."}'

See the response

Standard plans return a single result. Premium plans return 3 variations with human-likeness scores.

{
  "results": [
    "AI has changed how we create content and communicate online."
  ],
  "input_words": 14,
  "words_remaining": {
    "included": 124986,
    "topup": 0
  }
}

Authentication

All API requests require a Bearer token in the Authorization header. You can create and manage API keys from your dashboard.

Authorization: Bearer wh_live_your_api_key_here

Keys use the prefix wh_live_ followed by a unique token. Keep your keys secret — treat them like passwords. You can create up to 5 keys and revoke any key at any time.

Plans & Limits

Choose a plan that fits your usage. All plans include monthly word allowances that reset each billing cycle.

	Standard	Premium
Monthly words	125,000	400,000
Max words per request	2,000	4,000
Output variations	1	3
Human-likeness scores
Rate limit	10 req/min	60 req/min
Concurrency	2	5

Standard

Monthly words125,000

Max words per request2,000

Output variations1

Human-likeness scores

Rate limit10 req/min

Concurrency2

Premium

Monthly words400,000

Max words per request4,000

Output variations3

Human-likeness scores

Rate limit60 req/min

Concurrency5

Premium plans automatically return 3 output variations per request with human-likeness scores. Standard plans return a single result without scores. Usage is tracked by input text word count. Words are deducted from your subscription first, then any top-up credits. Top-up packs (125,000 words each) never expire.

Endpoint Reference

POST/v1/humanize

https://api.writehuman.ai/v1/humanize

Rewrite AI-generated text to sound naturally human. Deducts input words from your balance. Usage is tracked by input text word count. Words are deducted from your monthly subscription allowance first, then from any purchased top-up credits.

Request Body — application/json

textrequired

string

The text to humanize.

>= 30 characters, <= 100,000 characters

toneoptional

string

Optional writing tone. Omit for default style.

Allowed: professional, academic, blog, casual, creative, scientific, technical

languageoptional

string | null

Target language (e.g. English, Spanish, Chinese (Mandarin)). Auto-detected if omitted.

200Text humanized successfully

Response Body — application/json

results

string[]

Humanized text variations, sorted by score (best first).

scores

(number | null)[]

Human-likeness score for each result (0–1, higher = more human).

Premium plans only. Omitted for Standard plans.

input_words

integer

Number of words billed for this request.

words_remaining

object

Your remaining word balance after this request.

Fields: included (integer), topup (integer), total (integer)

Error Responses

401

Missing or invalid API key.

{ "error": "Invalid API key" }

403

No active subscription.

{ "error": "No active subscription" }

422

Invalid input, over word limit, or content blocked by moderation.

Word limit exceeded

{ "error": "Input exceeds per-request limit of 2000 words for your plan. Received ~2500 words." }

Content moderation

{ "error": "Content blocked: sexual" }

429

Insufficient balance, rate limit, or concurrency limit exceeded.

Insufficient balance

{
  "error": "Insufficient word balance",
  "words_remaining": {
    "included": 12,
    "topup": 0
  }
}

Rate limit

{ "error": "Rate limit exceeded (10 requests/minute)" }

Concurrency limit

{ "error": "Too many concurrent requests (max 2)" }

500

Processing failure.

{ "error": "Processing failed" }

Code Examples

Full working examples in popular languages. Replace the API key with your own to get started.

curl -X POST https://api.writehuman.ai/v1/humanize \
  -H "Authorization: Bearer wh_live_your_api_key_here" \
  -H "Content-Type: application/json" \
  -d '{"text": "Artificial intelligence has revolutionized the way we approach content creation and digital communication."}'

Response

The response format depends on your plan.

{
  "results": [
    "AI has changed how we create content and communicate online."
  ],
  "input_words": 14,
  "words_remaining": {
    "included": 124986,
    "topup": 0
  }
}

Supported Languages

WriteHuman supports 40+ languages. Pass the language name as the language parameter, or omit it for automatic detection.

EnglishEnglish (British)Chinese (Mandarin)Chinese (Taiwanese)FrenchSpanishVietnamesePortugueseJapaneseUkrainianSwedishGermanRussianItalianArabicHindiBengaliKoreanTurkishDutchPolishThaiIndonesianMalayPersianHebrewGreekCzechDanishFinnishNorwegianRomanianHungarianSlovakBulgarianCroatianSerbianSlovenianLithuanianLatvianEstonianUrduSwahiliTagalogAfrikaans

Common Use Cases

Content Marketing

Generate blog posts, product descriptions, and ad copy with AI that reads indistinguishable from human writing.

SEO Agencies

Produce high-volume content that passes AI detection checks before publication.

SaaS Products

AI writing features where the final output needs to be indistinguishable from human writing.

Enterprise Teams

Process internal communications, reports, and documentation generated by large language models.

Support

Contact Support Terms of Service

By using the WriteHuman API you agree to our Terms of Service.