Web -based development platforms such as Repl.it, JSFIDDLEAnd Code and box has made it possible to write, compile, and run the code directly in the browser.

For companies, startups, and educational platforms, creating special compilers can be an innovative way to increase collaboration, training, and user involvement.

On this blog, we will guide you in a way Build an online code compiler Using react.js for frontend and node.js for backend, including everything from architecture to security considerations for the production environment.

What is an online code compiler?

Online code compiler is a web -based tool That allows users to write, compile, and run the code without installing software locally. Modern compilers often support various languages such as Javascript, Python, Java, and C ++.

The main features include:

• Syntax syntax and autocomplete for faster coding

• Multi-language support for various development needs

• Execution of Time Code with Instant Output

• A safe sand box environment to prevent bad activities

When you are Build an online code compilerYou can adjust its function to suit your organization’s needs – whether it is a learning platform, company testing tool, or an interactive demo environment.

Project Scope: What will we build

Examples of our project will be an online code compiler that focuses on javascript with:

1. Fretend editor Using a monaco editor for syntactic syntax

2. Backend fire to accept, run, and restore code output

3. Safe execution using node.js child_prosess

4. (Optional) Docker integration for multi-language execution and isolation

Pile of technology

Component	Technology used
Frontend	React.js, Monaco Editor
Backend	Node.js, Express.js
Code execution	Child_ProSess node module
Optional	Docker (Security), Mongodb (Code Storage)

Project structure

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Online-code-compiler/
├── Clients/ # react frontend
├── Server/ # node backend

Step 1: Prepare the Frontend React

1. Create the Frontend application:

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NPM Create Vite@Latest Clients – – Template React
CD client

2. Install Monaco Editor and Axios:

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Npm install @monaco-editor/react axios

3. UI editor at SRC/APP.JS:

Javascript

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Imports react, {usestate} from “react”;
Import editor from “@monaco-editor/react”;
Axios imports from “axios”;

Function App () {
Const [code, setCode] = Usestate (“// Write your code here”);
Const [output, setOutput] = Usestate (“”);

Const Runcode = ASYNC () => {
Const response = waiting for axios.post (“{code});
setoutput (response.data.output);
};

return (

);
}

Default Export Application;

Step 2: Building backend node.js

1. Create a backend folder:

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server mkdir && cd server
NPM INIT -Y
NPM Install Express Cors Body-Parser

2. Implementing the execution of the code on server/index.js:

Javascript

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Const Express = requires (“express”);
Const Cors = need (“CORS”);
const {exec} = requires (“child_process”);
Const Bodyparser = requires (“Body-Parser”);
const fs = need (“fs”);

Const App = Express ();
App.use (Cors ());
app.use (bodyparser.json ());

app.post (“/run”, (Req, Res) => {
const {code} = Req.body;
fs.writefilesync (“temp.js”, code);

exec (“node temp.js”, (error, stdout, stationr) => {
if (error) {
res.send ({output: stationr});
} if not {
res.send ({output: stdout});
}
});
});

App. Listen (5000, () => {
Console.log (“server runs at http: // localhost: 5000”);
});

Step 3: Connect Frontend and Backend

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NPM Run Dev

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Node Index.js

• Test by writing the code in the editor and clicking Run to see output in real-time.

Security considerations when you build an online code compiler

Run the code made by risk users. In production:

• Use a docker container for an isolated execution environment

• Enforce the time limit to stop unlimited loop

• Validating and cleaning input before execution

• Apply tariff restrictions to prevent abuse

Conclusion

When you are Build an online code compilerYou create more than just a tool to activate the collaboration of real-time coding, improve learning experiences, and increase productivity for developers.

With react.js for frontend and node.js for backend, you can make a solution ready to scalable, safe, and ready for companies that are tailored to your business needs.

Additional resources: