3.1.0 • Public • Published

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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 the latest WebP binaries:

curl -s | sudo bash

MacOS users may install WebP using homebrew:

brew install webp

or MacPorts:

sudo port selfupdate
sudo port install webp

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

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 consuming the input 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 promises.

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

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');

Providing custom spawn options

encoder.spawnOptions({detached: true});

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