Codementor triggers a modal to ask for referrals after each mentor session

Codementor knows that there are more opportunities of having you sharing a referral link either when you are happy with their service, either when you have just spent some of your credit. Or both. After each session you might have with one of their mentors, a modal is triggered after you terminate the session, inviting you to get $25 free if you bring new users. In a similar way, Digital Ocean are doing the same but within their monthly invoices.