This is a quick start guide to show you how to integrate ImageKit in a React application. The code samples covered here are hosted on Github: https://github.com/imagekit-samples/quickstart/tree/master/react.
This guide walks you through the following topics:
For this tutorial, it is recommended to create a dummy React app, as shown below.
Create a React app:
Let's use the create-react-app
CLI utility provided by React to build a new project:
npx create-react-app imagekit-react-app
Navigate to the project directory:
cd imagekit-react-app/
Open up the project in your text editor of choice, and navigate to src/App.js
. This is where we will do most of our work. It should look like this:
src/App.jsimport React from 'react';import logo from './logo.svg';import './App.css';function App() {return (<div className="App"><header className="App-header"><img src={logo} className="App-logo" alt="logo" /><p>Edit <code>src/App.js</code> and save to reload.</p><aclassName="App-link"href="https://reactjs.org"target="_blank"rel="noopener noreferrer">Learn React</a></header></div>);}export default App;
Now run the app:
npm start
In your web browser, navigate to http://localhost:3000/
You should see the dummy app created by React CLI. Now we can begin our work.
Install the ImageKit React SDK:
Installing the ImageKit React SDK in our app is pretty simple:
npm install --save imagekitio-react
Before the SDK can be used, let's learn about and obtain the requisite initialization parameters:
urlEndpoint
is a required parameter. This can be obtained from the URL-endpoint section or the developer section on your ImageKit dashboard.
publicKey
and authenticationEndpoint
parameters are optional and only needed if you want to use the SDK for client-side file upload. These can be obtained from the Developer section on your ImageKit dashboard.
// required parameter to fetch imagesconst urlEndpoint = '<YOUR_IMAGEKIT_URL_ENDPOINT>';// optional parameters (needed for client-side upload)const publicKey = '<YOUR_IMAGEKIT_PUBLIC_KEY>';const authenticationEndpoint = 'https://www.your-server.com/auth';
Note: Do not include your API private key in any client-side code, including this SDK or its initialization. If you pass the privateKey
parameter while initializing this SDK, it will throw an error.
ImageKit Components:
This SDK provides 3 components:
IKImage
for image rendering. The output is a <img>
tag.
IKUpload
for file uploading. The output is a <input type="file">
tag.
IKContext
for defining authentication context, i.e. urlEndpoint
, publicKey
and authenticationEndpoint
to all child elements.
You can import components individually:
import { IKImage, IKContext, IKUpload } from 'imagekitio-react';
Let's remove the existing dummy code in src/App.js
file, then add the urlEndpoint
:
src/App.jsimport React from 'react';import './App.css';const urlEndpoint = '<YOUR_IMAGEKIT_URL_ENDPOINT>';function App() {return (<div className="App"></div>);}export default App;
Loading image from relative path:
Remember the default image we mentioned earlier? It should be available at the following URL:
https://ik.imagekit.io/<YOUR_IMAGEKIT_ID>/default-image.jpg
Let's fetch and display it! For this, we will use the IKImage
component.
Import IKImage
from the SDK:
import { IKImage } from 'imagekitio-react';
Now let's add it to our App
. Along with the image path
prop, it also needs the prop for urlEndpoint
:
<IKImageurlEndpoint={urlEndpoint}path="default-image.jpg"/>
Rendered HTML element:
<img src="https://ik.imagekit.io/demo/default-image.jpg?ik-sdk-version=react-1.x.x" alt="">
The App.js
file should look like this now:
src/App.jsimport React from 'react';import './App.css';import { IKImage } from 'imagekitio-react';const urlEndpoint = '<YOUR_IMAGEKIT_URL_ENDPOINT>';function App() {return (<div className="App"><h1>ImageKit React quick start</h1><IKImageurlEndpoint={urlEndpoint}path="default-image.jpg"/></div>);}export default App;
Your React app should now display the default image in its full size:
You can pass styles and other attributes as props. For e.g. lets add 400px width by adding the width
prop:
<IKImageurlEndpoint={urlEndpoint}path="default-image.jpg"width="400"/>
This is how the output should look now:
Note that here we have set the width to 400px at the <img>
tag level only. Intrinsically, the fetched image is still 1000px wide.
Loading image from an absolute path:
If you have an absolute image path coming from the backend API e.g. https://www.custom-domain.com/default-image.jpg
then you can use src
prop to load the image.
