***

id: 205aae9e-d6d0-432b-a716-8fd22c8386c7
title: Execute SWML
description: >-
Call Flow Builder node to execute a remote SWML document and return to the
current document.
slug: /reference/execute-swml
max-toc-depth: 3
----------------

Execute a remote [SWML](/docs/swml) document and return to the current document.
Use `%{return_value.['object_field']}` to reference the return values from the external SWML.

## **Output Node Connectors**

<ParamField path="Condition" type="string" toc={true}>
  The condition that is evaluated to determine which path to take. Additional conditions can be added by clicking the `Add condition` button. Additional conditions will act as JavaScript `else-if` statements.
</ParamField>

<ParamField path="Else" type="string" toc={true}>
  The path to take if none of the conditions are met.
</ParamField>

## **Node Settings**

<ParamField path="URL" type="string" toc={true}>
  The URL of the SWML document to execute. The URL **must** return swml in valid `JSON` or `YAML` format.
</ParamField>

<ParamField path="Params" type="object" toc={true}>
  The parameters to pass to the SWML document.
</ParamField>

<ParamField path="Meta" type="object" toc={true}>
  The metadata to pass to the SWML document. A JSON object to serialize.
</ParamField>

<ParamField path="Conditions" type="string" toc={true}>
  The conditions that are evaluated to determine which path to take. Additional conditions can be added by clicking the `Add condition` button. Additional conditions will act as JavaScript `else-if` statements.
</ParamField>

## **Example**

In this example, we will execute a SWML script that is hosted on a remote server.
When making a request to the server, we will pass the `User` and `Token` parameters.

The SWML document will return a JSON object with a [play](/docs/swml/reference/play) method field.
This play field will be used for TTS (Text-to-Speech) in the current document
and will welcome the user with the `User` parameter and say the `Token` parameter.

<Frame caption="Call Flow using the Execute SWML node." ogImage>
  ![Execute SWML node example that executes a remote SWML document.](https://files.buildwithfern.com/signalwire.docs.buildwithfern.com/docs/a9a8a7ceba0c91f1dd204c421d59c6c1e6fb603697694b704b6dd28dda61daa4/assets/images/call-flow/nodes/swml_node.webp)
</Frame>

### Execute SWML Node Settings

* **URL**: Self-hosted [ngrok](https://ngrok.com/) URL.
* **Params**: `{ "Content-Type": "application/json", "User": "user_1", "Token": "123" }`
* **Meta**: None
* **Condition**: `%{return_value.return_value} === 1`

***

### SWML Document

Below is the SWML document that will be executed.

```yaml andJSON
sections:
  main:
    - play: 'say: Hello <USER_NAME>, welcome to the SWML demo! Your token is <TOKEN>!'
```

***

### Server Code

Below is the server code that will return the SWML document.

<Tabs>
  <Tab title="Node.js">
    #### Pre-requisites

    * [ExpressJs](https://expressjs.com/) installed in your environment.
    * [ngrok](https://www.npmjs.com/package/ngrok) installed in your environment.

    ```js
    const express = require('express');
    const ngrok = require('ngrok');
    const app = express();

    // Body parser middleware to handle JSON payloads
    app.use(express.json());

    // Define the route
    app.post('/swml', (req, res) => {

        let reqBody = req.body;
        console.log(reqBody);

        let user = reqBody.params.User;
        let token = reqBody.params.Token;


        const swml = {
            "sections": {
                "main": [
                    {
                        "play": `say: Hello ${user}, welcome to the SWML demo! Your token is ${token}!`
                    }
                ]
            }
        };

        res.json(swml);
    });


    // Start the server and use ngrok to expose it
    const port = 5000;
    app.listen(port, async () => {
        const url = await ngrok.connect(port);
        console.log(`Server running on ${url}`);
    });
    ```
  </Tab>

  <Tab title="Python">
    #### Pre-requisites

    * [Flask](https://flask.palletsprojects.com/en/3.0.x/installation/#install-flask) installed in your environment.
    * [Pyngrok](https://pypi.org/project/pyngrok/) installed in your environment.

    ```python
    from flask import Flask, request
    from pyngrok import ngrok

    app = Flask(__name__)

    @app.route('/swml', methods=['POST'])
    def swml_route():
        # Extracting data from request JSON
        req_data = request.json
        print(req_data)
        user = req_data['params']['User']
        token = req_data['params']['Token']

        swml = {
            "sections": {
                "main": [
                    {
                        "play": f"say: Hello {user}, welcome to the SWML demo! Your token is {token}!"
                    }
                ]
            }
        }

        return swml

    if __name__ == "__main__":
        port = 5000
        public_url = ngrok.connect(port).public_url
        print(f" * Running on {public_url}")
        app.run(port=port)
    ```
  </Tab>
</Tabs>