404 is a physical book containing over 65 cryptic puzzles. There are no instructions, and it's up to you to decide what you must do to solve the puzzles on each page. You will probably want to write in the book, and sometimes cut it up or manipulate it. Solve the puzzles on each page to reveal the answer code, then enter them on this website to verify them. If you are wrong, but on the right track, the answer parser built into the website will tell you so. The website will also provide access to progressively more specific hints, so the puzzles will be accessible to all abilities of solver.
You will need to think creatively to extract answers from the book. If you are correct, the website will tell you that you have been successful. As you progress, you will also receive further communications from the organization who sent you the book, delivered via the website. These will reveal story elements which delve deeper into the enigmatic world of 404.
There is some similarity in the types of deduction you will need to make, but 404 will take you considerably longer to solve than an escape room. 404 has over 60 puzzles that may in some cases individually take you half an hour or more to puzzle out. Even the fastest solvers have taken a couple of weeks to complete the entire book.
No. All of the puzzles can be solved offline with a pen or pencil, and occasionally a pair of scissors, although you may sometimes want to use the internet to look up some well-known codes to help you solve certain puzzles. There is no extra content revealed on the 404 website which will help you solve the puzzles, so you are not at a disadvantage if you choose to solve it entirely offline.
Every puzzle is designed to be solved, so there are clues on every page – if you know how to interpret them. If you get really stuck, the website will give you progressively more direct hints. Just scan the QR code, or navigate to the relevant page on this site, and click the 'Get a hint' button.
Once you're on the page for the particular code, type in your answer and click 'Submit answer' to find out if it's correct.
Yes. Scan the puzzle's QR code, or locate the relevant page on this site, and click the 'Get a hint' button. You can keep clicking on it to get progressively more direct hints, if you wish to do so.
Great! Visit the 'Hidden codes' page and type in what you've discovered. You can find it at the bottom of the list of puzzles page.
No. When you enter a correct solution into the website, you will sometimes also unlock a short message from the organization that sent you the book. The story elements don't reveal any extra information that is needed to solve the other puzzles – they just journey a bit deeper into the world of 404.
No – but we recommend you do. Although most puzzles are designed so that they can be solved entirely on their own, without needing to have solved any of the puzzles that come before it, there are some exceptions to this. Another reason to solve in order is that - in general - they become progressively more challenging as the book goes on. Not just that, but the extra story elements on the website also will make more sense if revealed in increasing code order.
If you've entered a code which is almost correct, but not quite, the website will in specific situations tell you that you're close to the correct solution. This system can also be used to check 'part way' answers - so even if you know an answer is wrong, you can type it in to see if you're on the right track.
Between one and five. Next to the code number – which is usually at the bottom-right of the page – there are a number of underlines which indicate exactly how many words an answer will require. So, if there are four underlines, there will be four words in the answer. The width of the underline is meaningless and is not intended to give an indication of the lengths of the words required in the answer. The exact same underlines are repeated on the website, as a reminder prompt.
All of the puzzles consist of one or more words in their answer codes, except for one which also includes a number as one of the 'words' – but it will be obvious that you've solved it correctly when you get to that particular code. None of the other solutions use numbers.
Note that 'words' also includes names that would have been familiar to Plato. What this means is that classical names from antiquity might be involved.
It's always worth looking up unknown words or names after solving – usually they have relevant meanings.
You need to get all alphabetic and numeric characters correct, and to include spaces between words as intended. Beyond that, anything else is ignored - as are extra spaces. In a few specific cases, slightly incorrect answers are also accepted where it is clear the puzzle is completely solved. (The intended answer is always shown after solving).
On the bottom-left hand corner of every puzzle page is a QR code, which takes you directly to the page where you can enter the answer code for that page. Point your smartphone camera at it and - in most cases - a pop-up link will appear that you can tap. If your phone does not offer this function, then you may be able to instead download a free QR-scanner app. It's not necessary to use the QR codes, however – they are just a shortcut that takes you to the right page on the website for the puzzle you're working on. If you don't want to (or can't) scan the QR codes, you can just follow the direct links on this website from the 'Solve' page.
Yes. Every puzzle is designed to be solved, and all the information you need is somewhere in the book, except for a small number of very well-known codes. You may occasionally want to use the internet to look up one of those codes that you've identified is being used on a puzzle page, but you'll know when you would need to do that. There is no extra puzzle content hidden on this website, or anywhere else on the internet. There is story content to unlock, however.
If you want it to, yes. Create an account (for free) by choosing a username and password. After that, it will remember your solve status for each puzzle, as well as which hints you have taken. You can also use the site without logging in, if you prefer.
Technically, yes, but it won't be much use. You can't solve any puzzles without it.
The book was crowdfunded by backers on Kickstarter and Indiegogo in early 2019, and copies were initially only available to those backers. As of January 2020 the book is now available to buy from Amazon.
That depends on who you believe, since the book has been sent from a shadowy organization known as The Republic, deep inside the secretive Kingdom of States – which you'll learn more about as you solve the pages. Or, alternatively, take a look at our credits page.
Original Kickstarter backers received an additional cryptic letter with their books. This was an exclusive item and is no longer available. It added extra puzzles, but is not in any way required to solve the book.
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