diff --git a/readme.md b/readme.md
index 2ec9b42..93b2152 100644
--- a/readme.md
+++ b/readme.md
@@ -51,7 +51,60 @@ This will:
 
 You should be able to launch the app on the platform you built for. If not, check your settings and try again.
 
-**Be careful** not to include node_modules you don't want into your final app. For example, do not include the `node_modules/electron-packager` folder or `node_modules/electron-prebuilt`. You can use `--ignore=node_modules/electron-prebuilt` to ignore of these
+**Be careful** not to include node_modules you don't want into your final app. `Electron-packager`, `electron-prebuilt` and `.git` will be ignored by default. You can use `--ignore` to ignore files and folders, e.g. `--ignore=node_modules/electron-packager`.
+
+### API
+```javascript
+var packager = require('electron-packager')
+packager(opts, function done (err, appPath) {
+
+})
+```
+#### packager(opts, callback)
+
+##### opts
+**Required**  
+`dir` - *String*  
+The source directory.
+
+`name` - *String*  
+The application name.
+
+`platform` - *String*  
+Allowed values: *linux, win32, darwin*
+
+`arch` - *String*  
+Allowed values: *ia32, x64*
+
+`version` - *String*  
+Semver, see https://github.com/atom/electron/releases
+
+**Optional**  
+`out` - *String*
+
+`icon` - *String*
+
+`app-bundle-id` - *String*
+
+`app-versionv` - *String*
+
+`helper-bundle-id` - *String*
+
+`ignore` - *String*
+
+`prune` - *Boolean*
+
+`asar` - *Boolean*
+
+`sign` - *String*
+
+##### callback
+
+`err` - *Error*  
+Contains errors if any.
+
+`appPath` - *String*  
+Path to the newly created application.
 
 ### Building windows apps from non-windows platforms