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The Hack the Code Challenge is an online team-based coding and security competition open to coders aged 16 years and older on the day of the challenge (March 12, 2025), from around the world. There are two challenges: one for Replyers and one for professionals and students who don’t work for Reply. The challenge environment will be different, but the problem statement will be the same.
No. There are two challenges and two separate leader boards, so mixed teams are not possible.
No. To play on 12th March, you need to join a team, or create your own. By registering on the platform, you’ll get updates on upcoming online challenges.
No, this coding challenge is completely free!
You can register until 11th March, 23:59pm, CET.
Once you’ve registered, you can join a team, form one, or you can join our Discord Server in order to find participants to play with.
To update your details at any time, log in to your profile and click “Edit profile”.
Please send your cancellation request to challenges@reply.com.
To form your team, log in to the Reply Challenges platform, click the “Team up” button and select “Create new team”. Once you’ve formed a team, you’ll see it when you log in to the platform. You can also choose a team name and invite your friends. Just fill in their email addresses and send the invitation. Remember, Replyers play a challenge reserved for them. Mixed teams are not allowed.
Your team can have 1 - 6 people. A team can consist of one person, but you can always invite friends or colleagues to join your team. Plus, remember for this edition to look for coders and security experts to get more points and more chance to win.
No problem. You have until 11th March at 23.59 to join someone else’s team.
No, but you are free to leave your current team. They won’t receive any notification, so remember to tell them.
We strongly recommend you to practice the training problems before the competition starts. This year the competition is in the format of a Code Challenge together with some CTF challenges.
We recommend you to train with both Code Challenge and the CTF past problems in sandbox mode. That way, you can better understand the type of challenge you might get and how to submit solutions.
You can use any programming language to solve the problem.
Just visit the Reply Code Challenge and Cyber security Past Editions to find all the past editions' problems in a sandbox mode. In sandbox mode you can upload as many solutions as you want, as many times as you want. The training problem submission works just like the real challenge, except you’ll play alone and not in a team.
Please note that not all the CTF levels are available in sandbox mode, but for the level of this challenges (100 and 200) you can find enough material both in the learn & train section and in the Past editions with the best teams' write up files.
For the coding part: submit a solution by dragging and dropping it or uploading it from your computer. Each submission should contain at least one output file and at least one source code file. Note, the source file is not mandatory in sandbox mode.
In case of a CTF (Capture the Flag), you can enter the string of the Flag in a dedicated field in the game area.
Yes. You’ll see a list of scores for all your submissions.
No, but you’ll see your submission scores.
The platform supports the latest version of Chrome, Explorer, Firefox, Microsoft Edge and Safari. If you’re not sure what version you have, check here.
Try reloading the page, then try clearing your cache and cookies. If you’re still having problems, message the Reply Code Masters on chat or email challenges@reply.com.
You’ll need your own computer with an internet connection.
Just like most coding challenges, you can use your favourites.
On 21st March, at 4.30pm CET, we’ll publish the problem statement on the challenge platform. It will include the input files you can download from the challenge platform, where you’ll also submit your team’s solution files.
You can message the Reply Code Masters and Keen Minds via chat and on the Discord Server.
Yes. There are no restrictions on the development environment or programming language you use during the contest. You simply write programs to solve a task and submit the results as a text file to the challenge platform. You’re responsible for compiling and running your code on your own computer(s).
We’ll update the leaderboard regularly to show how teams are performing. We’ll also freeze it 30 minutes before the challenge deadline (but we’ll continue to update scores).
Yes, it’s an online-only coding competition.
On 12th March, at 3.30pm CET, we’ll publish the problem statement on the challenge platform. It will include the input files you can download from the challenge platform, where you’ll also submit your team’s solution files. Some extra input files will be locked: you and your team can unlock them solving the related security challenges in the capture the flag format. The categories proposed are: Misc, Crypto and Web, all at level 200.
Once you found the correct flag, you and your team can download the related input file and submit your solution as a traditional code challenge.
GAME BOARD AT THE START OF THE CHALLENGE
Yes, absolutely! Your team can still participate and aim for the best score using the unlocked input files. Even if you don't complete the security challenges, you can still achieve a good score.
