For platforms, agencies and developers

AI humanizer API: humanize AI text inside your own product

Your platform already produces AI text. The humanizing step is what stops that text reading like a machine wrote it, and it is the step your users notice when it is missing.

The Undetected.ai humanizer API gives you that step as a call: send text and a tone, get back natural prose and the detection score that proves it cleared. No one has to paste anything into a browser.

The Humanizer

5 detectors live

Paste your AI-written text

Try:

Tone

Strength:

Your text is never stored or used to train models.

Cleared. Reads 100% human.

Before · flagged as AI

After · reads human

Talk to sales about API access See pricing

Volume priced · Detection score returned · Never stored or used for training

The short answer

Undetected.ai offers an AI humanizer API on its Team / API plan: you send AI-generated text and a tone, and the API returns a rewritten version in natural, human-sounding prose along with a detection score. It is priced by monthly word volume through sales rather than sold self-serve, it keeps the meaning of the original text intact, and it stores nothing you send. Self-serve browser plans start at $9 per month; programmatic access is arranged for teams and platforms that need humanizing built into a product or a bulk pipeline.

Last updated July 2026

What you can build

Three things teams build with a humanizer API

The API exists because copy-pasting into a web tool does not survive contact with a real content operation.

A humanize step in your product

If your app generates drafts, ads, listings, or descriptions with a model, the humanize call becomes the last stage of your generation pipeline. Your users get output that reads like a person wrote it, and you never build the rewriting layer yourself.

A bulk pass over a content backlog

Agencies and publishers with hundreds of AI-assisted drafts run them through the API in a batch instead of one by one. Every piece comes back rewritten and scored, so you know which ones were flagged before anything is published.

A pre-publish gate in your CMS

Score every draft on the way to publish and block the ones that read as machine-written. Because the API returns the detection reading, you can set a threshold and enforce a standard across a whole team without reviewing each piece by hand.

What the API does

The humanizer API at a glance

Capability	What you get
Input	AI-generated or AI-assisted text, plus the tone you want (standard, academic, casual or SEO).
Output	Humanized prose that preserves the facts, argument and structure of the original.
Detection score	The same reading the web gauge shows, returned with the rewrite so you can gate, log or display it.
Detector coverage	One pass tuned against GPTZero, Turnitin, Originality.ai, Copyleaks and ZeroGPT together.
Volume	A custom monthly word allowance agreed with sales, sized to what you actually process.
Data handling	Text is not retained after processing and is never used to train models.
Access	Team / API plan. Endpoint, key, rate limits and tone options are covered in onboarding.
Support	Dedicated support and onboarding, plus multiple seats and shared usage for the team.

Pricing is set against your expected monthly volume. Tell us what you process and you get a figure before you build.

Why Undetected.ai

What matters when you put a humanizer behind your own product

When the rewrite happens inside your app, your users blame you for a bad one. These are the things worth checking before you integrate anyone.

A score you can act on

A humanizer that returns only text forces you to trust it. One that returns a detection reading lets you gate on a threshold, retry, or show the user proof. That difference is the whole reason to have the score in the response.

Meaning that survives the rewrite

Synonym-swapping humanizers score well and read badly, and in an API that failure is invisible until a customer complains. Undetected.ai rewrites rhythm and phrasing while keeping the facts and the argument where you put them.

Text you do not have to worry about

The content you send through an API usually belongs to your customers, not to you. Nothing sent to Undetected.ai is stored after processing or used for training, so you are not quietly handing someone else's work to a training set.

Good questions

Questions about the AI humanizer API

Is there an AI humanizer API?

Yes. Undetected.ai offers a humanizer API on the Team / API plan, which is priced by volume and arranged through sales. You send text and a tone, and you get back a humanized rewrite plus its detection score, so your own product can humanize content without a person pasting into a web app.

How much does the AI humanizer API cost?

API access sits on the Team / API plan, which is volume priced rather than a fixed monthly figure. Self-serve plans run from $9 to $39 per month for browser use. If you need programmatic access, seats, and a custom word volume, contact sales and pricing is set against the words you expect to process.

What can I build with a humanizer API?

The common builds are a humanize step inside a content platform, a bulk pipeline that cleans a batch of AI-assisted drafts before publishing, and a pre-publish check inside a CMS. Anywhere your product already generates or ingests AI text, the API adds the finishing pass.

Does the API return a detection score?

Yes. The same detection reading you see in the web gauge is available programmatically, so your product can show users the before and after score, gate publishing on a threshold, or log the result for an audit trail rather than trusting the rewrite blindly.

Is my text stored or used for training?

No. Text sent to Undetected.ai is not stored after processing and is never used to train models. That holds for API traffic as well as the web app, which matters when the content belongs to your customers rather than to you.

How do I get API access?

Contact sales through the contact page and describe your expected monthly word volume and use case. Onboarding covers the endpoint, your key, rate limits, and the tone options, and pricing is agreed against your volume before you build.

Explore more

Put the humanize step in your pipeline

Tell us the volume you process each month and the shape of your integration. You get a price and an onboarding plan before you write any code.

Talk to sales See pricing

Volume priced · Meaning kept · Never stored or used for training