How to build better AI apps in React with MediaPipe’s latest APIs

MediaPipe has been around for a while. Google originally released it as a framework for running smaller on-device models in the browser and on mobile, mostly focused on vision tasks like face detection, hand tracking, pose estimation, etc. It now operates as Google’s open-source machine learning framework, built with TensorFlow andspecializing in helping devs create robust, on-device AI applications for real-time, static, and streaming media across different platforms.

The most recent release enables Vision Models to run fully on-device across platforms, without needing to run models server-side.

In this article, we will explore MediaPipe’s latest APIs while building an object detection and categorization application in React. We will specifically focus on the MediaPipe Tasks API for object detection.

Here’s what our final app will look like:

Before moving forward, you should have the following:

• React knowledge (Hooks, components)
• Node.js and npm installed
• A webcam (optional, but required for real-time testing)

Object detection has real-world applications across a wide range of industries. Developers building apps for retail, logistics, accessibility, smart homes, fitness, or security often need to detect and identify real-world items in images or video streams.

For example, an e-commerce app could let users scan products with their camera to auto-fill search queries.

In health and fitness, apps can use object detection to recognize body positions, equipment, or form during workouts.

For scientific research, an AI-driven science app could identify lab tools or specimens through a webcam.

By learning how to integrate object detection into a React app, developers can create smarter, more intuitive interfaces powered by computer vision, all running efficiently in the browser.

MediaPipe is one of Google’s most impressive contributions to real-time, on-device AI. The release of the MediaPipe Tasks API makes it possible to add real-time vision models into your web app with a few lines of JavaScript.

MediaPipe’s latest APIs, or MediaPipe Solutions suite, consist of the following:

MediaPipe Tasks

This offers a simple, cross-platform API for installing typical ML solutions with as little code as possible. It supports gesture recognition and image classification.

MediaPipe Model Maker

This simplifies the customization of pre-trained MediaPipe models using your data.

It makes it possible to fine-tune pre-existing models using comparatively small datasets.

MediaPipe Studio

This provides a no-code approach to exploring MediaPipe solutions with your data.

We will be using MediaPipe’s Tasks for object detection in our tutorial.

Project setup

I used Vite to initialize our app. For this project, I will be using Tailwind CSS with React.

To start, open your terminal and navigate to the desired folder where you want your code to be.

Then run the following command:

npm create vite@latest project_name 

Choose JavaScript as your preferred language.

Next, CD into your project directory or folder and then enter this:

npm install tailwindcss @tailwindcss/vite

Open the folder in VS Code or any other text editor you choose.

Next, modify the vite.config.js file and paste in the following code:

import { defineConfig } from "vite";
import react from "@vitejs/plugin-react";
import tailwindcss from "@tailwindcss/vite";

export default defineConfig({
  plugins: [react(), tailwindcss()],
});

Remove all code from the index.css file and paste this:

@import "tailwindcss";

Our React project is set up and ready. Let’s get into installing the required dependencies.

Install the required dependency

We need to install the MediaPipe Tasks Vision package for this project.

Navigate to your project directory and run:

npm i @mediapipe/tasks-vision

If the installation was successful, you will see a screen similar to the one below:

Getting started

To get started, we are going to create 3 folders for our project:

This is what our UI will look like:

Setting up our utility functions

We will create four utility functions inside the “utils” folder, each building upon another.

• drawDetections.js
• initializeObjectDetector.js
• detectObjectsAndDraw.js
• cleanupMediaPipeResources.js

In the “utils” folder, create a drawDetections.js file and paste the following:

// drawDetections.js

export const drawDetections = (context, detections) => {
  detections.forEach(detection => {
    const bbox = detection.boundingBox;
    const category = detection.categories[0]; 
    context.strokeStyle="red"; 
    context.lineWidth = 2;      
    context.strokeRect(bbox.originX, bbox.originY, bbox.width, bbox.height);        
    context.fillStyle="red";   
    context.font="16px Arial"; 
    const text = `${category.categoryName} (${(category.score * 100).toFixed(2)}%)`;
    const textX = bbox.originX;
    const textY = bbox.originY > 10 ? bbox.originY - 5 : 10;
    context.fillText(text, textX, textY);
  });
};

The drawDetections.js function is responsible for visualizing the detected objects on the HTML canvas.

