Writer & Humanizer

curl --request POST \
  --url https://stealthgpt.ai/api/stealthify \
  --header 'Content-Type: application/json' \
  --header 'api-token: <api-token>' \
  --data '
{
  "prompt": "<string>",
  "rephrase": true,
  "tone": "<string>",
  "writingMode": "<string>",
  "mode": "<string>",
  "qualityMode": "<string>",
  "model": "<string>",
  "business": true,
  "isMultilingual": true,
  "detector": "<string>",
  "outputFormat": "<string>"
}
'

import requests

url = "https://stealthgpt.ai/api/stealthify"

payload = {
    "prompt": "<string>",
    "rephrase": True,
    "tone": "<string>",
    "writingMode": "<string>",
    "mode": "<string>",
    "qualityMode": "<string>",
    "model": "<string>",
    "business": True,
    "isMultilingual": True,
    "detector": "<string>",
    "outputFormat": "<string>"
}
headers = {
    "api-token": "<api-token>",
    "Content-Type": "application/json"
}

response = requests.post(url, json=payload, headers=headers)

print(response.text)

const options = {
  method: 'POST',
  headers: {'api-token': '<api-token>', 'Content-Type': 'application/json'},
  body: JSON.stringify({
    prompt: '<string>',
    rephrase: true,
    tone: '<string>',
    writingMode: '<string>',
    mode: '<string>',
    qualityMode: '<string>',
    model: '<string>',
    business: true,
    isMultilingual: true,
    detector: '<string>',
    outputFormat: '<string>'
  })
};

fetch('https://stealthgpt.ai/api/stealthify', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://stealthgpt.ai/api/stealthify",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "POST",
  CURLOPT_POSTFIELDS => json_encode([
    'prompt' => '<string>',
    'rephrase' => true,
    'tone' => '<string>',
    'writingMode' => '<string>',
    'mode' => '<string>',
    'qualityMode' => '<string>',
    'model' => '<string>',
    'business' => true,
    'isMultilingual' => true,
    'detector' => '<string>',
    'outputFormat' => '<string>'
  ]),
  CURLOPT_HTTPHEADER => [
    "Content-Type: application/json",
    "api-token: <api-token>"
  ],
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}

package main

import (
	"fmt"
	"strings"
	"net/http"
	"io"
)

func main() {

	url := "https://stealthgpt.ai/api/stealthify"

	payload := strings.NewReader("{\n  \"prompt\": \"<string>\",\n  \"rephrase\": true,\n  \"tone\": \"<string>\",\n  \"writingMode\": \"<string>\",\n  \"mode\": \"<string>\",\n  \"qualityMode\": \"<string>\",\n  \"model\": \"<string>\",\n  \"business\": true,\n  \"isMultilingual\": true,\n  \"detector\": \"<string>\",\n  \"outputFormat\": \"<string>\"\n}")

	req, _ := http.NewRequest("POST", url, payload)

	req.Header.Add("api-token", "<api-token>")
	req.Header.Add("Content-Type", "application/json")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := io.ReadAll(res.Body)

	fmt.Println(string(body))

}

HttpResponse<String> response = Unirest.post("https://stealthgpt.ai/api/stealthify")
  .header("api-token", "<api-token>")
  .header("Content-Type", "application/json")
  .body("{\n  \"prompt\": \"<string>\",\n  \"rephrase\": true,\n  \"tone\": \"<string>\",\n  \"writingMode\": \"<string>\",\n  \"mode\": \"<string>\",\n  \"qualityMode\": \"<string>\",\n  \"model\": \"<string>\",\n  \"business\": true,\n  \"isMultilingual\": true,\n  \"detector\": \"<string>\",\n  \"outputFormat\": \"<string>\"\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://stealthgpt.ai/api/stealthify")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Post.new(url)
request["api-token"] = '<api-token>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"prompt\": \"<string>\",\n  \"rephrase\": true,\n  \"tone\": \"<string>\",\n  \"writingMode\": \"<string>\",\n  \"mode\": \"<string>\",\n  \"qualityMode\": \"<string>\",\n  \"model\": \"<string>\",\n  \"business\": true,\n  \"isMultilingual\": true,\n  \"detector\": \"<string>\",\n  \"outputFormat\": \"<string>\"\n}"

response = http.request(request)
puts response.read_body

{
  "result": "<string>",
  "howLikelyToBeDetected": 123,
  "remainingCredits": 123,
  "wordsSpent": 123,
  "billingMode": "<string>",
  "meteredChargedCredits": 123,
  "tokensSpent": 123,
  "totalTokensSpent": 123,
  "systemTokensSpent": 123
}

