Achieve Rapid Development: Combining React, Azure Functions, and Cosmos DB

In this tutorial, we will explore how to expedite your web development process by using the powerful combination of React, Azure Functions, and Cosmos DB. React helps in crafting a performant and scalable frontend with ease, Azure Functions provides serverless computing infrastructure, and Cosmos DB stores data globally to ensure optimal availability. Together, these technologies create a highly scalable full-stack application.


To follow this tutorial, you should have a basic understanding of React, JavaScript, and web development. In addition, you will need to set up an Azure account. Once you have these prerequisites in place, let's kick off with setting up our project.

Setting up the project

Firstly, let's create a React project using create-react-app. Open your terminal and run:

  npx create-react-app rapid-development
  cd rapid-development

You should now have a basic React application up and running. Next, we will set up Azure Functions for our serverless logic.

Setting up Azure Functions

To use Azure Functions, you need to install the Azure Functions Core Tools and Azure Functions for JavaScript. Run:

  npm install -g azure-functions-core-tools
  npm install azure-functions

Now, create a new folder called 'functions' at the root of your React project. Within this folder, create another folder called 'HttpTrigger'. Inside the 'HttpTrigger' folder, create a new file 'index.js' and enter the following code:

  module.exports = async function (context, req) {
    context.res = {
      body: "Hello from Azure Functions"

This simple Azure Function returns a greeting message. To test it locally, go to the 'functions' folder in the terminal and execute:

  func host start

Once the Azure Functions runtime initializes, visit http://localhost:7071/api/HttpTrigger in your browser to see the greeting message.

Integrating React with Azure Functions

Now, we need to connect our React application to our Azure Function. First, we must add a proxy to bypass CORS restrictions. Add this "proxy" configuration to your package.json file:

  "proxy": {
    "/api": {
      "target": "http://localhost:7071"

Next, let's modify our React component to display the greeting message from the Azure Function. In your 'App.js' file, replace the existing code with the following:

  import React, { useState, useEffect } from 'react';
  import './App.css';

  function App() {
    const [message, setMessage] = useState();

    useEffect(() => {
        .then(response => response.text())
        .then(text => setMessage(text));
    }, []);

    return (
      <div className="App">

  export default App;

Now run your React application with npm start and ensure the greeting message displays on the page.

Setting up Cosmos DB

For our global-scale database, we will use Azure Cosmos DB. Set up a new Cosmos DB instance on the Azure Portal. After creating the instance, collect the Connection String from the 'Keys' tab in your Cosmos DB account.

Connecting Azure Functions with Cosmos DB

Install the @azure/cosmos package and add your Cosmos DB connection string to the 'local.settings.json' file in your 'functions' folder:

  npm install @azure/cosmos

In 'local.settings.json':

    "Values": {
      "AzureWebJobsStorage": "",
      "CosmosDBConnection": "your-cosmos-db-connection-string"

Now you can leverage the powerful capabilities of Cosmos DB in your Azure Functions code. For example, you can insert, query, and update documents in your Cosmos DB instance seamlessly from your serverless functions.


With React, Azure Functions, and Cosmos DB, you can rapidly build full-stack applications that scale gracefully. Each technology contributes its unique strengths - React simplifies frontend development, Azure Functions offers serverless logic, and Cosmos DB supplies a globally-distributed database. Embrace this powerful combination to accelerate your web development journey and deliver top-tier products.