www.rembg.com API wrapper for Node.js

A simple, FREE AI background removal tool for Node.js. Currently, this is THE ONLY FREE library available for personal usage from API. Check out our website at www.rembg.com for more details.

🚨 Minimum Node.js Version 🚨

To use @remove-background-ai/rembg.js, you must have Node.js v18.17.0 or higher installed.

⚠️ WARNING: Node.js v18 is already out of support. It's strongly recommended to use at least Node.js v20 or higher for better security, performance, and long-term support.

Requirements

Get your FREE API Key from the https://www.rembg.com/api-usage PS: you can still use the API Keys without key but it is very limited

Installation

npm i --save @remove-background-ai/rembg.js

API reference

Parameter	Type(s)	Required	Default	Notes
apiKey	string	✔︎	—	Rembg API key (free tier available).
inputImage	string Buffer { base64: string }	✔︎	—	Image path, buffer or base-64 wrapper. (npm)
onDownloadProgress	(AxiosProgressEvent)=>void	–	—	Called repeatedly while result is streamed. (npm)
onUploadProgress	(AxiosProgressEvent)=>void	–	—	Called repeatedly while upload is streamed. (npm)
options.format	webp (default) png	–	webp	Encoding format, by default server returns WEBP image.
options.returnBase64	boolean	–	false	Return base-64 instead of temp file. (npm)
options.returnMask	boolean	–	false	Return alpha-mask image only. (npm)
options.w	number	–	—	Target width (keeps aspect). (npm)
options.h	number	–	—	Target height (keeps aspect). (npm)
options.exact_resize	boolean	–	false	Force exact w × h (can distort). (npm)
options.angle	number	–	—	Rotation angle in degrees. (npm)
options.expand	boolean	–	true	Add padding so rotated images aren't cropped. (npm)
options.bg_color	string	–	—	Optional solid background color in hex (e.g. #FFFFFFFF) or named color (e.g. "red", "blue"). (npm)

Library

inputImage can be one of these: string | Buffer | { base64: string };

// script.mjs file

import  { rembg } from '@remove-background-ai/rembg.js';
import dotenv from 'dotenv';
// Load environment variables from .env file
dotenv.config();

// API_KEY will be loaded from the .env file
const API_KEY = process.env.API_KEY;

// log upload and download progress
const onDownloadProgress = console.log;
const onUploadProgress = console.log;

rembg({
    apiKey: API_KEY,
    inputImage: './input.png',
    onDownloadProgress,
    onUploadProgress
}).then(({ outputImagePath, cleanup }) => {
    console.log(`✅🎉 background removed and saved under path=${outputImagePath}`);
    // if called, it will cleanup (remove from disk) your removed background image
    // cleanup();
});

Base64 return type example

if you wish to return a Base64 instead of temporary URL you can use retrunBase64 parameter:

import { rembg } from '../dist/index.js';
import dotenv from 'dotenv';
// Load environment variables from .env file
dotenv.config();

// API_KEY will be loaded from the .env file
const API_KEY = process.env.API_KEY;
// log upload and download progress
const onDownloadProgress = console.log;
const onUploadProgress = console.log;

rembg({
    apiKey: API_KEY,
    inputImage: './input.png',
    onDownloadProgress,
    onUploadProgress,
    options: {
        returnBase64: true
        format: 'png' // or webp
    }
}).then(({ base64Image }) => {
    console.log(`✅🎉 background removed ${base64Image}`);
});

Input Image as Base64 or Buffer

Since version 1.1.8, the rembg function can accept an input image as a Buffer or Base64 object. Below is a quick demonstration:

import { rembg } from '../dist/index.js';
import dotenv from 'dotenv';
// Load environment variables from .env file
dotenv.config();

const base64Input = 'data:image/png;base64,/9j/4AAQSkZJRgABAQEASABIAAD/.....etc'
// API_KEY will be loaded from the .env file
const API_KEY = process.env.API_KEY;
// log upload and download progress
const onDownloadProgress = console.log;
const onUploadProgress = console.log;

rembg({
    apiKey: API_KEY,
    inputImage: {base64: base64Input}, // or simply an imageBuffer
    onDownloadProgress,
    onUploadProgress,
    options: {
        returnBase64: true
    }
}).then(({ base64Image }) => {
    console.log(`✅🎉 background removed ${base64Image}`);
});

Usage of returnMask flag

The library provides an option to return a mask of the image instead of the processed image. This is controlled by the returnMask parameter. When set to true, the function returns a mask. By default (if omitted), this parameter is set to false.

Code Snippet

rembg({
    apiKey: API_KEY,
    inputImage: './input.jpg',
    onDownloadProgress,
    onUploadProgress,
    options: {
        returnMask: true, // <----- Set to true to get the mask of the image
        returnBase64: true // Set to true to receive the result as a Base64 string
    }

}).then(({ base64Image }) => {
    console.log(`✅🎉 Mask retrieved: ${base64Image}`);
});

Below is the generated mask image using the rembg function with the mask option enabled:

This image demonstrates the result of the mask generation process. The mask typically highlights the main subject of the image with the background removed or made transparent.

This is very useful to work with Stable Diffusion for perfect area of inpainting, for example.

Remove Background and Resize

Code Snippet

rembg({
    apiKey: API_KEY,
    inputImage: './input.jpg',
    onDownloadProgress,
    onUploadProgress,
    options: {
        w: 1000,
        h: 760 // When both `w` and `h` are provided, RemBG will find the best dimensions that fit within the requested width and height while preserving the aspect ratio.
            // If you want to guarantee the exact size, set `exact_resize: true`.
        // exact_resize: true !!! be careful it can cause distortion !!!
    }

}).then(({ base64Image }) => {
    console.log(`✅🎉 Mask retrieved: ${base64Image}`);
});

Image Processing with New Parameters

The library now supports advanced image processing options including rotation, padding, and background color customization:

Code Snippet

rembg({
    apiKey: API_KEY,
    inputImage: './input.jpg',
    onDownloadProgress,
    onUploadProgress,
    options: {
        w: 800,
        h: 600,
        format: "WEBP",
        angle: 90,                    // Rotate image 90 degrees
        expand: true,                 // Add padding so rotated images aren't cropped
        bg_color: "blue"              // Set background color (hex: "#FF5733" or named: "blue")
    }
}).then(({ outputImagePath, cleanup }) => {
    console.log(`✅🎉 Background removed with rotation and custom background: ${outputImagePath}`);
    cleanup();
});