For example:
<IKImageurlEndpoint={urlEndpoint}src="https://ik.imagekit.io/demo/default-image.jpg"width="400"/>
The output looks like this:
It is not necessary to specify the urlEndpoint
in every instance of IKImage
. This can be managed much more easily with the IKContext
component.
IKContext
is a wrapper that can be configured with your SDK initialization parameters. Pass your urlEndpoint
to it as a prop, and you're good to go!
Let's go ahead and import it within the App.js
file:
import { IKContext, IKImage } from 'imagekitio-react';
Now add the IKContext
component to the render function:
<IKContext urlEndpoint={urlEndpoint}></IKContext>
Let's nest our IKImage
components within it, so that those can access the urlEndpoint
from the context wrapper.
src/App.jsimport React from 'react';import './App.css';import { IKContext, IKImage } from 'imagekitio-react';const urlEndpoint = '<YOUR_IMAGEKIT_URL_ENDPOINT>';function App() {return (<div className="App"><IKContext urlEndpoint={urlEndpoint}><h1>ImageKit React quick start</h1><IKImage path="default-image.jpg" width="400" /><h2>Loading image from an absolute path</h2><IKImagesrc="https://ik.imagekit.io/demo/default-image.jpg"width="400"/></IKContext></div>);}export default App;
Let’s now learn how to manipulate images using transformations.
The React SDK gives a name to each transformation parameter, e.g. height
for h
and width
for w
parameter. It makes your code more readable. If the property does not match any of the available options, it is added as it is. See the full list of supported transformations in React SDK on Github.
You can also use h
and w
parameter instead of height
and width
.
See the complete list of transformations supported in ImageKit here.
To resize an image along with its height or width, we need to pass the transformation
object as a prop to IKImage
.
Let’s resize the default image to 200px height and width:
<IKImagepath="default-image.jpg"transformation={[{height: 200,width: 200}]}/>
Rendered HTML element:
<img src="https://ik.imagekit.io/<YOUR_IMAGEKIT_ID>/tr:h-200,w-200/default-image.jpg?ik-sdk-version=react-1.x.x"path="default-image.jpg"alt="">
Refresh your browser to get the resized image.
You can use the quality parameter to change image quality like this:
<IKImagepath="default-image.jpg"transformation={[{ quality: 10 }]}width="400"/>
Rendered HTML:
<img src="https://ik.imagekit.io/<YOUR_IMAGEKIT_ID>/tr:q-10/default-image.jpg?ik-sdk-version=react-1.x.x"path="default-image.jpg" width="400" alt="">
Let’s now see how cropping works. We will try the extract
crop strategy. In this strategy, instead of resizing the whole image, we extract out a region of the requested dimension from the original image. You can read more about this here.
<IKImagepath="default-image.jpg"transformation={[{height: 300,width: 200,cropMode: 'extract',}]}/>
Rendered HTML element:
<img src="https://ik.imagekit.io/<YOUR_IMAGEKIT_ID>/tr:h-300,w-200,cm-extract/default-image.jpg"path="default-image.jpg"alt="">
Chained transformations provide a simple way to control the sequence in which transformations are applied.
Let’s try it out by resizing an image, then rotating it:
<IKImagepath="default-image.jpg"transformation={[{height: 300,width: 200}]}/>
Transformation URL:
<img src="https://ik.imagekit.io/<YOUR_IMAGEKIT_ID>/tr:h-300,w-200/default-image.jpg"path="default-image.jpg"alt="">
Now, rotate the image by 90 degrees.
<IKImagepath="default-image.jpg"transformation={[{height: 300,width: 200,}, {rt: 90,}]}/>
Chained Transformation URL:
<img src="https://ik.imagekit.io/<YOUR_IMAGEKIT_ID>/tr:h-300,w-200:rt-90/default-image.jpg"path="default-image.jpg"alt="">
Let’s flip the order of transformation and see what happens.
<IKImagepath="default-image.jpg"transformation={[{rt: 90,}, {height: 300,width: 200,}]}/>
Chained Transformation URL:
<img src="https://ik.imagekit.io/<YOUR_IMAGEKIT_ID>/tr:rt-90:h-300,w-200/default-image.jpg"path="default-image.jpg"alt="">
ImageKit.io allows you to add text and image overlay dynamically.
