Using Variables in API Requests

Once you’ve defined variables in Requestly, whether global, environment, collection, or subcollection, you can reference them directly in your API requests. This allows you to dynamically inject values into URLs, headers, request bodies, scripts, and more.

Use Variables in API Requests

Step 1: Create or Open a Request

Create or open an existing request in the API Client.

Step 2: Replace Static Values

Replace static values with your environment variables using the {{variable_name}} syntax.

Step 3: View Variable Values

Hover over a variable to see its resolved value.

Test Your Setup

Step 1: Execute the Request

Click Send to execute the request.

Step 2: Verify Resolved Values

Check the resolved values in the Request Preview to ensure that variables are substituted correctly.

If a variable isn’t resolving, verify that the variable name matches exactly (case-sensitive) and is present in the selected environment.

Array variables

When a variable holds an array value, referencing it inline with {{variable_name}} renders the JSON text of the list. For example, an array variable holding a and b resolves to ["a","b"] in a URL, header, or body.

To work with individual items, read the variable in a script, where it is returned as a real array. See rq.environment for reading array variables in scripts.

Composite variables

Composite variables allow you to reference one variable inside another variable’s value. This is useful when you want to build dynamic values from other variables.

How it works

Define a variable that references another variable using the {{variable_name}} syntax:

Variable Name	Value
base_url	api.example.com
api_endpoint	https://{{base_url}}/v1

When api_endpoint is resolved, it becomes https://api.example.com/v1.

Example: Building dynamic URLs

You can chain multiple variables together:

Variable Name	Value
env	staging
region	us-east
base_url	{{env}}.{{region}}.api.example.com
full_url	https://{{base_url}}/users

The full_url resolves to https://staging.us-east.api.example.com/users.

Circular dependency handling

If you create circular references (e.g., var_a = {{var_b}} and var_b = {{var_a}}), Requestly detects this and leaves the variables unresolved to prevent infinite loops.

Autocompletion and syntax highlighting for variable references inside the variables table is not currently supported.