diff --git a/index.js b/index.js
index bfd5a7c..f24e64f 100644
--- a/index.js
+++ b/index.js
@@ -37,8 +37,8 @@ alfy.alfred = {
 
 alfy.input = process.argv[2];
 
-alfy.output = (items, {rerunInterval} = {}) => {
-	console.log(JSON.stringify({items, rerun: rerunInterval}, null, '\t'));
+alfy.output = (items, {rerunInterval, variables} = {}) => {
+	console.log(JSON.stringify({items, rerun: rerunInterval, variables}, null, '\t'));
 };
 
 alfy.matches = (input, list, item) => {
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diff --git a/readme.md b/readme.md
index cd3d70f..0dced6c 100644
--- a/readme.md
+++ b/readme.md
@@ -234,6 +234,76 @@ alfy.output(
 
 <img src="media/screenshot-output.png" width="694">
 
+###### variables
+
+Type: `object`
+
+###### 1. Root level variable
+
+variables can be useful when passing variables in `script filter` to Alfred. 
+
+In alfred, variable includes `item-level variable` and `root-level variable`.
+
+You can set a `root-level variable` by putting variables in this options object in the following ways:
+
+Here's a `script filter` example using `root-level variable`.
+
+```js
+const alfy = require('alfy')
+const [userID, serviceProvider] = alfy.input.split('@', 2)
+const isValidEmail =  /* some boolean value indicating input is valid. */
+
+alfy.output(
+  [
+    {
+      title: `${alfy.input} is ${isValidEmail ? 'valid' : 'invalid'} email`,
+      arg: `${isValidEmail}`
+    }
+  ],
+  {
+    variables: {
+      email: `${alfy.input}`,
+      userID,
+      serviceProvider
+    }
+  }
+)
+```
+
+We can fetch these variables from this script by using `{var:email}`, `{var:userID}` like below screenshot.
+
+<img src="media/screenshot-var-desc-1.png" width="694">
+
+When we type abc@gmail.com, it gives us below notification.
+
+<img src="media/screenshot-var-desc-2.png" width="694">
+
+And this is the result of entering only abc (not valid email).
+
+<img src="media/screenshot-var-desc-3.png" width="694">
+
+###### 2. Item level variable
+
+If the value of variables must be different depending on the item, you must use item-level variables like this way.
+
+```js
+const items = [];
+items.push({
+	title: `${someInfo}`,
+	variables: {
+		title: `${someInfo}`
+	}
+});
+....
+
+alfy.output(items);
+```
+
+Passed variables can be used like `{var:apiKey}` in both ways.
+
+You can also use `{allVars}` to communicate all variables. [More info.](https://www.alfredapp.com/help/workflows/inputs/script-filter/json/)
+
+
 #### log(value)
 
 Log `value` to the [Alfred workflow debugger](https://www.alfredapp.com/help/workflows/advanced/debugger/).