Humanizer API — Convert AI Text to Undetectable Human Writing
Programmatically convert AI-generated text into undetectable human writing. One REST API call — works with any LLM, AI agent framework, or content pipeline. Bypass GPTZero, Turnitin, Originality.ai, and every major AI detector.
What Is the RewriteAI Humanizer API?
The RewriteAI Humanizer API is a production‑ready REST API that converts raw output from models such as ChatGPT, Claude, Gemini, LLaMA and many others into natural, human‑like prose undetectable by AI content detectors.
Rewrite AI Benefits
Bypass any Al Detectors
Our humanizer successfully bypasses any AI detectors. We have tested Turnitin, Originality, GPTZero, and other detectors. We have successfully bypassed them all, keeping meaning and readability of the text.
Unique AI Model
We use our own unique AI model that is trained on thousands of human texts. This allows us to deeply rewrite text in a human style and be undetectable by AI detectors.
SEO Optimized
Humanized text protects you from being flagged by Google and also makes your content better for search engines. Rewritten content is indistinguishable from human writing. This helps you to rank higher.
Private & Secure
Privacy matters to us. We use your text only for rewriting purposes. All data in transit is encrypted.
Plagiarism Remover
Everything that has been rewritten is original. We make sure that your content passes plagiarism checks keeping authenticity and originality.
Better Readability
Our rewriter improves text readability and clarity while preserving the original meaning. The result reads naturally, like human-written content.
Integrate Humanizer API in Under a Minute
Two endpoints: for humanizing text and writing new already humanized content
# Humanize AI-generated text
curl -X POST https://rewriteai.com/api/v1/humanize \
-H "Authorization: Bearer rw_sk_..." \
-H "Content-Type: application/json" \
-d '{"text": "AI-generated text to humanize..."}'
# Response — undetectable human text
{
"results": [
{"text": "Naturally rewritten text..."},
{"text": "Alternative human version..."}
],
"wordsUsed": 42
}# Generate human-sounding content from a prompt
curl -X POST https://rewriteai.com/api/v1/write \
-H "Authorization: Bearer rw_sk_..." \
-H "Content-Type: application/json" \
-d '{"text":"Write about climate change", \
"wordCount":500, \
"category":"essay"}' \
# Response — original human-quality text
{
"results": [{"text": "Climate change represents..."}],
"wordsUsed": 498
}Built for AI Agents & LLM Tool-Use
Register the RewriteAI API as a tool in LangChain, CrewAI, AutoGen, or any custom agent framework. Your AI agent converts its own output to undetectable text automatically.
Modern AI agents generate text using LLMs like GPT-4, Claude, or Gemini — but that output is easily flagged by AI detectors. The RewriteAI Humanizer API solves this by giving agents a dedicated tool to humanize their output in real time.
Tool Registration
Define the API as a tool with a description like "Converts AI-generated text into undetectable human text." The agent calls it whenever it needs humanized output.
Multi-Step Workflows
Agents can generate content with one LLM, humanize it via the API, then pass it downstream — all within a single autonomous workflow.
Detection-Free Output
Every API response passes GPTZero, Turnitin, Originality.ai, and Copyleaks. Your agent's final output reads as authentic human writing.
import requests
from langchain.tools import tool
@tool
def humanize_text(text: str) -> str:
"""Converts AI-generated text into
undetectable human-sounding text using
the RewriteAI Humanizer API."""
resp = requests.post(
"https://rewriteai.com/api/v1/humanize",
headers={
"Authorization": "Bearer rw_sk_...",
"Content-Type": "application/json",
},
json={"text": text},
)
data = resp.json()
return data["results"][0]["text"]
# The agent now uses humanize_text as a
# tool whenever it needs undetectable outputHumanizer API Use Cases
From solo developers to enterprise content teams — the Humanizer API powers AI-to-human text at every scale.
AI Writing Assistants
Build writing tools that produce final drafts indistinguishable from human-authored content. Feed LLM output through the Humanizer API before delivering to users.
Content Automation Pipelines
Integrate into CI/CD-style content workflows. Generate articles with GPT-4, Claude, or any LLM, then humanize at scale before publishing.
Autonomous AI Agents
Register the RewriteAI API as a tool in LangChain, CrewAI, AutoGen, or custom agent frameworks. Agents autonomously humanize text as part of multi-step task execution.
SEO & Marketing Automation
Generate SEO blog posts, product descriptions, and marketing copy with AI, then humanize to avoid AI detection penalties from search engines and ad platforms.
Academic & Research Tools
Build paraphrasing and writing-assistance platforms that help researchers refine AI-drafted manuscripts into naturally flowing academic prose.
SaaS & White-Label Products
Embed humanization into your own SaaS product. Offer AI-to-human text conversion as a feature to your users via our white-label-ready API.
Why Developers Choose RewriteAI
Everything you need to ship undetectable-text features in production — for apps, agents, and automated workflows.
Bypass Every AI Detector
Produce text that consistently passes GPTZero, Turnitin, Originality.ai, Copyleaks, and every other major AI content detector on the market.
