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§01API

API Documentation.
Build on HumanGPT.

Integrate AI text humanization into your content pipeline. REST API with JSON responses. Same humanization engine as the web tool. Pro plan required.

§02Overview

Quick start.

The HumanGPT API lets you programmatically humanize AI-generated text. It's the same engine that powers the web tool: same Gemini-based pipeline, same modes, same bypass rates. The only difference is you're calling it from code instead of a browser.

Base URL: https://api.humangpt.io/v1

Authentication: Include your API key in the Authorization header as a Bearer token.

§03Humanize

POST /humanize

Rewrites AI-generated text to bypass AI detectors. Returns the humanized text with metadata.

Request
POST https://api.humangpt.io/v1/humanize
Authorization: Bearer YOUR_API_KEY
Content-Type: application/json

{
  "text": "Your AI-generated text here...",
  "mode": "medium",
  "purpose": "academic",
  "reading": "university",
  "enhanced": false,
  "freeze": ["specific terms", "to preserve"],
  "language": "auto"
}
Parameters
text required — The AI text to humanize. Max 5,000 words (Pro), 1,500 words (Free).
mode optional — Humanization intensity: "light", "medium" (default), or "heavy".
purpose optional — Writing context: "general" (default), "academic", "essay", "article", "marketing", "legal", "story", "report", "business".
reading optional — Target reading level: "highschool", "university" (default), "doctorate", "journalist".
enhanced optional — Boolean. Pushes humanization one level harder. Default false.
freeze optional — Array of strings to preserve unchanged through the rewrite.
language optional — ISO language code or "auto" (default). Supports 30+ languages.
Response (200 OK)
{
  "output": "The humanized text...",
  "mode": "medium",
  "purpose": "academic",
  "reading": "university",
  "enhanced": false,
  "input_words": 247,
  "output_words": 252,
  "quota_remaining": 49753
}
§04Detect

POST /check

Checks text against all 7 AI detectors. Returns per-detector scores and perplexity/burstiness metrics.

Request
POST https://api.humangpt.io/v1/check
Authorization: Bearer YOUR_API_KEY
Content-Type: application/json

{
  "text": "Text to check for AI detection..."
}
Response (200 OK)
{
  "overall_ai_probability": 14,
  "verdict": "human",
  "detectors": {
    "gptzero": { "score": 12, "verdict": "human" },
    "turnitin": { "score": 8, "verdict": "human" },
    "originality": { "score": 16, "verdict": "human" },
    "copyleaks": { "score": 10, "verdict": "human" },
    "zerogpt": { "score": 6, "verdict": "human" },
    "sapling": { "score": 14, "verdict": "human" },
    "winston": { "score": 12, "verdict": "human" }
  },
  "metrics": {
    "perplexity": 72,
    "burstiness": 24
  }
}
§05Examples

Code examples.

Python
import requests

response = requests.post(
    "https://api.humangpt.io/v1/humanize",
    headers={"Authorization": "Bearer YOUR_API_KEY"},
    json={
        "text": "AI-generated text to humanize...",
        "mode": "medium",
        "purpose": "academic"
    }
)

result = response.json()
print(result["output"])
JavaScript / Node.js
const response = await fetch(
  "https://api.humangpt.io/v1/humanize",
  {
    method: "POST",
    headers: {
      "Authorization": "Bearer YOUR_API_KEY",
      "Content-Type": "application/json"
    },
    body: JSON.stringify({
      text: "AI-generated text to humanize...",
      mode: "medium",
      purpose: "academic"
    })
  }
);

const { output } = await response.json();
console.log(output);
cURL
curl -X POST https://api.humangpt.io/v1/humanize \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"text":"AI text here...","mode":"medium"}'
§06Errors

Error codes.

CodeMeaningFix
400Bad requestCheck your JSON payload. Text field is required.
401UnauthorizedCheck your API key. Must be a valid Pro or Lifetime key.
429Rate limitedToo many requests. Wait and retry. Max 60 req/min.
402Quota exceededMonthly or lifetime word limit reached. Upgrade or wait for reset.
500Server errorRetry after a few seconds. If persistent, contact support.
§07API FAQ

API Questions.
Straight answers.

  • Yes. API access is included with Pro ($10/month, 50K words) and Lifetime ($199, 1M words) plans. The free tier is web-only.

  • Pro users can make up to 60 requests per minute. Each request can contain up to 5,000 words of input text. Rate limits are per API key.

  • Identical. The API uses the same Gemini-powered humanization pipeline. Same modes, same purposes, same bypass rates. The web tool is just a frontend for the same API.

  • Yes. Send multiple requests sequentially or in parallel (within rate limits). Each request is independent. For very large batches (100K+ words), contact us for volume pricing.

  • All 30+ languages supported by the web tool. Set the language parameter or let auto-detection handle it. Each language uses native rewriting patterns.

  • After subscribing to Pro or Lifetime, your API key is available in your dashboard. One key per account. Keys can be regenerated if compromised.

★ bottom line

Same engine. Same quality. Programmable. Build AI humanization into your content pipeline with two API calls.

Get API access