ScanForAI vs CheckForAI: one of these is offline.
★★★★★ 4.6 from 1050 user ratings
The honest version first: CheckForAI has shut down. Its site now shows a sunset notice and the detector no longer runs. Here's what it was, what happened, and what to use if you're looking for a CheckForAI alternative that's free and explains its scores.
The short version.
| ScanForAI | CheckForAI | |
|---|---|---|
| Status | Live, actively maintained | Discontinued — checkforai.com shows a sunset notice (checked August 2026) |
| Price | Free — scanner, accounts, history, API | Was free — a nonprofit project for individuals |
| What you get back | Score plus the evidence: AI-leaning lines marked in your text, patterns named in plain English | Returned a headline AI-likelihood read (per third-party directories); no longer retrievable |
| Detection approach | Own engine, retrained against current-generation model output; failure modes documented on the accuracy page | Directories described OpenAI's RoBERTa-base GPT-2 detector plus its own filters — an early-generation stack; its final form isn't verifiable now |
| Framing | A signal, not a verdict — we say "too short to judge" instead of guessing | Aimed to "limit false readings" per its directory listings — a goal we respect |
| Per-scan size | 20,000 chars anonymous · 50,000 free account — real enforced limits | Unpublished; the service is no longer available to measure |
| Extras | Injection scan · image AI check · batch scan · URL scan · API | — |
CheckForAI details come from its own sunset page (checked August 2, 2026) and third-party directory listings of the retired product; since the service is offline, its historical behavior can't be re-verified — where we aren't sure, we say so. CheckForAI is a project of its creators; ScanForAI is not affiliated with or endorsed by them. We publish no accuracy percentages for either tool — nobody's are independently settled.
When CheckForAI was the right call — and what replaces it.
CheckForAI deserved its users: free, simple, no account, run by people who cared enough to say they wanted to limit false readings. You can't choose it anymore — the sunset notice is polite and final. If it was your quick-check tool, the fair question isn't "who wins", it's what carries those habits forward. Free and instant matters; so does a detector that's still being retrained as models change.
If you liked: free, no signup
The ScanForAI scanner works the same way — paste, scan, done. No account, up to 20,000 characters, and nothing is stored on anonymous scans.
If you liked: careful, not accusatory
That instinct was right. We go further than a score: the AI-leaning lines are marked in your text with plain-English reasons, so a flag becomes a conversation instead of a verdict.
If you need old CheckForAI results
We can't help there, and its sunset page offers no archive — only a contact address. Treat any surviving screenshot of its scores as historical, not evidence: detectors staled fast between 2023 and today.
Where we say no
We don't do "probability a human wrote this" theatre, we publish our failure modes, and we tell you when text is too short to judge instead of guessing. Other active tools (GPTZero, Copyleaks) are legitimate choices too — two agreeing detectors beat one.
Common questions.
Is CheckForAI still working?
No. As of August 2026, checkforai.com shows a sunset notice: "CheckforAi was a free nonprofit project for individuals. We have sunset the service to focus on new projects." The detector itself is offline.
What happened to CheckForAI?
It was a free, nonprofit AI-detection project. The team retired it to focus on new work — their sunset page points questions to a new contact address rather than a replacement detector. No migration path or archive of old results is offered on the page.
What is a good free CheckForAI alternative?
If what you liked was free, no-signup checking, ScanForAI does that — 20,000 characters per scan with no account, nothing stored — and adds what CheckForAI never showed: the AI-leaning lines marked in your text with plain-English reasons. GPTZero and Copyleaks are also active alternatives; running two tools and only acting when they agree is sound practice with any detector.
Was CheckForAI accurate?
There are no independently settled accuracy numbers for it — or for any detector, including us. Third-party directories described it as built on OpenAI's RoBERTa-base GPT-2 output detector plus its own filters, an early-generation approach. Model output changes fast, which is why any detector needs constant retraining — and why an unmaintained one grows stale. That is an argument for using maintained tools, not a claim about any specific score CheckForAI produced.