Lead Fintech & Web3 Payments Engineer (Gateway, POS, UPI & Crypto Rails)

Job Title: Principal Payments Architect & Lead Integration Engineer (Fiat, Web3, & Global Rails) Location: [Remote / Hybrid / India] Job Type: [Full-Time / Contract] Experience Level: Lead / Principal (7+ years) 🚀 About the Role We are building a highly disruptive, omni-channel transaction ecosystem that unifies traditional fiat infrastructure, instant retail networks, and decentralized digital asset liquidity. We are seeking a powerhouse Principal Payments Engineer to architect our multi-rail transactional backbone. In this role, you will design the core routing matrices that seamlessly connect global card networks, cross-border banking systems (SWIFT), physical/cloud POS systems, instant domestic networks (UPI), and institutional Web3 On/Off-Ramp layers. If you can confidently map out a transaction path that touches a retail terminal, an NPCI switch, a Visa network, and an institutional crypto liquidity desk in under two seconds, this role is built for you. 🎯 Key Responsibilities Multi-Rail Core Architecture: Design and scale a unified, highly idempotent transaction processing engine that handles complex routing across Cards, SWIFT, UPI, and Crypto rails. Web3 On/Off-Ramp Engineering: Build deep, high-throughput integrations with institutional crypto platforms like BVNK and Binance (Binance Pay / Exchange Core APIs) for real-time asset conversion, automated order book execution, and stablecoin settlements ($USDT$, $USDC$). Global Fiat & Network Connectivity: Architect and manage direct processing-level integrations with international card schemes and international banking networks using modern core financial messaging standards. Instant Payments & Hardware: Drive the development of UPI frameworks (dynamic QR codes, intent flows, collect requests) and physical/smart Android POS terminal applications (peripheral synchronization, offline capabilities). Automated Clearing & Reconciliation: Construct multi-currency, double-entry financial ledgers capable of real-time currency conversion, gas fee optimization, bank settlement clearing, and automated dispute/chargeback processing. Ironclad Security & Compliance: Enforce industry-standard compliance across both traditional and Web3 ecosystems (PCI-DSS Level 1, PA-DSS/PCI-SSF, Crypto Travel Rule/VASP, AML, and automated KYC pipelines). 🛠️ Technical Requirements & Deep-Dive Stack 1. Financial Messaging & Core Networks (Crucial) Card Networks (ISO 8583): In-depth knowledge of ISO 8583 messaging protocol variants for payment routing, clearing, authorization, and settlement frameworks. Deep understanding of 3D Secure (3DS), card tokenization, and HSM key management (DUKPT). SWIFT Network (ISO 15022 / ISO 20022): Expert-level experience with international banking messaging. Must have hands-on experience parsing, generating, and validating ISO 15022 (MT103, MT202) and migrating/architecting ISO 20022 (MX structures: pain, pacs, camt) for cross-border treasury movements. UPI Infrastructure: Direct engineering experience interfacing with NPCI frameworks, managing Virtual Payment Addresses (VPAs), transaction polling, and sub-second webhook callback matching. POS Hardware & Specs: Deep knowledge of EMVCo specifications, L1/L2/L3 certification pathways, and contactless (NFC) payment kernels built into smart Android/Linux terminals. 2. Crypto & Exchange Infrastructure Liquidity Integration: Proven experience integrating with Binance API/Webhooks (Spot/Margin trading desks, liquidity pools, order books) and institutional payment rails like BVNK for real-time B2B settlements. On/Off Ramp Orchestration: Strong understanding of blockchain custody solutions (e.g., Fireblocks, Copper) or smart contract interaction (Solidity/Rust) across EVM and non-EVM layers to handle digital asset settlement pipelines. Risk Management: Experience building systems to mitigate slippage, handle gas optimization, and hedge liquidity volatility risks during order matching. 3. Engineering & Distributed Systems Backend Frameworks: Master-level capabilities in a strongly typed, highly concurrent backend ecosystem: Go (Golang), Java, Rust, or C# .NET Core. Database & Ledger Management: Deep experience with PostgreSQL or MySQL tuned for extreme ACID compliance, transaction isolation, and immutable append-only ledgers. Message Streaming: Real-world reliance on message brokers such as Apache Kafka or RabbitMQ to securely orchestrate multi-step, asynchronous processing flows (e.g., initiating a SWIFT transfer or Crypto Off-Ramp instantly after a card authorization). 💼 Behavioral & Security Mindset Defensive Engineering: You treat every network call as potentially compromised. You inherently architect against race conditions, replay attacks, double-spending, and partial state drops. Root-Cause Investigator: The ability to calmly dive into distributed tracing logs and isolate why a cross-border settlement failed between an on-premise POS machine, an acquiring bank, and a crypto liquidity provider. Regulatory Adaptability: Comfortable collaborating with compliance teams to dynamically adapt core codebases as global fiat, banking, and crypto regulatory frameworks evolve.