How to efficiently fight against fraud?

As a platform, you are in charge of a permanent first level customer due diligence, using the support of your commercial and technical team. To maximise your platform security, we recommend that you:

supervise the behaviour of your clients on your platform
detect unusual behaviour or transactions and notify our teams at fraud@mangopay.com and wait for our Fraud Analyst feedback
analyse the refusal codes: a short message is associated with refusal codes to provide more details of the reason for the refusal
create alerts and/or trigger the 3DS according to your activity and users' regular behaviours, for example: if a first-time user is paying more than the average payment basket
per default, only allow pay-outs after 48 hours.
from 8PM to 8AM and weekends, try not to process or validate any pay-outs for clients who are not KYC approved and who request an amount exceeding a limit defined by you

Flag some types of behaviour, for instance:

flag pay-outs requested right after the transaction was completed
flag wallets that receive many refusal codes such as fraud codes, or 3DS failed codes
flag payments that are above your average payment basket
flag payments occurring too regularly by one same user over a day, a week or a month
flag a user who wants to register a new bank account: maybe set up a code confirmation system that asks for a cash-out of more than a certain amount (to be defined by you)