# Passing the Patchworks signature as a header for callback requests

## Introduction

When a [callback](https://doc.wearepatchworks.com/product-documentation/process-flows/building-process-flows/process-flow-shapes/standard-shapes/trigger-shape/trigger-shape-callback) is generated via the [trigger shape](https://doc.wearepatchworks.com/product-documentation/process-flows/building-process-flows/process-flow-shapes/standard-shapes/trigger-shape), it includes a Patchworks signature - by default, this is defined as a URL parameter. However, some third-party systems do not accept URL parameters. 

In this case, the signature element should be removed from generated URLs and passed as a `patchworks-signature` request header instead.  

## The steps

{% stepper %}
{% step %}
**Generate a callback trigger**

Access the trigger shape and add a callback (or use an existing callback).
{% endstep %}

{% step %}
**Copy the callback URL**

Copy the callback URL, then paste it into your preferred editor. It will look something like this:

{% code overflow="wrap" %}

```
https://callbacks.wearepatchworks.com/api/v1/docsdemo/01jvgtcr9gr66t84wh2fg9kse37?patchworks_signature=fr80fg6e2g94jj908f1698htggrswgw6319ns6r194fh2nkekcht
```

{% endcode %}
{% endstep %}

{% step %}
**Save the Patchworks signature value from the callback URL**

Copy the signature value and paste it somewhere accessible - you'll need this value shortly. For example:

{% code overflow="wrap" %}

```
fr80fg6e2g94jj908f1698htggrswgw6319ns6r194fh2nkekcht
```

{% endcode %}
{% endstep %}

{% step %}
**Edit the callback URL**

Remove the entire URL parameter section of the URL (i.e. remove the `?patchworks_signature` element). The updated URL will look something like this:

{% code overflow="wrap" %}

```
https://callbacks.wearepatchworks.com/api/v1/docsdemo/01jvgtcr9gr66t84wh2fg9kse37
```

{% endcode %}
{% endstep %}

{% step %}
**Apply the updated URL in your callback requests & add a signature header**

Use the updated URL in your callback request AND add a `patchworks-signature` header. The value for this header will be the signature that you saved in step 3. For example:

<div align="left"><figure><img src="https://2440044887-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FLYNcUBVQwSkOMG6KjZfz%2Fuploads%2FtoePRek9Q5j1jgnLfTYQ%2Fcallback%20trigger%202a.png?alt=media&#x26;token=8457d9de-12d7-4307-a707-36d3d1ac169c" alt=""><figcaption></figcaption></figure></div>

{% hint style="info" %}
The header must be `patchworks-signature` NOT `patchworks_signature` .
{% endhint %}
{% endstep %}
{% endstepper %}