💻 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 --insall -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 passowrd 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 wll 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.

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🧾 Step 2: Paste the following into the file

Note:- (if you have empty grub file then do this if not paste only last line):

bashCopyEditGRUB_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 + V to paste (if you're on a standard terminal).

• Make sure there are no extra characters or spaces after any line.

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💾 Step 3: Save and Exit

• Press Ctrl + O (to write/save the file)

• Press Enter (to confirm)

• Press Ctrl + X (to exit the editor)

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🔄 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.

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✅ 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 docke-compose with this command

sudo apt install docker
// this will install docker
sudo apt install docker-compose
// this will install docker-compose

Geting 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 is 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_PASSWORDand 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 container 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 thing again

Note: For mac users if it’s not workging 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