POST

api

stealthify

Writer & Humanizer

curl --request POST \
  --url https://stealthgpt.ai/api/stealthify \
  --header 'Content-Type: application/json' \
  --header 'api-token: <api-token>' \
  --data '
{
  "prompt": "<string>",
  "rephrase": true,
  "tone": "<string>",
  "writingMode": "<string>",
  "mode": "<string>",
  "qualityMode": "<string>",
  "model": "<string>",
  "business": true,
  "isMultilingual": true,
  "detector": "<string>",
  "outputFormat": "<string>"
}
'

import requests

url = "https://stealthgpt.ai/api/stealthify"

payload = {
    "prompt": "<string>",
    "rephrase": True,
    "tone": "<string>",
    "writingMode": "<string>",
    "mode": "<string>",
    "qualityMode": "<string>",
    "model": "<string>",
    "business": True,
    "isMultilingual": True,
    "detector": "<string>",
    "outputFormat": "<string>"
}
headers = {
    "api-token": "<api-token>",
    "Content-Type": "application/json"
}

response = requests.post(url, json=payload, headers=headers)

print(response.text)

const options = {
  method: 'POST',
  headers: {'api-token': '<api-token>', 'Content-Type': 'application/json'},
  body: JSON.stringify({
    prompt: '<string>',
    rephrase: true,
    tone: '<string>',
    writingMode: '<string>',
    mode: '<string>',
    qualityMode: '<string>',
    model: '<string>',
    business: true,
    isMultilingual: true,
    detector: '<string>',
    outputFormat: '<string>'
  })
};

fetch('https://stealthgpt.ai/api/stealthify', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://stealthgpt.ai/api/stealthify",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "POST",
  CURLOPT_POSTFIELDS => json_encode([
    'prompt' => '<string>',
    'rephrase' => true,
    'tone' => '<string>',
    'writingMode' => '<string>',
    'mode' => '<string>',
    'qualityMode' => '<string>',
    'model' => '<string>',
    'business' => true,
    'isMultilingual' => true,
    'detector' => '<string>',
    'outputFormat' => '<string>'
  ]),
  CURLOPT_HTTPHEADER => [
    "Content-Type: application/json",
    "api-token: <api-token>"
  ],
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}

package main

import (
	"fmt"
	"strings"
	"net/http"
	"io"
)

func main() {

	url := "https://stealthgpt.ai/api/stealthify"

	payload := strings.NewReader("{\n  \"prompt\": \"<string>\",\n  \"rephrase\": true,\n  \"tone\": \"<string>\",\n  \"writingMode\": \"<string>\",\n  \"mode\": \"<string>\",\n  \"qualityMode\": \"<string>\",\n  \"model\": \"<string>\",\n  \"business\": true,\n  \"isMultilingual\": true,\n  \"detector\": \"<string>\",\n  \"outputFormat\": \"<string>\"\n}")

	req, _ := http.NewRequest("POST", url, payload)

	req.Header.Add("api-token", "<api-token>")
	req.Header.Add("Content-Type", "application/json")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := io.ReadAll(res.Body)

	fmt.Println(string(body))

}

HttpResponse<String> response = Unirest.post("https://stealthgpt.ai/api/stealthify")
  .header("api-token", "<api-token>")
  .header("Content-Type", "application/json")
  .body("{\n  \"prompt\": \"<string>\",\n  \"rephrase\": true,\n  \"tone\": \"<string>\",\n  \"writingMode\": \"<string>\",\n  \"mode\": \"<string>\",\n  \"qualityMode\": \"<string>\",\n  \"model\": \"<string>\",\n  \"business\": true,\n  \"isMultilingual\": true,\n  \"detector\": \"<string>\",\n  \"outputFormat\": \"<string>\"\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://stealthgpt.ai/api/stealthify")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Post.new(url)
request["api-token"] = '<api-token>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"prompt\": \"<string>\",\n  \"rephrase\": true,\n  \"tone\": \"<string>\",\n  \"writingMode\": \"<string>\",\n  \"mode\": \"<string>\",\n  \"qualityMode\": \"<string>\",\n  \"model\": \"<string>\",\n  \"business\": true,\n  \"isMultilingual\": true,\n  \"detector\": \"<string>\",\n  \"outputFormat\": \"<string>\"\n}"

