You can export your list of leads to any custom system through Webhooks.
To integrate with Webhooks, follow these steps:
Click on the Leads category on the left side of your screen. There you can see emails entered via popups.
Click the Export to CRMs button.
Enter Post URL where you want parameters from popup request to be submitted. If the URL requires some authorization (e.g. token or api key), you can include the name of token (or api key parameter) and value.
Check the Live export after submit checkbox to save all your leads automatically.