The next step towards integration is in Magento 2.x admin.

1. Log in to your Magento
2. Click Integrations and then Add New Integration
3. In the Integration Info tab, fill in the following fields

3.1.Name = Price2Spy
3.2.Email = it can be left blank
3.3.Callback URL = https://spy.price2spy.com/ei/magento2/callback/
3.4.Identity Link URL = https://spy.price2spy.com/ei/magento2/authorize
3.5.Current User Identity Verification = current password for Magento

4. The following data needs to be highlighted in the API tab 

• Catalog
  • Inventory
    • Products
    • Categories
• Stores
  • Attributes
    • Products

5. Click Save and Activate

6. Click Allow

Note: You need to be logged out of your Price2Spy account in the same browser where the integration is performed

7. (Optional) If Popup Blocker is on, just turn it off

8. A new window will open, where you enter your Price2Spy credentials (username/password).

After this, your Magento 2 will be linked to your Price2Spy account and further steps are in the Price2Spay account.

So you see automatic Step 3.

In this step, you need to select the categories you want. If nothing is selected then Price2Spy thinks you want all categories.

Once you have selected some or all of the categories, clicking Next takes you to Step 4.

After that, a window like this will appear, showing that everything is connected and that the first execution needs to pass.

When the first execution is over in a few minutes, refresh the browser, and data from your Magento will appear at the bottom of the page.

Troubleshooting

1. If an error occurs when clicking Allow. First, check if you are logged out of your Price2Spy account. If so and then an error occurs. You need to delete the made connection, then make a new connection. Following all steps only the Callback URL and Identity Link URL fields remain blank. After that, when you click on Allow again, a window with 4 tokens will open. Those tokens as well as the store URL need to be sent to the manager. You can see additional documentation for this issue https://devdocs.magento.com/guides/v2.4/get-started/authentication/gs-authentication-token.html#integration-tokens
2. When a new window opens, after clicking on Allow in Magento admin, and you log in there, there is a possibility that then the connection to your Magento 2.x will not work. If it happens that it is not connected, then it is necessary to do one of the two actions

First action: Close this new window and open a new one and log in to your Price2Spy account. After that, you need to click on Misc/Link My Store and then Magento and Price2Spy will connect as in the picture.

Second action: Delete the cache data in the browser and then do the first action.