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NPM Package Linux Build Status Windows Build Status Dependency Status


Node.js wrapper for cwebp and dwebp binaries from WebP image processing utility.


npm install cwebp

Getting latest version of WebP

You can get latest WebP source, pre-compiled binaries and installation instructions from its official website, or from its downloads repository.

Linux users may use this installation script to automatically download and install latest WebP binaries:

curl -s | sudo bash

MacOS users may install WebP using MacPorts:

sudo port selfupdate
sudo port install webp

If none of it suit your needs, you may build the WebP utilities yourself.

Alternative ways to install WebP

MacOS users may install webp 0.5.0 using homebrew:

brew install webp

You may also install webp 0.3.x as npm module:

npm install webp

WebP versions compatibility

node-webp version Fully compatible WebP versions Partially compatible WebP versions
0.1.x all versions all versions
1.x 0.4.1 and later all versions
2.x 0.5.0 and later all versions


var CWebp = require('cwebp').CWebp;
var DWebp = require('cwebp').DWebp;

var encoder = new CWebp(source_image);
var decoder = new DWebp(source_webp);


// new is optional
var encoder = CWebp(source_image);
var decoder = DWebp(source_webp);


// Backward-compatibility with cwebp@0.1.x
var CWebp = require('cwebp');

Specifying path to cwebp binary

By default node-webp looks for cwebp and dwebp binary in your $PATH.

Specifying path as a constructor option

var Webp = require('cwebp');
var binPath = require('webp').cwebp;

var webp = new Webp(source, binPath);

Changing default behaviour

var CWebp = require('cwebp').CWebp;
CWebp.bin = require('webp').cwebp;

var encoder = new CWebp(source);
var DWebp = require('cwebp').DWebp;
DWebp.bin = require('webp').dwebp;

var decoder = new DWebp(source);

N.B.: webp npm module provide old webp 0.3.x binaries.

Available source types

When source is a string node-webp treats it as a file path.

var CWebp = require('cwebp').CWebp;
var DWebp = require('cwebp').DWebp;

var encoder = new CWebp('original.jpeg');
var decoder = new DWebp('converted.webp');

It also accepts Buffers and Streams.

var encoder = new CWebp(buffer);
var decoder = new DWebp(stream);

Note that node-webp will start listening to the data in a source stream only when .write(), .stream() or .toBuffer() is called.

Encoding and decodind WebP images

encoder.write('image.webp', function(err) {
    console.log(err || 'encoded successfully');
decoder.write('image.png', function(err) {
    console.log(err || 'decoded successfully');

Getting output image as a Buffer

decoder.toBuffer(function(err, buffer) {
    // ...

Getting output image as a readable Stream

var stream =;

stream.on('error', function(err) {
  // something bad happened

Using promises

node-webp supports A+ promises.

encoder.write('image.webp').then(function() {
    // ...
encoder.toBuffer().then(function(buffer) {
    // ...
}); {
    // ...

node-webp uses when.js library.

Specifying conversion options

node-webp provides helper functions for most of cwebp and dwebp conversion options. For the full list of available helpers see methods.json file.


Sending raw command

encoder.command('-d', 'dump.pgm');



node.js wrapper for cwebp and dwebp binaries from WebP image processing utility




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