On June 14 I'll be "celebrating" four months since I lost a job offer to a Chrome extension.
It was a Tuesday, a gray February morning, when I read one line from a recruiter and realized that my offer, all $180,000 of it, was gone.
Back then, like half the people in my prep Discord, I was running a browser extension during coding tests (one of those overlay tools that sits on top of the assessment page). I had a Codility test in the pipeline for a role I wanted badly, we were already past the salary conversation. With $180,000 on the table, that offer was the most precious thing in my pipeline, and also my entire plan for the year.
The amount of caution I brought to that test was directly proportional to that. Threads about candidates getting flagged were being posted all the time. Proctoring horror stories and silent rejections were the norm.
All that reading caused me to be a bit paranoid about what an assessment can actually see. When the test loaded and asked me to share either one tab or my whole desktop, I picked the tab, the "safe" one. Friends were even making fun of me because of that. I thought I was doing everything right.
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Try InterviewMan FreeBut no matter how many precautions I had in place, I missed one. An essential one. I wasn't "paranoid" enough to protect myself from the screen recording the company had turned on without telling anyone. The whole thing had looked like a normal timed assessment to me, from start to finish.
A few days after the test, a reviewer at the company watched my recording back. He saw the extension. I had been running that overlay through the entire session, so it was sitting there in the frames he went through, right next to my half written solution.
From there, things stacked up fast, because proctoring had been on the whole time and Codility logs all of it: every time you leave the test tab, when you left, how long you stayed away, how many times. The paste monitor had been running too, that one is on for every Codility test, proctored or not. Any block of code that appears in the editor without being typed gets stamped: a flag + the exact timestamp of the paste.
But it didn't stop there. In 2025 they had also added AI output pattern matching, and someone from my old study group had already been thrown out over exactly that pattern on his CodeSignal, twenty quiet minutes and then fifty clean lines appearing in ninety seconds, because nobody believes a human writes like that under pressure.
My offer, my precious offer... The full email was a single sentence, irregularities observed during the assessment review, and I sat in my car for probably ten minutes after reading it before I drove home.
My coworker was the first person that I was able to get real answers from. Although he runs Codility hiring at a different company, he was happy to pull the hiring dashboard up on his laptop, that was over pizza at his place the weekend after. This way, I got to see my own disaster from the reviewer side.
Halfway through the pizza, I learned that the flags page is the first thing most managers check, before they even look at your code. My extension was never caught by any of that automation though, it got caught because a human reviewer had direct access to every frame of my screen.
Armed with all this information, I asked him the only question I still cared about, which was what Codility can actually see. The answer calmed me down more than anything else did that month: Codility runs in the browser, the proctoring sees the assessment tab, the webcam, the screen recording, and that is the entire wall. Codility cannot scan the processes running on your machine, there is no mechanism for it to detect a desktop app that never touches the browser page.
It was a disturbing, unpleasant event, that caused me lots of grey hairs. It would have been a shame if I wouldn't have learned anything out of it, right?
Never assume proctoring is off: not when the invite says nothing, not when the recruiter sounds casual, not when the test looks like a plain timed assessment, never. Some companies never tell you at all. You never know who's going to watch your recording back. What saved me afterwards was recording my own screen during a practice session and watching the footage back, if you can see your tool in there, the hiring team can see it too.
My story turned out ok, eventually. Nothing irreversible happened, I did my damage control and moved my whole setup to InterviewMan, which we built as a desktop app for exactly this situation. Twelve bucks a month on annual, 20 plus stealth features in the base price, nothing sold separately as an addon. Cluely charges one hundred thirty dollars extra for its stealth mode, LockedIn caps you at ninety minutes a session and costs one hundred nineteen ninety nine.
I ran it on one proctored Codility and one unproctored, zero flags on either. I recorded my own screen during both and went through the footage frame by frame, the overlay was not in a single frame. It hides from screen capture, from the dock, from Activity Monitor, from the process list. My typing looked like mine too, I read the hints and wrote the code my own way, deletions and corrections and all.
We are at 57,000 users and 4.8 stars from 257 reviews now, and I could not find one single report of anyone getting caught on Codility with it.
But I do hope that no one else will ever have to learn the difference between a browser extension and a desktop app the way I did.
I never found out who reviewed my recording.
I remember that the recruiter had been friendly through the entire process, and that the final email didn't even have a greeting on it. Whoever wrote it probably believed they were catching a cheater red handed, and with what that recording showed, I can't really argue.
After that, I stopped checking whether the role ever got filled, I didn't want to know anything, I didn't care anymore. I was just furious with myself for being so naive and letting my guard down when I shouldn't have. A hundred and eighty thousand dollars, one Chrome extension. I should have known better.
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