It takes the 2D rendering context of the canvas and the MediaPipe detection results as input. For each detected object, it draws a colored box and a text label on the canvas.

Next, create an initializeObjectDetector.js file and populate it with the code below:

// initializeObjectDetector.js
import { ObjectDetector, FilesetResolver } from '@mediapipe/tasks-vision';

export const initializeObjectDetector = async (modelPath, scoreThreshold, maxResults) => {
  const visionFilesetResolver = await FilesetResolver.forVisionTasks(
    ''
  );
  const objectDetector = await ObjectDetector.createFromOptions(
    visionFilesetResolver, 
    {
      baseOptions: {
        modelAssetPath: modelPath,
      },
      runningMode: 'LIVE_STREAM', 
      scoreThreshold: scoreThreshold, 
      maxResults: maxResults,        
    }
  );


  return objectDetector; 
};

The initializeObjectDetector function calls on FilesetResolver.forVisionTasks() to load the WebAssembly(WASM) files. Then, it utilizes ObjectDetector.createFromOptions() to combine the loaded files with our AI model and the specified options, returning the ObjectDetector instance.

Next, we will create a detectObjectsAndDraw function.

This function accepts the following props:

• videoElement
• canvasElement
• objectDetector
• setDetectionsCallback

We’ll create the videoElement and the setDetectionsCallback state in the next section:

//detectObjectsAndDraw.js
import { drawDetections } from "./drawDetections";

export const detectObjectsAndDraw = (
  videoElement,
  canvasElement,
  objectDetector,
  setDetectionsCallback
) => {
  const context = canvasElement.getContext("2d");

  canvasElement.width = videoElement.videoWidth;
  canvasElement.height = videoElement.videoHeight;
  context.clearRect(0, 0, canvasElement.width, canvasElement.height);
  context.drawImage(
    videoElement,
    0,
    0,
    canvasElement.width,
    canvasElement.height
  );

  try {
    const detectionsResult = objectDetector.detectForVideo(
      videoElement,
      performance.now()
    );
    setDetectionsCallback(detectionsResult.detections);
    drawDetections(
      context,
      detectionsResult.detections,
      canvasElement.width,
      canvasElement.height
    );



  } catch (err) {
    console.error("Error during object detection or drawing:", err);
    setDetectionsCallback([]);
    return [];
  }
};

The detectObjectsAndDraw function draws the current video frame onto the canvas. It then runs the objectDetector on this frame to identify objects.

After that, it updates the setDetectionsCallback state with the detected objects.

It finally calls the drawDetections utility to overlay bounding boxes and labels on the canvas.

For this section, we will finally create the cleanupMediaPipeResources.js:

//cleanupMediaPipeResources.js
export const cleanupMediaPipeResources = ({ animationFrameId, videoRef, objectDetectorRef }) => {
  if (animationFrameId.current) {
    cancelAnimationFrame(animationFrameId.current);
    animationFrameId.current = null; 
  }



  if (videoRef.current && videoRef.current.srcObject) {
    videoRef.current.srcObject.getTracks().forEach(track => {
      track.stop(); 
    });
    videoRef.current.srcObject = null;
  }
  if (objectDetectorRef.current) {
    objectDetectorRef.current.close();
    objectDetectorRef.current = null; 
  }
};

The cleanupMediaPipeResources.js manages system resources after running our application.

It is responsible for stopping the animation frame loop, releasing the webcam stream, and closing the MediaPipe detector instance to prevent memory leaks and release hardware resources.

In the next section, we will set up our MediaPipe logic.

Getting the logic together

First, create a useMediaPipeObjectDetection.js file in the “hooks” folder.

