> For the complete documentation index, see [llms.txt](https://docs.langstack.com/welcome/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.langstack.com/welcome/get-started/learn-langstack/introduction-to-rest-api/path-parameter.md).

# Path parameter

* Path parameters are variables that appear within the URL that points toward a specific resource. 
* There can be multiple path parameters. 
* The Path parameter can be a constant text or a variable value added after the API group base URL. 

## Constant Path Parameter

In a constant path parameter, on calling the API, the representation text of the path parameter in the URL is consistent. It does not change on calling the API.

{% embed url="<https://media.langstack.com/documentation/media/images/code/training_manual/chapter_4/ch4urlconstpathparam.png>" %}

### How to create a constant path parameter

To define a constant path parameter, in the Details tab>API name or path parameters field:&#x20;

* Enter the parameter name
* Press Enter. It displays in a blue bubble.&#x20;

In the URL, the constant path parameter displays without curly brackets.

{% embed url="<https://media.langstack.com/documentation/media/images/code/training_manual/chapter_4/ch41constparam.png>" %}

## Variable Path parameter

In a reference or variable path parameter, on calling the API, the representation text of the path parameter in the URL can vary depending on the data to query the API with. \
For example, the URL below has a variable path parameter “name,” where the API caller can put the customer's name in that variable path parameter and find out the rating of the customer.

{% embed url="<https://media.langstack.com/documentation/media/images/code/training_manual/chapter_4/ch4urlvarpathparam.png>" %}

### How to create a variable path parameter

To define a variable path parameter, in the Details tab>API name or path parameters field,&#x20;

* Click the \[+] button.

![](/files/xuPYlxNdEV631Nhh9h7k)

* To define the variable parameter:
  1. Enter the parameter name.
  2. Click the \[Save] button.

{% embed url="<https://media.langstack.com/documentation/media/images/code/training_manual/chapter_4/ch4params2advarparam2.png>" %}

* The variable path parameter is displayed in a white bubble ( the “expression bubble”). In the URL, it is displayed with curly brackets.

{% embed url="<https://media.langstack.com/documentation/media/images/code/training_manual/chapter_4/ch4params3advarparam3.png>" %}

* After saving the parameter name, go to the Inputs & outputs tab>Path Parameters section. \
  The created variable parameter is displayed with data type as “string”.&#x20;

![](/files/VkHQuouZHcOD510q2dmF)

* Users must add the sample for the parameter. (as not adding the path parameter will prevent the user from saving the API successfully)

![](/files/q6dopoWbap3MzkTujydJ)