FinTech Trading Platform Development | Real-Time PWA, WebSockets, Admin CRM & Payment System

This is an existing, already-developed platform and codebase — not a new project built from scratch. We are looking for a senior team to take over the current system, review the existing frontend/backend architecture and code, understand the current trading logic, identify incorrect or weak implementations, fix reliability issues, and continue development from the existing codebase. The team must be comfortable taking ownership of a complex live project written by previous developers rather than starting over. We are looking for a genuinely senior Full-Stack FinTech development team to work on an advanced real-time trading platform. This is not a basic website, template project, or simple dashboard. The platform includes a real-time PWA trading interface, internal trading/market logic, WebSockets, live price and order updates, Redis/backend event handling, admin CRM and control systems, trader accounts, payment and withdrawal flows, risk controls, reporting, and multiple real-time trading tools. We need developers who understand how to build real production systems where every admin setting, trading control, calculation, and backend function has real logic behind it. A major requirement is that there must be: * No fake admin settings that only change the UI but do not affect the backend behavior. * No placeholder or simulated functionality presented as completed development. * No random/scripted market behavior where real order-driven logic is required. * No hardcoded values used instead of proper production logic. * No unfinished frontend controls without backend implementation. * No unreliable WebSocket synchronization between desktop, mobile/PWA, backend, Redis, and database. * No silent shortcuts that make a feature appear to work during a demo but fail under real usage. We want a senior developer or team that can review complex existing architecture, understand the business logic, identify weak or incorrectly implemented systems, and rebuild or improve them properly where necessary. Important experience includes: Real-time Node.js/backend architecture, React/PWA development, WebSockets, Redis Pub/Sub or similar event systems, PostgreSQL/MySQL, scalable trading or financial systems, ledger/balance logic, transaction integrity, payment APIs, withdrawal systems, admin CRM development, risk controls, audit logs, role/permission systems, security, performance optimization, concurrency handling, and production deployment. Experience with exchanges, trading platforms, financial systems, betting/exchange engines, gaming economies, wallets, payment platforms, or other high-concurrency real-time systems is highly valuable. The trading platform contains its own internal market ecosystem, so developers must be comfortable working with custom trading logic instead of simply connecting a frontend to an external market-price API. We expect the team to understand the full flow: Trader action → API/backend validation → trading engine → market calculation → Redis/event distribution → database/ledger → WebSocket update → trader interface/admin systems. Changes made from the admin side must produce measurable and technically explainable changes in the real system. If there is a market sensitivity control, liquidity control, behavioral parameter, risk setting, payout rule, or similar configuration, it must actually control the underlying engine — not just change a number on an admin screen. Code quality is extremely important. We need maintainable, structured, documented production code with proper separation of concerns, validation, error handling, logging, monitoring, testing, auditability, and version control. We are specifically looking for senior developers who can independently understand complex requirements and challenge incorrect technical decisions when necessary. We do not want a team that simply marks tasks as completed without deeply testing whether the feature works correctly in real conditions. When applying, please explain: 1. Your experience building real-time FinTech/trading/exchange systems. 2. Your strongest backend technologies. 3. Your experience with WebSockets and Redis. 4. Whether you have built financial ledgers, wallets, withdrawals, payment systems, or trading engines. 5. How you test that an admin configuration actually affects the production engine correctly. 6. How you handle concurrency when many users trade simultaneously. 7. Examples of technically complex systems your team has built. 8. Who will actually work on the project and the seniority of the developers involved. We prefer a serious long-term technical partner rather than a team focused only on quickly completing tickets. Please apply only if you are comfortable taking responsibility for production-level financial and real-time system architecture and can demonstrate senior-level engineering experience.