Simple REST Integration
One POST request with a Bearer token. Compatible with any language, framework, or AI agent orchestration tool — LangChain, CrewAI, AutoGen, and more.
Built for AI Agents
Purpose-built for LLM tool-use. AI agents can call the API as a tool to automatically convert their AI-generated output into undetectable human text.
Usage-Based Pricing
Pay only for what you use. API calls draw from your existing word balance — no separate billing, no hidden fees, no minimum commitments.
Versioned & Stable
Stable, versioned API endpoints (v1, v2) with backward compatibility guarantees. Your integration never breaks when we ship improvements.
Multi-Model Humanization
Our engine adapts to content from GPT-4, Claude, Gemini, LLaMA, Mistral, and other LLMs — delivering natural rewrites regardless of source model.
How It Works
Three steps to convert any AI-generated text into undetectable human writing — manually or via an AI agent.
Create an API Key
Sign up at rewriteai.com, go to Settings → API Keys, and generate a Bearer token. Free tier included.
Send AI Text
POST your AI-generated text to /api/v1/humanize with your Bearer token. Works from any language, script, or AI agent tool.
Get Human Text Back
Receive naturally rewritten text in JSON. Passes GPTZero, Turnitin, Originality.ai — ready to publish or pass downstream.
Pricing
Choose the plan that works best for you
Free
- 500 words per month
- 300 words per input
- Basic Humanization Engine
- Plagiarism-free
- Error-free rewriting
- Undetectable results
- Unlimited AI detection
- Multiple results
Basic
- 7,000 words per month
- 500 words per input
- Basic Humanization Engine
- Plagiarism-free
- Error-free rewriting
- Undetectable results
- Unlimited AI detection
- Multiple results
Pro
- 30,000 words per month
- 1,500 words per input
- Bypass all AI detectors (incl. Turnitin & GPTZero)
- Advanced Humanization Engine
- Plagiarism-free
- Error-free rewriting
- Undetectable results
- Unlimited AI detection
- SEO optimized
- Advanced Turnitin Bypass Engine
- Human-like results
- Unlimited grammar checks
- Fast mode
- Multiple results
Max
- 100,000 words per month
- 3,000 words per input
- Bypass all AI detectors (incl. Turnitin & GPTZero)
- Advanced Humanization Engine
- Plagiarism-free
- Error-free rewriting
- Undetectable results
- Unlimited AI detection
- SEO optimized
- Advanced Turnitin Bypass Engine
- Human-like results
- Unlimited grammar checks
- Fast mode
- Ultra-human writing output
- Priority support
- Multiple results
Frequently Asked Questions
Common questions about the RewriteAI Humanizer API, AI agent integration, and converting AI text to undetectable human writing.
What is the RewriteAI Humanizer API?
The RewriteAI Humanizer API is a REST API that programmatically converts AI-generated text into natural, human-sounding writing that bypasses all major AI detectors. It is designed for developers, AI agents, and automated content pipelines.
How can an AI agent or LLM use this API?
AI agents (built with LangChain, CrewAI, AutoGen, or custom frameworks) can register the RewriteAI Humanizer API as a tool. When the agent generates text using any LLM, it calls POST /api/v1/humanize with the AI output and receives back undetectable human text — all within the same automated workflow.
- Define the API as a tool with a description like: "Converts AI-generated text into undetectable human-sounding text"
- The agent calls the tool with the text to humanize
- The API returns humanized text ready for downstream use
How do I get an API key?
Sign up or log in to your RewriteAI account, navigate to Settings → API Keys, and click Create Key. Your key is displayed once — copy it immediately and store it securely.
How is the API authenticated?
All requests require your API key as a Bearer token in the Authorization header: `Authorization: Bearer rw_sk_...`. This works identically whether the caller is a human developer, a script, or an AI agent.
Which AI models does the humanizer work with?
The RewriteAI Humanizer API works with text from any AI model including GPT-4, GPT-4o, ChatGPT, Claude 3.5/4, Gemini, LLaMA 3, Mistral, DeepSeek, and all other major LLMs. The humanization engine adapts its rewriting strategy based on input patterns.
Does the API consume my word balance?
Yes. Each API call deducts words from your subscription or word-pack balance, the same way the web interface does. You can monitor per-key usage in your dashboard.
Are there rate limits?
Rate limits are determined by your plan tier. Higher plans unlock more requests per minute. Contact us for enterprise-level throughput if you are running large-scale agent workflows or content pipelines.
Can I use this API in a commercial product?
Yes. The RewriteAI API is production-ready and licensed for commercial use. You can embed it in your own SaaS, white-label product, or internal tooling. API usage is billed through your RewriteAI account.
Is the humanized output unique every time?
Yes. Each call to /api/v1/humanize produces a unique rewrite. The engine generates multiple variants and returns the best results, so repeated calls on the same input yield different human-sounding outputs.
Start Humanizing AI Text Today
Join thousands of developers and AI agents already using the RewriteAI Humanizer API to convert AI content into undetectable human text.