Your team submits solutions by uploading a file to the challenge platform. Each submission must include at least one output file and one source code file. Please note that uploading the source file is mandatory.
If the input is blocked, you will first need to solve the Capture the Flag (CTF) challenge. Once you find the flag, you can download the input file and proceed to solve the challenge as you would in a traditional coding challenge.
We’ll calculate your team score by summing up the maximum score of each valid input file; the scoring system awards solutions that best optimise the problem. Reply Code Masters & Keen Minds may, at any time, reject a solution and invalidate its score. To settle ties, we’ll take time into account.
We’ll calculate your team score by summing up the maximum score of each valid input file; the scoring system awards solutions that best optimise the problem. Reply Code Masters may, at any time, reject a solution and invalidate its score. To settle ties, we’ll take time into account.
Your team can use public released libraries and tools, but your solution must use original code. To be valid, every submission must include a file containing the source code of the program you developed to generate the output. Each source code file must be a UTF-8 plain text file or an archive of UTF-8 files.
If you result in the top teams in the podium, you are requested to provide also the write up file for the CTF challenge: a document which explain in detail how you and your team found the flag.
The flag is a token or a string that matches the following regular expression: /\{FLG:.+\}/ where the content is any non-empty ASCII string (uppercase and lowercase letters, digits or symbols).
At the end of the code game, the Reply Code Masters will review and validate the best scoring submission from top-ranked teams on the leaderboard. The Reply Code Masters’ decisions regarding the rules of the coding competition are final.
We’ll publish a full list of results and notify all finalists no later than 10 days after the day of the challenge.
At the end of the challenge, the Reply Code Masters will review and validate the best scoring submission from top-ranked teams on the leaderboard. The winning team will get a reward up to 15.000€ (2.500€ each member). The second-placed team get a reward up to 6.000€ (1000€ each member) and the third 4.800€ (800€ each member). The Reply Code Masters’ judgement is final when enforcing competition rules and awarding prizes. We’ll send the winners details of how to claim their prize.
If you are a Replyer, the prizes will be different from the external competition. Each member of the first team will win a Mackbook Pro 14''. Each member of the second team will win a Playstation 5 Slim, while each member of the third team will receive a pair of headphones Bose QutietComfort.
Yes, you will get a certificate with the score and the ranking if your team send at least one valid submission.
You can win a prize for your university, too. The final score that your team will get during the Code Challenge will be added to the University Leaderboard.
A cool Reply Arcade Game cabinet for the communal areas in your university or a financial donation to support an educational or research project.
You just need to tell us the name of your university right after creating a team or joining an existing one.
The final score of your team will count for every person on the team: if in your team there will be students from different universities the points will be added to each of those.
Yes, you can, the University Students League is open to Alumni too. Right after creating your team, insert the name of the university where you studied and make it win.
No, you can't, but stay tuned for next communications on TamTamy about how to get the official t-shirt and the hubs where to play in the offices.
You’ll get some emails before and after the challenge, so check your mailbox regularly. You can always message the Reply Code Masters during the challenge via chat if you have questions.
All communications will be in English. Though you and your teammates can speak whatever language(s) you like! 😊
Reply Code Masters and Keen Minds are groups of Replyers passionate and experts about coding and security, developing this challenge in its versions: teen and standard. They write the problems and are responsible for enforcing all coding challenge rules. They’ll review submissions from teams and award prizes. They may exclude any participants or teams at any time, for breaching competition rules.
We want to make training sessions and the challenge fair for everyone. So never stop others from taking part – for instance, by overloading the challenge platform, or sending files containing malware, viruses or other code intended to interrupt, destroy or limit the operation of platform, software, hardware or telecoms equipment. This will result in instant disqualification. If you’ve spotted any cheating or unfair behaviour, email challenges@reply.com
Yes, you can use any of the AI tools you haver or you prefer.
Do you provide any learning materials?
We have a dedicated learning path with some concrete examples on how AI can support in the resolution of the problems for this challenge. Check the Learn & Train section to discover more and start practicing.