response = http.request(request)
puts response.read_body

{
  "result": "<string>",
  "howLikelyToBeDetected": 123,
  "remainingCredits": 123,
  "wordsSpent": 123,
  "billingMode": "<string>",
  "meteredChargedCredits": 123,
  "tokensSpent": 123,
  "totalTokensSpent": 123,
  "systemTokensSpent": 123
}

The /api/stealthify endpoint is the core of the StealthGPT API, allowing you to generate new content or rephrase existing text to be undetectable by AI detection tools.

For integrations that cannot keep a request open while humanization runs, use the async POST /api/stealthify/runs flow. This synchronous endpoint remains unchanged for existing API clients.

Request Parameters

string

required

Your unique API authentication token. You can find this in your StealthGPT dashboard under the API Key tab.

string

required

When rephrase is false, the topic or instructions for content generation. When rephrase is true, the existing text to humanize — send only that source text, with no instruction wrappers. Maximum 3,000 words per request.

boolean

required

Set to true to rephrase the provided prompt text, or false to generate new content based on the prompt

Humanize / rephrase input: when rephrase is true, put only the source text in prompt. Do not add instructions such as “Humanize the following text”, “Rewrite this to sound more human”, or “Make this undetectable”. Those prefixes confuse the model and hurt output quality. Control style with API parameters (tone, model, qualityMode, etc.) instead. Instruction-style prompts are for generation (rephrase: false) only.

string

Controls the style and complexity of generated content when writingMode is essay (ignored in default mode and when rephrase is true)

Show Available tone options

default

Ideal for casual writing. Easy to read and understand, suitable for general purposes.

Mimics the style of high school level writing. May contain grammatical errors. Scores high on Flesch-Kincaid Readability.

Semi-complex style typical of college-level writing. May include minor grammatical errors. Moderate Flesch-Kincaid Readability score.

Complex, sophisticated style. No grammatical errors. Low Flesch-Kincaid Readability score, ideal for academic writing.

string

default:"essay"

Controls how content is generated when rephrase is false. Has no effect when rephrase is true.

Show Available writingMode options

default

Structures the output as an academic essay. Use with tone to set education level (Standard, HighSchool, College, PhD).

Follows the user’s prompt as written. Does not force essay structure — suitable for emails, lists, product copy, summaries, or any other format you specify.

string

Indicates the detail level of the response

Show Available mode options

Maximum detail and elaboration in the response

Balanced level of detail

Concise response with minimal detail

string

default:"quality"

Controls rewrite quality vs speed.

Show Available qualityMode options

Default. Runs our quality checks/repairs for better reliability and lower detection risk.

Skips quality checks/repairs and performs a single-pass rewrite. Output may have more errors and be more detectable.

string

default:"heavy"

Selects the humanizer model. If omitted, requests use heavy.

Show Available model options

Default. Runs the full StealthGPT humanizer pipeline and is designed for AI detector bypass.

Fast AI-smell cleanup that keeps the text mostly unchanged. This mode is not designed to bypass AI detectors.

boolean

default:"false"

deprecated

Removed. The 10x premium engine has been replaced by the Stealth Agent endpoint, which runs a full research → write → humanize pipeline (with optional fact-checking and image generation).The business field is still accepted in the request body for backward compatibility, but it has no effect: all /api/stealthify requests run on the standard engine and are billed at the standard rate. For premium-quality, long-form output, send your prompt to POST /api/stealthify/agent instead. See the Stealth Agent overview and guide.

boolean

default:"true"

Controls how non-English input is returned after processing. When true (default), non-English input will be kept in its localized language. When false, non-English input will be returned in English.

string

default:"turnitin"

deprecated

Deprecated. Retained for backward compatibility only and has no effect on model behavior. You can safely omit this field; all requests use the same model.

string

default:"text"

Controls the formatting of the returned content.

