💻 Create Your Own LeetCode with Judge🔥
What is Judge0?
Judge0 is an open-source online code execution engine that supports over 60 programming languages. It allows you to compile and run code remotely via a REST API, making it perfect for building coding platforms, online judges, or interview preparation tools like LeetCode, HackerRank, or Codeforces. Whether you're running C++, Python, JavaScript, or Go — Judge0 handles it all in a secure, sandboxed environment.
How to Setup Judge0?
I recommend using Linux especially Ubuntu-20.04, but you can also setup this on Mac.
For Windows Users Special Steps
Install WSL in your Windows, run this command in your PowerShell terminal:
Installing WSL
wsl --install
Then setup your Unix username and password. After this restart your PC then run this command to install Ubuntu-20.04:
wsl --install -d Ubuntu-20.04
Then login to Ubuntu with this command:
wsl -d Ubuntu-20.04
Your terminal will change like this:
Then run command:
sudo apt update
# Enter the password which you set in the Unix login
After this:
sudo apt upgrade
sudo reboot
After rebooting the Ubuntu it will be closed so then restart with:
wsl -d Ubuntu-20.04
Then again it will be like this:
Then run again:
sudo apt update
# Enter the password
Then open the grub file in nano with command:
✅ Fixing GRUB Syntax Error in Ubuntu
🔧 Step 1: Open the GRUB config file
sudo nano /etc/default/grub
It'll ask for your password — type it and press
Enter.
🧾 Step 2: Paste the following into the file
Note: (if you have empty grub file then do this if not paste only last line):
GRUB_DEFAULT=0
GRUB_TIMEOUT=10
GRUB_DISTRIBUTOR=`lsb_release -i -s 2> /dev/null || echo Debian`
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"
GRUB_CMDLINE_LINUX=systemd.unified_cgroup_hierarchy=0
- Use
Ctrl + Shift + Vto paste (if you're on a standard terminal). - Make sure there are no extra characters or spaces after any line.
💾 Step 3: Save and Exit
- Press
Ctrl + O(to write/save the file) - Press
Enter(to confirm) - Press
Ctrl + X(to exit the editor)
🔄 Step 4: Update GRUB
sudo update-grub
📋 If a popup appears, select the 2nd option (usually your system disk), then press OK.
If no popup, it will just update silently — that's fine too.
✅ Step 5: Reconfigure and clean up
Run this to finish up:
sudo dpkg --configure -a
sudo apt install -f
This should fix the broken grub-pc and grub-gfxpayload-lists issues.
After this everything is on Judge0 GitHub documentation link: https://github.com/judge0/judge0/blob/master/CHANGELOG.md
But here's simple steps to do it:
Download Docker and Docker-compose with this command:
sudo apt install docker
# This will install Docker
sudo apt install docker-compose
# This will install Docker-compose
Getting Judge0 File
Note: Mac users can follow this from here
wget https://github.com/judge0/judge0/releases/download/v1.13.1/judge0-v1.13.1.zip
Installing Unzip
sudo apt install unzip
# This will install unzip
Unzip the Judge0 file
unzip judge0-v1.13.1.zip
Setting Up Password
Then go to Judge0 file with cd command:
cd judge0-v1.13.1/
ls
# ls will show you these files docker-compose.yml judge0.conf
Then set the REDIS_PASSWORD and POSTGRES_PASSWORD and judge0.conf of your choice.
I recommend using this website to generate passwords.
sudo nano judge0.conf
# Then set the password
- Press
Ctrl + O(to write/save the file) - Press
Enter(to confirm) - Press
Ctrl + X(to exit the editor)
Running DB and Docker
After lets run db and redis this will take time:
sudo docker-compose up -d db redis
sleep 10s
sudo docker-compose up -d
sleep 5s
Then check if containers are running or not with command:
sudo docker-compose ps
# It will show the four status are up
Then go to http://localhost:2358/docs if it's open your setup done and you can go to http://localhost:2358/dummy-client.html to run the code.
For Restarting the Program
If you want to start the setup just run these command in Windows terminal:
# Mac and Linux users skip WSL command
wsl -d Ubuntu-20.04
sudo docker-compose up -d
# It will run everything again
Note: For Mac users if it's not working for Mac users simply setup a virtual box machine with Linux or purchase a machine online for more information follow instructions from Hitesh sir video https://youtu.be/6nkNUDNhSYI?si=OvVQuFpqN13PQ5kV
🎯 Conclusion
Now you have your own Judge0 setup running locally! You can build your own coding platform, create online judges, or develop interview preparation tools. The Judge0 API gives you the power to execute code in over 60 programming languages securely.
Happy coding! 🚀