For around 90% of our projects, clients only need to pay 50% as a deposit to start the projects. We will have official contracts with clients and after the payment, a invoice would be provided too. After we finish all of our work and clients approve the close of projects, they can pay for the rest before our moving projects onto their own severs or published in mobile marketplaces. For some smaller jobs like fixing hacking problems, upgrading websites, data entries and etc, we only accept full prepayments. But full refund is guaranteed if we could not finish the job right.