Exporting Test Collections in Postman Jetpack

The answers above work well if you only want to export one collection.

If you have many collections and want to export them all, there's a better way:

Wrench icon (top-right) -> Settings -> Data tab -> Export Data -> Download

This will create a single json file with all your collections.

If you open Postman and look at the sidebar on the left, then hover over the name of the collection there five options: 'Add Folder', 'Edit Collection', 'Duplicate Collection', 'Share Collection', and 'Delete Collection'. Select the 'Share Collection' option and from there you will see a 'Download' button that will allow you to export your collection as the JSON file.

I took pictures to help people more.

Export one collection

The first way is by clicking on ... button and then clicking on export (or share if make sense)

The other way is to click on > button and then clicking on download collection

Both will give you your data in JSON format which you can use to import on another postman too.

Update (Export all collections as Cristi Diaconescu has mentioned)

and then Data tab> download

Postman let's you export collections in a JSON file. Click on the "Share" button in the sidebar and then click "Download" in the modal that opens up.

Best way which I used, Create a login on postman and whenever You do login on another computer login with the same account, You will get all the data.

Otherwise, Export the data into Json format from setting->data. And the same json can be used for import.