For example, a text overlay can be used to superimpose text on an image. Try it like so:
<IKImagepath="default-image.jpg"transformation={[{height: 300,width: 300,overlayText: 'ImageKit',overlayTextFontSize: 50,overlayTextColor: '0651D5',}]}/>
Rendered HTML element:
<img src="https://ik.imagekit.io/<YOUR_IMAGEKIT_ID>/tr:h-300,w-300,ot-ImageKit,ots-50,otc-0651D5/default-image.jpg"path="default-image.jpg"alt="">
You can lazy load images using the loading
prop in IKImage
component. When you use loading="lazy"
, all images that are immediately viewable without scrolling load normally. Those that are far below the device viewport are only fetched when the user scrolls near them.
The SDK uses a fixed threshold based on the effective connection type to ensure that images are loaded early enough so that they have finished loading once the user scrolls near to them.
You should always set the height and width of the image element to avoid layout shift when lazy-loading images.
<IKImagepath="default-image.jpg"transformation={[{ height: 300, width: 400 }]}loading="lazy"height="300"width="400"/>
Rendered HTML element:
<img src="https://ik.imagekit.io/<YOUR_IMAGEKIT_ID>/tr:h-300,w-400/default-image.jpg?ik-sdk-version=react-1.x.x"path="default-image.jpg" loading="lazy" height="300" width="400" alt="">
To improve user experience, you can use a low-quality blurred variant of the original image as a placeholder while the original image is being loaded in the background. Once the loading of the original image is finished, the placeholder is replaced with the original image.
// Loading a blurred low quality image placeholder// while the original image is being loaded<IKImagepath="default-image.jpg"lqip={{ active: true, quality: 20 }}width="400"/>
You have the option to lazy-load the original image only when the user scrolls near them. Until then, only a low-quality placeholder is loaded. This saves a lot of network bandwidth if the user never scrolls further down.
// Loading a blurred low quality image placeholder// and lazy-loading original when user scrolls near them<IKImagepath="default-image.jpg"transformation={[{ height:300, width:400 }]}lqip={{ active:true }}loading="lazy"height="300"width="400"/>
Let's now learn how to upload an image to our media library.
React SDK provides IKUpload
component which renders an input type="file"
tag that you can use to upload files to the ImageKit media library directly from the client-side.
To implement this functionality, a backend server is needed to authenticate the request using your API private key.
For this quickstart guide, we will create a sample Node.js server which will provide an authentication endpoint at http://localhost:3001/auth
.
Let's create a file index.js
inside server
folder in the project root.
mkdir servertouch server/index.js
Install the basic packages needed to create a dummy server for ImageKit backend authentication:
npm install --save express imagekit
We will use the ImageKit Node.js SDK to implement http://localhost:3001/auth
.
The backend SDK requires your API public key, private key, and URL endpoint. You can obtain them from Developer Options and URL-endpoint pages respectively.
This is how server/index.js
file should look now. Replace <YOUR_IMAGEKIT_URL_ENDPOINT>
, <YOUR_IMAGEKIT_PUBLIC_KEY>
and <YOUR_IMAGEKIT_PRIVATE_KEY>
with actual values:
server/index.js/*This is our backend server.Replace YOUR_IMAGEKIT_URL_ENDPOINT, YOUR_IMAGEKIT_PUBLIC_KEY,and YOUR_IMAGEKIT_PRIVATE_KEY with actual values*/const express = require('express');const app = express();const ImageKit = require('imagekit');const imagekit = new ImageKit({urlEndpoint: '<YOUR_IMAGEKIT_URL_ENDPOINT>',publicKey: '<YOUR_IMAGEKIT_PUBLIC_KEY>',privateKey: '<YOUR_IMAGEKIT_PRIVATE_KEY>'});// allow cross-origin requestsapp.use(function(req, res, next) {res.header("Access-Control-Allow-Origin", "*");res.header("Access-Control-Allow-Headers","Origin, X-Requested-With, Content-Type, Accept");next();});app.get('/auth', function (req, res) {var result = imagekit.getAuthenticationParameters();res.send(result);});app.listen(3001, function () {console.log('Live at Port 3001');});
authenticationEndpoint
should be implemented in your backend. The SDK makes an HTTP GET request to this endpoint and expects a JSON response with three fields i.e. signature
, token
, and expire
. Learn how to implement authenticationEndpoint on your server.
Let's run the backend server.
cd servernode index.js
You should see a log saying that the app is “Live on port 3001”.
If you GET http://localhost:3001/auth
, you should see a JSON response like this. Actual values will vary.
