Secure transaction platform with escrow account

Need to develop a full-featured web application for a secure transaction service (escrow) that acts as an intermediary between buyer and seller in online transactions. The logic is transparent: the buyer deposits funds into an escrow account, funds are frozen on the platform, and the seller receives payment only after the agreed outcome is confirmed. The system must support multi-stage deals: a large order is divided into milestones, and each milestone unlocks its portion of held balance after the buyer accepts completed work. Any change to deal status—created, paid, in progress, delivered, paid out, returned, disputed—is recorded in an immutable transaction log with timestamps and participant IDs so parties and moderator can reconstruct the entire history. A dispute resolution process is mandatory: if disagreement arises, the deal locks, both sides upload evidence and a moderator issues a binding decision that divides or returns held funds. Identity verification (KYC) with document upload and status control should unlock access to large transactions and fund withdrawals. Integration with at least one payment provider for card top-up and one payout channel is expected, plus webhook processing for asynchronous confirmations. Clean REST endpoints, role-based cabinets for buyer, seller and moderator, email and in-app notifications for each log event and detailed documentation are needed. Security is a priority: signed callbacks, idempotent balance operations and protection against double payout of frozen funds.