Then import useEffect, useRef, useState, and useCallback like so:

import { useEffect, useRef, useState, useCallback } from 'react';
import { detectObjectsAndDraw } from '../utils/detectObjectsAndDraw';

I have also imported detectObjectsAndDraw which we created earlier.

These are the stages our code will follow:

1. Perform detection loop
2. Start Webcam
3. Initialize Detector
4. Initialization on mount and unmount

Perform detection loop

Below is our performDetectionLoop function, together with the supporting useRefs and useState we need for it to work:

 const videoRef = useRef(null);
  const canvasRef = useRef(null);
  const objectDetectorRef = useRef(null);
  const animationFrameId = useRef(null);

 const [detections, setDetections] = useState([]);

  const performDetectionLoop = useCallback(() => {
    if (!videoRef.current || !canvasRef.current || !objectDetectorRef.current) {
      animationFrameId.current = requestAnimationFrame(performDetectionLoop);
      return;
    }
    const video = videoRef.current;
    const canvas = canvasRef.current;
    const detector = objectDetectorRef.current;
    if (video.videoWidth === 0 || video.videoHeight === 0) {
      animationFrameId.current = requestAnimationFrame(performDetectionLoop);
      return;
    }
    detectObjectsAndDraw(video, canvas, detector, setDetections);
    animationFrameId.current = requestAnimationFrame(performDetectionLoop);
  }, [setDetections]);

The performDetectionLoop function checks if video, canvas, and detector are ready.

When they‘re ready, it calls the detectObjectsAndDraw utility function to process the current video frame. It finally updates the detection state through a callback from the detectObjectsAndDraw function.

Your useMediaPipeObjectDetection.js should now look like this:

import { useEffect, useRef, useState, useCallback } from 'react';
import { detectObjectsAndDraw } from '../utils/detectObjectsAndDraw';

const useMediaPipeObjectDetection = () => {

 const videoRef = useRef(null);
  const canvasRef = useRef(null);
  const objectDetectorRef = useRef(null);
  const animationFrameId = useRef(null);

 const [detections, setDetections] = useState([]);

  const performDetectionLoop = useCallback(() => {
    if (!videoRef.current || !canvasRef.current || !objectDetectorRef.current) {
      animationFrameId.current = requestAnimationFrame(performDetectionLoop);
      return;
    }
    const video = videoRef.current;
    const canvas = canvasRef.current;
    const detector = objectDetectorRef.current;
    if (video.videoWidth === 0 || video.videoHeight === 0) {
      animationFrameId.current = requestAnimationFrame(performDetectionLoop);
      return;
    }
    detectObjectsAndDraw(video, canvas, detector, setDetections);
    animationFrameId.current = requestAnimationFrame(performDetectionLoop);
  }, [setDetections]);    
};

export default useMediaPipeObjectDetection;

Start Webcam

The startWebcam code is below:

 //Start Webcam Function
  const startWebcam = useCallback(async () => {
    if (loading || error) return;

    try {
      const stream = await navigator.mediaDevices.getUserMedia({ video: true });

      if (videoRef.current) {
        videoRef.current.srcObject = stream;

        videoRef.current.onloadedmetadata = () => {
          videoRef.current.play();
          animationFrameId.current =
            requestAnimationFrame(performDetectionLoop);
        };
      }
    } catch (err) {
      console.error("Error accessing webcam:", err);
      setError(err);
    }
  }, [loading, error, performDetectionLoop]);

We also created two states for the startWebcam function:

const [loading, setLoading] = useState(true); 
const [error, setError] = useState(null); 

In startWebcam function, we made an asynchronous call asking the user’s browser for permission to access their webcam.

If permission is granted, we get the live feed from the camera. We then use the videoRef Hook to get a direct reference to the HTML element. Once we have the MediaStream, we assign it to the srcObject property of the video element, videoRef.current.srcObject = stream. This tells the video element to display the live camera feed.

We use the onloadedmetadata event to listen for when metadata is loaded so that we can play the video

We then use the videoRef.current.play() to start the video playback.

