About
Refrazr is built by a team of engineers and NLP researchers who got tired of watching well-written text get flagged as AI-generated — and decided to understand how detectors actually work, and why they flag writing they shouldn't. Eight months of iteration later, the engine runs 60+ post-processing rules derived by hand-analyzing where each AI rewrite still leaked patterns. Tested on GPTZero, Turnitin, Sapling, Originality.ai, and Winston AI.
What we do
AI detectors — tools like GPTZero, Turnitin's AI indicator, Sapling, Originality.ai, and Copyleaks — don't look for plagiarism. They look for statistical patterns in how language models generate text. Those patterns are real and consistent: LLMs produce unnaturally uniform sentence lengths, overuse certain transition phrases, construct symmetrical parallel clauses, and favor a specific vocabulary set that signals machine authorship.
Refrazr addresses those patterns directly. Our humanization engine analyzes incoming text across eight scoring dimensions, identifies which AI fingerprints are present, and rewrites the text at the structural level — not just swapping synonyms. The result is content that reads like a person wrote it, because the patterns that detectors measure have been eliminated, not disguised.
We help content creators working with AI drafts, non-native English speakers who use AI to overcome language barriers, marketers producing content at scale, and anyone whose genuine writing has been incorrectly flagged by an AI detector. The free tier is permanently free — 500 words per day, no credit card required.
Our approach
Simple paraphrasers change what the text says. Refrazr changes how it was written. The LLM receives your text along with a pattern-by-pattern breakdown of what was detected and explicit instructions to break each structural fingerprint — not to "rewrite in your own words," but to fix the specific patterns that trigger detection.
The LLM rewrite is the first pass. After the model finishes, 60+ deterministic post-processing rules run: stripping AI vocabulary, enforcing sentence burstiness, breaking parallel structure, adjusting transition density. The probabilistic model catches big patterns; the rule layer handles the residue.
Our rules were developed through extensive analysis of 10,000+ AI-generated texts and testing against GPTZero, Turnitin, Originality.ai, Copyleaks, and Sapling. We don't optimize for a single detector — we target the underlying statistical patterns that all major detectors use.
We show you the AI score before and after humanization, with a breakdown of which patterns were detected and which were resolved. You shouldn't have to submit to an external detector to know if your text passes. The methodology is fully documented — see our methodology page.
Who built this
We are engineers and NLP researchers who got tired of watching well-written text get flagged as AI-generated — and decided to understand how detectors actually work, and why they flag writing they shouldn't.
The problem with most humanization tools is that they approach the wrong signal. Detectors like GPTZero and Turnitin do not just check for unusual words. They measure structural properties of text: burstiness (the variance in sentence lengths), perplexity (how predictable word choices are), transition density, vocabulary distribution, and passive-to-active ratios. A tool that only swaps synonyms does not move these metrics.
We spent eight months building a post-processing pipeline that works at the structural level. The current implementation has 60+ rules across 8 scoring dimensions. When text goes through Refrazr, it gets restructured — not just rephrased.
Every rule in the pipeline was reverse-engineered from detector behavior, not from guessing. We tested against GPTZero, Turnitin, Sapling, Originality.ai, and Winston AI continuously throughout development. The methodology and test corpus are published at /methodology — we do not keep this proprietary because confident results should be reproducible.
The pricing reflects our cost structure. Our backend routes text through DeepSeek V3 for standard requests, which costs a fraction of what GPT-4 costs per call. We pass most of that margin to users. Refrazr Pro is $6.99/mo. Undetectable.ai charges $19. The difference is not a gimmick — it is a routing decision.
If Refrazr does not work for your text, we should not have your money. Refund policy: 7 days, no questions asked. Email Contact us from the address you used to buy.
Who uses it
AI drafts save hours of work, but raw AI output reads like AI output. Editors, readers, and Google's quality systems all notice. Refrazr converts AI-generated drafts into content that reads like it came from a skilled human writer — with natural rhythm, genuine variation, and no AI jargon.
Using AI to help express ideas in a second language is completely legitimate. Being flagged as an AI author for doing so is not fair. Refrazr helps non-native English speakers submit work that reflects their thinking without triggering false-positive detection.
Marketing teams using AI to scale content production need that content to rank, convert, and not get flagged. Refrazr runs at API scale — the Business plan includes API access for teams that need to process content programmatically.
AI detectors have real false-positive rates. Some human writers have writing styles that happen to trigger detection. Refrazr can analyze your text, identify which patterns are triggering the detector, and rewrite those specific sections — giving you clean output that no longer resembles the AI patterns it was falsely matching.
Privacy
We don't store your text. The process is: receive text → rewrite → return result → discard. Nothing you paste into Refrazr is logged to a database, shared with third parties, or used for model training. The only metadata we log is what's required for billing: timestamp, word count, and success/fail status.
Read the full details in our Privacy Policy. The short version: your content is yours and we never see it after the request completes.
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Free tier: 500 words/day, no account required.
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