Grubby AI Review

How I Tested

I generated a 218-word paragraph on teenage mental health using ChatGPT and kept it as my control sample. Not a word of it was edited by hand. I ran that paragraph through Grubby’s humanizer twice, once while logged out and once from a free account, then pushed the output straight into a detector without cleaning it up first. After that I tested the summarizer on a PDF and the AutoTyper on a short sentence. Every screenshot below comes from a single session on 27 August 2026, on the free plan.

First Impressions From a Logged-Out Session

The logged-out editor counts your input against a 5,000 word allowance, which sets an expectation the free account does not honour. My paragraph processed without trouble. Three sentences of the rewrite appeared, then the remainder blurred out behind a Subscribe to Unlock panel.

The mode selector was the more revealing part of that screen. Grubby asks you to pick a target detector before it rewrites anything, with Turnitin flagged as the premium choice. The tool is openly built around beating specific detection systems rather than improving writing.

The Humanizer Against GPTZero

Signed in, the editor opens with a banner promising that Grubby is the only humanizer guaranteed to bypass Turnitin’s AI detector. I set the mode to GPTZero, which put an Optimized for GPTZero badge in the corner. My 218-word input came back as 257 words.

The rewrite reads worse than the input it replaced. The words teenagers and social media repeat in almost every sentence, and the 39 words Grubby added carry no new meaning. I then used the tool’s own Copy & Verify button, which hands the text over to a detector for checking.

GPTZero returned 100% AI and 0% human, with a note saying it was highly confident the text was machine generated. Every sentence in the passage came back highlighted.

That result came from the mode Grubby built for that exact detector.

The 300-Word Ceiling Is Monthly, Not Per Input

Published reviews of Grubby describe the free plan as capped at 300 words per submission. The dashboard tells a different story. The 300 words are a monthly allowance with a fixed reset date, and my one 218-word paragraph consumed 73% of it in a single click.

When I pasted a second sample to test consistency, the tool stopped before processing it.

82 words will not cover a paragraph. A free user gets one short passage per month, which makes any serious evaluation of the tool impossible without paying.

The Summarizer Did Not Finish

I uploaded a PDF to the summarizer to see how the wider toolset held up. Text extraction worked cleanly and 2,943 words landed in the input pane.

Clicking Summarize started a processing state with placeholder bars filling the output pane.

The pane then dropped back to its empty state with nothing generated. I repeated the attempt several times and got the same outcome each time.

AutoTyper Was the One Feature That Delivered

AutoTyper connects to Google Drive and types your text into a document at a slow, controlled pace. I linked my account, pasted a single sentence about solar panel efficiency, and selected the 30 minute duration.

The session dashboard tracked progress live, showing 79.9% complete with 23 of 29 words placed and an estimated 29 minutes left.

The sentence arrived in the Google Doc exactly as I entered it.

AutoTyper does precisely what it advertises. Its purpose is to build a believable edit history inside Google Docs so a submitted file does not look pasted in one block. Out of everything I tested, it was the only feature that finished the job it was given, and that job is defeating document forensics rather than producing better writing.