{token: "5dd0e211-8d67-452e-9acd-954c0bd53a1f",expire: 1601047259,signature: "dcb8e72e2b6e98186ec56c62c9e62886f40eaa96"}
Now that we have our authentication server up and running, let's configure the publicKey
and authenticationEndpoint
in the frontend React app:
Add the following to src/App.js
file to initialize the SDK with auth params:
const publicKey = '<YOUR_IMAGEKIT_PUBLIC_KEY>';const authenticationEndpoint = 'http://localhost:3001/auth';
Now, pass these values as props into a new IKContext
instance which will hold our upload component:
<IKContext publicKey={publicKey} urlEndpoint={urlEndpoint} authenticationEndpoint={authenticationEndpoint} >{/* ...child components */}</IKContext>
This is how src/App.js
should look now. Replace <YOUR_IMAGEKIT_URL_ENDPOINT>
and <YOUR_IMAGEKIT_PUBLIC_KEY>
with actual values:
src/App.jsimport React from 'react';import './App.css';import { IKContext, IKImage } from 'imagekitio-react';const urlEndpoint = '<YOUR_IMAGEKIT_URL_ENDPOINT>';const publicKey = '<YOUR_IMAGEKIT_PUBLIC_KEY>';const authenticationEndpoint = 'http://localhost:3001/auth';function App() {return (<div className="App"><IKContexturlEndpoint={urlEndpoint}publicKey={publicKey}authenticationEndpoint={authenticationEndpoint}>{/* ...client side upload component goes here */}</IKContext>{/* ...other SDK components added previously */}</div>);}export default App;
For this, we will use the IKUpload
component. Let's import it from the SDK into our App.js
file:
import { IKContext, IKImage, IKUpload } from 'imagekitio-react';
Add the IKUpload
component nested within IKContext
, as well as a couple of event handlers for upload error and success, onError
and onSuccess
respectively:
src/App.jsimport React from 'react';import './App.css';import { IKContext, IKImage, IKUpload } from 'imagekitio-react';const publicKey = '<YOUR_IMAGEKIT_PUBLIC_KEY>';const urlEndpoint = '<YOUR_IMAGEKIT_URL_ENDPOINT>';const authenticationEndpoint = 'http://localhost:3001/auth';const onError = err => {console.log("Error", err);};const onSuccess = res => {console.log("Success", res);};function App() {return (<div className="App"><h1>ImageKit React quick start</h1><IKContextpublicKey={publicKey}urlEndpoint={urlEndpoint}authenticationEndpoint={authenticationEndpoint}><p>Upload an image</p><IKUploadfileName="test-upload.png"onError={onError}onSuccess={onSuccess}/></IKContext>{/* ...other SDK components added previously */}</div>);}export default App;
This is how it looks in the UI:
Direct file uploading from the browser
Let’s now upload an image by selecting a file from the file input.
When you choose a file, the file is immediately uploaded. You can pass optional onSuccess
and onError
callback functions as props like we have.
You can verify that file was successfully uploaded by checking the browser console. In case of success, it should print a success message, like this:
The response object would look similar to this (values may vary):
{fileId: "5f7d39aa80da9a54b1d7976a",filePath: "/test-upload_0GfSgMm4p.png",fileType: "image",height: 298,name: "test-upload_0GfSgMm4p.png",size: 5748,thumbnailUrl: "https://ik.imagekit.io/<YOUR_IMAGEKIT_ID>/tr:n-media_library_thumbnail/test-upload_0GfSgMm4p.png",url: "https://ik.imagekit.io/<YOUR_IMAGEKIT_ID>/test-upload_0GfSgMm4p.png",width: 298,}
After a successful upload, you should see the newly uploaded image in the Media Library section of your ImageKit dashboard.
If you don't see the image, check if there are any errors in the browser console log. Then verify whether the API private key has been configured correctly in the server app and if the server app is running.
Fetching uploaded file
Fetch uploaded image and show in UI using IKImage
with the filePath
returned in the upload response.
<IKImage path="/test-upload_0GfSgMm4p.png" />
The app should display your uploaded image correctly!
We strongly recommend using Error Boundaries to handle errors in the React UI. ErrorBoundary
is used to gracefully handle errors anywhere in the child component tree of a React app.
It can be used to log errors and display a fallback UI instead of the component tree that crashed.
<ErrorBoundary><IKImage publicKey={publicKey} urlEndpoint={urlEndpoint} path={path}transformation={[{height: 300,width: 400}]}/></ErrorBoundary>
The possibilities for image manipulation and optimization with ImageKit are endless. Learn more about it here: