---
title: Browser Builds
description: Guide to using and writing modules and optimizing browser bundles.
---
# Browser Builds
Bitcore and most official submodules work in the browser, thanks to [browserify](http://browserify.org/) (some modules are not fully compatible with web browsers).
The easiest and recommended way to use them, is via [Bower](http://bower.io/), a browser package manager, and get the release bundles.
For example, when building an app that uses `bitcore` and `bitcore-ecies`, you do:
```sh
bower install bitcore
bower install bitcore-ecies
```
You can also use a `bower.json` file to store the dependencies of your project:
```json
{
"name": "Your app name",
"version": "0.0.1",
"license": "MIT",
"dependencies": {
"bitcore-ecies": "^0.10.0",
"bitcore": "^0.10.4"
}
}
```
and run `bower install` to install the dependencies.
After this, you can include the bundled release versions in your HTML file:
```html
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<script src="bower_components/bitcore/bitcore.min.js"></script>
<script src="bower_components/bitcore-ecies/bitcore-ecies.min.js"></script>
</head>
<body>
<script type="text/javascript">
var bitcore = require('bitcore');
var ECIES = require('bitcore-ecies');
// etc...
</script>
</body>
</html>
```
## Building Custom Bundles
If you want to use a specific version of a module, instead of a release version (not recommended), you must run browserify yourself.
You can get a minified browser bundle by running the following on the project root folder.
```sh
browserify --require ./index.js:bitcore | uglifyjs > bitcore.min.js
```
(for bitcore)
```sh
browserify --require ./index.js:bitcore-ecies --external bitcore | uglifyjs > bitcore-ecies.min.js
```
(for a bitcore module, `bitcore-ecies` in the example)
## Development of Modules
*Note:* You probably don't want to use this method, but `bitcore-build`, as explained above. This is left here as documentation on what happens under the hood with `bitcore-build`.
When developing a module that will depend on Bitcore, it's recommended to exclude Bitcore in the distributed browser bundle when using browserify and to use the `--external bitcore` parameter. It will produce a smaller browser bundle, as it will only include the JavaScript that is nessessary, and will depend on the Bitcore browser build which is better for distribution.
### Building the Bundle Manually
**Step 1**: Require Bitcore
Here we require Bitcore and define the namespace (`index.js`):
```javascript
var bitcore = require('bitcore');
var PrivateKey = bitcore.PrivateKey;
var PublicKey = bitcore.PublicKey;
var Address = bitcore.Address;
```
See the [main file](https://github.com/bitpay/bitcore/blob/master/index.js) for bitcore for a complete list, as well as the [Bitcore Documentation](index.md).
**Step 2**: Browserifying
Next we will generate a browser bundle using [browserify](https://www.npmjs.com/package/browserify) by running the command:
```bash
browserify index.js:module-name --external bitcore -o module-name.js
```
This will output a file `module-name.js` with only the code loaded from `index.js` (bitcore.js will need to be loaded beforehand, which is around 145KB gzipped)
**Step 3**: Uglifying
This can be further optimized by using [uglifyjs](https://www.npmjs.com/package/uglify-js), and running the command:
```bash
uglifyjs module-name.js --compress --mangle -o module-name.min.js
```