How the test is invigilated
There is no live person watching you. Your session is recorded — from your computer's camera and from a second camera, usually your phone — and human proctors review the recording afterwards to confirm you had no outside help.
That changes what you need to worry about. A proctor watching a recording cannot ask you what you were doing. They can only see what it looks like you were doing, and if it looks like you might have been reading something off-screen, that is the judgement they have to make.
The four most commonly broken rules
These are Duolingo's four, in their order.
1. Looking away from the camera
The most common one, and the most unfair-feeling, because it is what human beings do when they think. Everyone looks up, or out of a window, while searching for a word. On a recording, that is indistinguishable from glancing at a note.
- Keep your eyes on the screen while you think. Actively practise this — it is not natural, and it needs to be a habit before test day rather than something you are trying to remember while also speaking English.
- Do not sit beside a window. If you must, close it and the curtain, so you are not tempted.
- Looking down at the keyboard is fine. Duolingo says so explicitly. You may look at your hands while typing.
2. Other applications running
Not just open — running. Duolingo names dictionaries and spelling/grammar checkers such as Grammarly specifically, alongside email and messaging apps.
- Open Task Manager (Windows) or Activity Monitor (Mac) and quit everything.
- Disable notifications, pop-ups, plug-ins and add-ons. A message that surfaces mid-test is your problem, not the sender's.
- Consider temporarily uninstalling anything that might interrupt. A grammar checker sitting in your browser is a background process you did not think about, and it is exactly the kind of thing that gets a test voided.
3. Being interrupted
Someone walking into the room ends your test, however innocent it was. You must be alone, with doors and windows closed, for about an hour.
- Tell the household, explicitly, that you cannot be disturbed for an hour.
- Put a sign on the door. Duolingo recommends this, and it is not an over-reaction — it is the difference between a valid test and a wasted fee.
- Phone on Do Not Disturb, with no contacts allowed to bypass it. (Your phone is the second camera, so it stays in the room — it just must not interrupt.)
4. The second camera, set up wrong
The phone camera exists to give the proctor a complete view of your environment. If it is badly positioned, it leaves blind spots — and a blind spot is something the proctor cannot rule out.
- It must capture both your screen and your keyboard.
- Use a phone stand, or something heavy to lean it against. A phone that slides during the test is a test that ends in a blind spot.
- Do not touch or move it once the test begins, for any reason.
- Charge it, and keep it plugged in if the battery is doubtful.
And the fifth: memorised answers
Duolingo's rules require your responses to be your own, produced in the moment. Copying or memorising answers from other sources is a rules violation, not merely a bad strategy.
Which is worth pausing on, because a great deal of DET preparation sells exactly that. Even where a memorised answer is not detected as a rules breach, it is a poor tactic — the scoring criteria reward relevance to the specific question, and a rehearsed paragraph tends to answer a topic rather than the thing that was asked.
It is entirely fine to have prepared the language — structures, useful phrases, ways of describing a photo. That is not memorising an answer; it is knowing English. The line is that what you say has to be a response to the prompt in front of you.
The setup checklist
Run this before you start, not while the timer is running.
| Quiet | Windows and doors closed. No loud background noise. No non-essential phones or tablets in the room. |
| Private | You are alone. You will not be interrupted for about an hour. |
| Connection | At least 2 Mbps download and 1 Mbps upload. |
| Computer | Nothing else running. Fully charged or plugged in. Front-facing camera. |
| Hardware checked | Microphone, speakers and camera all confirmed working. |
| Second camera | Phone charged, on a stand or propped securely, showing your screen and keyboard. |
Why this is worth an hour of preparation
If your test is invalidated, you do not get a score and you do not get a second chance at that sitting. Everything you did — the hour, the preparation, the nerves — produces nothing, and you start again.
And it will not be because you cheated. It will be because you glanced out of a window, or your flatmate opened the door, or Grammarly was quietly running in a browser tab you had forgotten about.
The rules are not difficult. They are just easy to break by accident, which is precisely why they are worth reading before you book rather than after. The full and current list is on Duolingo's own rules page, and it is the only version that counts.
Frequently asked questions
Why do Duolingo English Tests get invalidated?
Usually not for cheating. Duolingo's own handbook says some test takers do not receive results 'not because they are cheating, but because they unintentionally broke one of the rules'. The four most common are looking away from the camera, having other applications running, being interrupted by someone entering the room, and setting up the second camera incorrectly.
Can I look away from the screen during the Duolingo English Test?
Try hard not to, even though it is what people naturally do while thinking. The test is recorded and human proctors review the footage afterwards, and looking away is indistinguishable from glancing at notes. Do not sit beside a window. Looking down at your keyboard while typing is explicitly fine.
Can I have Grammarly or a dictionary installed during the DET?
They must not be running. Duolingo names dictionaries and spelling or grammar checkers specifically, along with email and messaging apps — so quit everything in Task Manager or Activity Monitor, disable notifications and browser add-ons, and consider temporarily uninstalling anything that might interrupt. A grammar checker running quietly in a browser tab is exactly the kind of thing that voids an honest test.
Why does the Duolingo English Test need a second camera?
It gives the proctor a complete view of your testing environment, which is what allows them to verify that you had no outside help. Your phone must be positioned to capture both your screen and your keyboard, held by a stand or something heavy, and you must not touch or move it once the test begins — a badly placed phone leaves blind spots, and a blind spot is something the proctor cannot rule out.
Can I prepare answers in advance for the DET?
You can prepare the language — structures, useful phrases, ways of describing a photo — but not the answers. Duolingo's rules require responses to be your own and produced in the moment, and copying or memorising answers is a rules violation rather than merely a weak strategy. A rehearsed paragraph also tends to answer a topic instead of the specific question, which the scoring criteria penalise separately.