Show Available output formats

Default format. Returns plain text output.

Returns formatted content with markdown syntax (headings, lists, bold, etc.).

Response

string

The generated or rephrased content

number

Human-likeness score from 0 to 100. Higher is better: a higher score means the content reads as more human and is less likely to be flagged as AI; a lower score means it is more likely to be detected as AI-generated. (The field name is historical — treat a higher value as the better result.)

number

Number of words remaining in your account after this request

number

New: Replaces tokensSpent. Number of words used for the content generation or rephrasing.

string

Whether the request was billed from prepaid words (prepaid) or pay-as-you-go metered billing (payg).

number

If billed via pay-as-you-go, the number of words added to metered usage for this request (0 when billed from prepaid).

number

deprecated

Number of tokens used for the content generation or rephrasing

number

deprecated

Total number of tokens consumed by this request

number

deprecated

Number of tokens used by the system for processing the request

Example Request

curl --location 'https://stealthgpt.ai/api/stealthify' \
    --header 'api-token: YOUR_API_TOKEN' \
    --header 'Content-Type: application/json' \
    --data '{
        "prompt": "Explain the benefits of renewable energy",
        "rephrase": false,
        "writingMode": "essay",
        "tone": "College",
        "mode": "Medium",
        "qualityMode": "quality",
        "model": "heavy",
        "isMultilingual": true,
        "outputFormat": "markdown"
    }'

import requests

response = requests.post(
    'https://stealthgpt.ai/api/stealthify',
    headers={
        'api-token': 'YOUR_API_TOKEN',
        'Content-Type': 'application/json'
    },
    json={
        'prompt': 'Explain the benefits of renewable energy',
        'rephrase': False,
        'writingMode': 'essay',
        'tone': 'College',
        'mode': 'Medium',
        'qualityMode': 'quality',
        'model': 'heavy',
        'isMultilingual': True,
        'outputFormat': 'markdown'
    }
)

print(response.json())

const axios = require('axios');

axios.post('https://stealthgpt.ai/api/stealthify', {
    prompt: 'Explain the benefits of renewable energy',
    rephrase: false,
    writingMode: 'essay',
    tone: 'College',
    mode: 'Medium',
    qualityMode: 'quality',
    model: 'heavy',
    isMultilingual: true,
    outputFormat: 'markdown'
}, {
    headers: {
        'api-token': 'YOUR_API_TOKEN',
        'Content-Type': 'application/json'
    }
}).then(response => {
    console.log(response.data);
});

Example Response

{
  "result": "Renewable energy offers several significant advantages in our modern world. Students and researchers point to multiple benefits like reduced carbon emissions, which helps fight climate change. These energy sources, including solar and wind power, represent inexhaustible resources unlike finite fossil fuels. Many communities find economic advantages through job creation in the growing renewable sector. Additionally, these technologies typically require less maintenance after installation and reduce dependency on foreign energy imports. Advancements continue making these options more cost-competitive, with prices dropping significantly over recent years. While challenges exist in implementation, the long-term benefits to environmental health, economic stability, and energy independence make renewable energy sources increasingly attractive options for our global energy needs.",
  "howLikelyToBeDetected": 92,
  "wordsSpent": 260,
  "remainingCredits": 985000,
  "billingMode": "prepaid",
  "meteredChargedCredits": 0,
  "systemTokensSpent": 0,
  "tokensSpent": 0,
  "totalTokensSpent": 0
}

Usage Notes

For optimal performance, we recommend keeping responses under 2,000 characters
When rephrase is true, send only the source text in prompt — no “humanize / rewrite / make undetectable” wrappers
When rephrase is false, the quality and relevance of generated content depends on the phrasing of your prompts
For more advanced usage techniques, see our Advanced Usage Guide

Workflow patterns Writer & Humanizer Async Runs

Getting Started

Endpoints

Stealth Agent

Integrations

Resources

Writer & Humanizer

Request Parameters

Response

Example Request

Example Response

Usage Notes

​Request Parameters

​Response

​Example Request

​Example Response

​Usage Notes

Request Parameters

Response

Example Request

Example Response

Usage Notes