We need a complex trading bot. We need basic trading options: Placing Buy/Sell Orders (Instant & Conditional). Cancelling orders, showing current coin price. For the beginning we only need an integration of bittrex api. The user can purchase subscriptions which are paid by btc. We also need a simple referral system, so every user has a referral link which he can share to other users for registration. Every purchase of this user will bring certain amount of the buy sum back to the referral. It would be nice to have 3 languages. (translations will be provided by us). Then we need an admin backend to manage subscription price, some statistics and managing deposits and withdrawals (e.g referral commissions).
Flow Chart can be provided.