HumanPen vs StealthGPT: same students, different approach
The audiences overlap almost entirely. What differs is the shape of the tool and, more importantly, how you are meant to verify that it worked.
Competitor details verified 2026-08-01. Their own site is the authority.
The short answer
StealthGPT is a text-box tool with a detected-or-refunded guarantee and a bundled checker. HumanPen processes whole documents, makes no effectiveness guarantee, and instead supports importing the Turnitin report your institution issued so you can verify against your own data.
Side by side
| HumanPen | StealthGPT | |
|---|---|---|
| Input | Upload the document itself | Paste text, plus a Chrome extension |
| Output | The same file back, still editable | Plain text |
| Per-request word cap | None | Up to 20,000 words/request (Enterprise Unlimited plan) |
| Word-count control | Set a target word range; output converges on it, slight drift possible | None |
| Billing | Metered credits, never expire | Monthly subscription |
| Detection report import | Turnitin / iThenticate | None |
| Built-in detector | None | Yes |
| Effectiveness guarantee | None, by choice | Refund if detected |
| Agent / API integration | Skill, MCP, and REST API — callable from AI agents | API, MCP, and Chrome extension |
| Rewrite languages | English only | Multiple |
When to pick StealthGPT
- You want an explicit guarantee. We do not offer one; if that is decisive for you, they match your expectation better.
- You want an instant score after rewriting. They bundle a checker; we do not.
- You want a browser extension.
- You need a language other than English.
- Your text is short, so per-request caps never bind.
Why we make no guarantee, and where we stop
Detection systems keep updating - text that passes today may not after the next model iteration. Any "guaranteed to pass" promise is either hedged with conditions strict enough to rarely pay out, or is a promise about something outside the promiser’s control. We would rather put the effort into letting you verify it yourself: import the report your institution issued, we process only the flagged passages, and you re-check afterwards and compare. The data then comes from your institution, not from a checker we operate.
It is also part of why we do not bundle a detector: setting your own exam and grading it yourself is not very persuasive.
If a guarantee is what you are shopping for, read the terms and not the headline: which detectors count, at what score, how long the window runs after you pay, and what evidence you have to produce. That is not aimed at anyone’s in particular - it is how we would read our own, if we ever wrote one.
What we do not offer: a guarantee, a bundled detector, an extension, or any language but English.
FAQ
Why no detected-or-refunded guarantee?
Detection systems update, and we will not promise a result we do not control. We put the effort into verification you can run yourself instead.
Without a built-in checker, how do I know it worked?
Use your institution’s or a third-party detection service. We support importing Turnitin and iThenticate reports for targeting, and you can compare against a fresh report afterwards.
Which one is more effective?
We have run no head-to-head test and will not give you a fabricated number. Judge it on your own document.
Should I run it through theirs first, then yours?
We would not. Stacking rewriters compounds the risk to terminology accuracy and citation integrity. Process the original.
The only comparison that settles it is your own document
New accounts get 100 credits - enough to run a full section of your own writing through and judge the result yourself.
Try it on your document