Write a pre-request script to add an environment variable in Insomnia

Uses: Insomnia

Prerequisites

Insomnia

Download and install Insomnia.

Create and configure a collection

For this tutorial, you’ll need a collection in Insomnia. A collection is essential for this tutorial to function, but creating one isn’t the focus of this guide. Use the following to add a pre-configured collection to Insomnia:

This pre-configured collection contains:

The example “Flights Service 0.1.0” spec added as a document
A collection generated from the spec
Pre-configured base environment variables

Add a pre-request script

In this example, we’ll configure a pre-request script that sets a variable in the request:

In Insomnia, navigate to the “Flight Service 0.1.0” document.
Click the Collection tab in the sidebar.
In the sidebar of your collection, select the Get a specific flight by flight number request.
Click the Scripts tab on the request.
Insomnia provides example pre-request scripts. From the Pre-request tab, click Variable Snippets at the bottom of the pane and select Set an environment variable.
In the example script, replace variable_name with flightNumber and variable_value with KA0285. The script should look like the following:
```
insomnia.environment.set("flightNumber", "KA0285");
```
Copied!

Validate the pre-request script

Now that we created a pre-request script, we can validate it by sending a GET request to the /flights/{flightNumber} endpoint.

Click Send. You should get a 200 status code and the following response:

{
	"number": "KA0285",
	"route_id": "LHR-SFO",
	"scheduled_arrival": "2024-04-03T11:10:00Z",
	"scheduled_departure": "2024-04-03T22:15:00Z"
}

Copied!

FAQs

Can I migrate my pre-request scripts from another API client, like Postman, to Insomnia?

Yes, you can copy and paste your pre-request scripts directly from Postman into an Insomnia pre-request script.

Can I run pre-request scripts without a collection?

No, you can only run pre-request scripts from a collection or a collection that was generated from a document.

Can I use variables in request paths?

Yes. Insomnia supports variables in request paths through template tags and environment variables.

Define variables in your environment, then reference them directly in a request URL using Liquid syntax, for example:

https://api.example.com/users/{{ user_id }}