Once the video starts playing and its metadata is available, we start our continuous object detection process.

We do this by calling requestAnimationFrame, passing in the performDetectionLoop function.

Initialize Detector

initializeDetector uses the useCallback Hook to call the initializeObjectDetector function we created in our“utils” folder.

We first have to import the function from the “utils” folder:

import { initializeObjectDetector } from "../utils/initializeObjectDetector";

Next, copy the code below into your useMediaPipeObjectDetection.js file:

//InitializeDetector Function
  const initializeDetector = useCallback(async () => {
    try {
      setLoading(true);
      setError(null);
      const detector = await initializeObjectDetector(
        modelPath,
        scoreThreshold,
        maxResults
      );
      objectDetectorRef.current = detector;
      setLoading(false);
      console.log("Object Detector initialized!");
    } catch (err) {
      console.error("Failed to initialize Object Detector:", err);
      setError(err);
      setLoading(false);
    }
  }, [modelPath, scoreThreshold, maxResults]);

Next, we have two useEffects that get triggered when components mount and unmount.

The second useEffect Hook calls on the cleanupMediaPipeResources function we created earlier.

We will need to import the cleanupMediaPipeResources function.

First, import it like so:

import { cleanupMediaPipeResources } from "../utils/cleanupMediaPipeResources";

Then copy and paste the code below:

 //Effects
  useEffect(() => {
    initializeDetector();
  }, [initializeDetector]);

  useEffect(() => {
    return () => {
      cleanupMediaPipeResources({
        animationFrameId,
        videoRef,
        objectDetectorRef,
      });
    };
  }, []);

Our completed useMediaPipeObjectDetection.js file now looks like this:

// useMediaPipeObjectDetection.js

import { useEffect, useRef, useState, useCallback } from "react";
import { detectObjectsAndDraw } from "../utils/detectObjectsAndDraw";
import { initializeObjectDetector } from "../utils/initializeObjectDetector";
import { cleanupMediaPipeResources } from "../utils/cleanupMediaPipeResources";

const useMediaPipeObjectDetection = (
  modelPath,
  scoreThreshold = 0.5,
  maxResults = 5
) => {
  const videoRef = useRef(null);
  const canvasRef = useRef(null);
  const objectDetectorRef = useRef(null);
  const animationFrameId = useRef(null);

  const [detections, setDetections] = useState([]);
  const [loading, setLoading] = useState(true);
  const [error, setError] = useState(null);

  // Core Detection Loop Logic
  const performDetectionLoop = useCallback(() => {
    if (!videoRef.current || !canvasRef.current || !objectDetectorRef.current) {
      animationFrameId.current = requestAnimationFrame(performDetectionLoop);
      return;
    }
    const video = videoRef.current;
    const canvas = canvasRef.current;
    const detector = objectDetectorRef.current;
    if (video.videoWidth === 0 || video.videoHeight === 0) {
      animationFrameId.current = requestAnimationFrame(performDetectionLoop);
      return;
    }
    detectObjectsAndDraw(video, canvas, detector, setDetections);
    animationFrameId.current = requestAnimationFrame(performDetectionLoop);
  }, [setDetections]);

  //Start Webcam Function
  const startWebcam = useCallback(async () => {
    if (loading || error) return;

    try {
      const stream = await navigator.mediaDevices.getUserMedia({ video: true });

      if (videoRef.current) {
        videoRef.current.srcObject = stream;

        videoRef.current.onloadedmetadata = () => {
          videoRef.current.play();
          animationFrameId.current =
            requestAnimationFrame(performDetectionLoop);
        };
      }
    } catch (err) {
      console.error("Error accessing webcam:", err);
      setError(err);
    }
  }, [loading, error, performDetectionLoop]);

  //InitializeDetector Function

  const initializeDetector = useCallback(async () => {
    try {
      setLoading(true);
      setError(null);
      const detector = await initializeObjectDetector(
        modelPath,
        scoreThreshold,
        maxResults
      );
      objectDetectorRef.current = detector;
      setLoading(false);
      console.log("Object Detector initialized!");
    } catch (err) {
      console.error("Failed to initialize Object Detector:", err);
      setError(err);
      setLoading(false);
    }
  }, [modelPath, scoreThreshold, maxResults]);

