We are building an advanced USDT Buy/Sell platform with full automation, compliance, and wallet management. We are looking for an experienced Blockchain Developer to handle only blockchain-related development. Note: Backend, frontend, KYC, banking, admin panel, and UI work are handled by our internal team. Your responsibility is blockchain logic, wallets, transactions, and listeners only. Scope of Blockchain Work 1. USDT Wallet Infrastructure Create and manage USDT wallets (Hot & Cold) Support TRC20 / ERC20 (network to be finalized) Secure private key management Address generation for deposits 2. Buy USDT – Blockchain Flow Send USDT from Hot Wallet to user address Handle transaction creation, signing, and broadcasting Confirm transaction via blockchain confirmations Provide TX hash & status callback to backend 3. Sell USDT – Deposit Listener Generate unique deposit address / TAG / MEMO per user/order Implement blockchain listener to detect incoming USDT Validate confirmations Prevent duplicate or replay crediting 4. Hot–Cold Wallet Automation Monitor Hot Wallet balance Auto-sweep excess USDT to Cold Wallet Cold → Hot transfer logic with manual / multi-approval support Gas / fee optimization 5. Internal Wallet Logic (Ledger Support) Support wallet-to-wallet internal transfers (off-chain) Ensure AML-friendly transaction traceability Transaction metadata support (user ID, order ID) 6. Security & Compliance Support (Blockchain Side) Address blacklist checks High-risk wallet flagging support Transaction velocity monitoring hooks Logging for audits 7. Automation & Background Services Blockchain confirmation service Auto-retry failed broadcasts Daily reconciliation support with backend Fail-safe handling for partial confirmations Tech Stack (Preferred) Node.js / Python Web3.js / Ethers.js / TronWeb Secure key storage (HSM / Vault / Encrypted Storage) Experience with USDT smart contracts REST / Webhook-based integration What We Expect From You Strong experience in crypto wallets & USDT handling Prior work on exchange / P2P / crypto platforms Deep understanding of hot–cold wallet architecture Security-first approach Clean, documented, production-ready code Deliverables Blockchain wallet & transaction modules Deposit listener service Hot–cold wallet automation API/Webhook integration with backend Deployment & testing support Project Type Long-term project Contract / Freelance Budget: Discussed after technical discussion To Apply, Please Share Previous blockchain / USDT projects Networks worked on (ERC20 / TRC20 / BSC etc.) GitHub or code samples (if available) Availability & estimated timeline