  //Effects for Lifecycle Management
  useEffect(() => {
    initializeDetector();
  }, [initializeDetector]);

  useEffect(() => {
    return () => {
      cleanupMediaPipeResources({
        animationFrameId,
        videoRef,
        objectDetectorRef,
      });
    };
  }, []);
  return { videoRef, canvasRef, detections, loading, error, startWebcam };
};

export default useMediaPipeObjectDetection;

Next, we will work on our app’s user interface.

Building the UI

In this section, we will build out our UI components. We have 4 UI components in total:

• VideoCanvasDisplay
• DetectionResults
• ObjectDetectionApp
• App

In our UI setup, the ObjectDetectionApp renders VideoCanvasDisplay and DetectionResults.

The ObjectDetectionApp component then gets rendered in the App.jsx file like so:

import React from "react";
import ObjectDetectionApp from "./components/ObjectDetectionApp";

function App() {


  const MODEL_PATH =
    "";

  return (
    
  );
}

export default App;

To make for easy change, we passed in the MODEL_PATH, or the model URL as props to the ObjectDetectionApp.

Navigate inside the “components” folder and create the VideoCanvasDisplay.jsx file.

Then copy and paste the code below:

// VideoCanvasDisplay.jsx
import React from "react";

const VideoCanvasDisplay = ({ videoRef, canvasRef }) => {
  return (
    
  );
};

export default VideoCanvasDisplay;

The component displays video output from the webcam and the HTML canvas on top of the video with some Tailwind CSS styling.

Next is the DetectionResults component. As the name suggests, it displays the object detection results:

// DetectionResults.jsx
import React from 'react';
const DetectionResults = ({ detections }) => {
  return (
    

      
Detected Objects
      {detections.length > 0 ? (
        

          {detections.map((detection, index) => (
            

              {detection.categories[0].categoryName} (Score:{' '}
              {(detection.categories[0].score * 100).toFixed(2)}%)
            
          ))}
        
      ) : (
        
No objects detected yet. Start the webcam.
      )}
    
  );
};

export default DetectionResults;

Finally, there is the ObjectDetectionApp component, which renders the VideoCanvasDisplay and DetectionResultscomponents:

import React from "react";
import useMediaPipeObjectDetection from "../hooks/useMediaPipeObjectDetection";
import VideoCanvasDisplay from "../components/VideoCanvasDisplay";
import DetectionResults from "../components/DetectionResults";

const ObjectDetectionApp = ({ modelPath }) => {
  const { videoRef, canvasRef, detections, loading, error, startWebcam } =
    useMediaPipeObjectDetection(modelPath);

  return (
    

      

        

          

            

              {loading && !error && (
                

                  Loading MediaPipe model...
                
              )}
              {error && (
                

                  

                    Error:{" "}
                    {error.message || "Failed to initialize object detector."}
                  
                  

                    Please ensure your webcam is accessible
                  
                
              )}

              {!loading && !error && (
                <>
                  

                    
                      Search with camera
                    
                  

                  
                  
                >
              )}
            
          
        
      
    
  );
};

export default ObjectDetectionApp;

Now we have all of the pieces together.

Let’s now run our app and see how it works

Start the app with npm run dev :

Notice how the object detection happens in real-time.

Here is the code repository for the final build.

Conclusion

Google MediaPipe provides a way to run object detection right inside the browser and without needing to set up a backend for it or train data for it.

In this tutorial, we covered a brief introduction to the new Mediapipe APIs (MediaPipe Tasks, MediaPipe Model Maker, and MediaPipe Studio. We then set up an object detection app using MediaPipe. We used the React getUserMedia method to get the user’s camera feed, which we fed to the MediaPipe object detector model.

We then nicely showed in real-time the results of the object detection on the screen.