Senior Blockchain Developer – Payment Gateway Platform

As a Senior Blockchain Developer at Dezzex, you will design, build, and scale an enterprise-grade crypto payment gateway platform. You'll architect systems that allow businesses and merchants to accept, receive, and manage multi-currency crypto payments (primarily stablecoins like USDC and USDT) alongside traditional fiat bank account payouts. You'll lead the integration of Fireblocks API for institutional-grade wallet custody, connect automated bank settlement rails, and build reliable multi-chain payment flows.

What you'll do

• Design and develop scalable backend microservices for crypto payment processing, merchant checkout widgets, invoice generation, and transaction reconciliation.
• Implement Fireblocks REST APIs, Webhooks, and SDKs for multi-asset vault management, wallet generation, transaction signing, sweep/treasury operations, and policy engine enforcement.
• Build native support for USDC and USDT payments across multiple networks (Ethereum, Solana, Polygon, Arbitrum, Base, Tron), managing HD wallet generation, deposit address routing, and gas optimization/fee delegation.
• Connect with banking APIs, instant payment networks (such as UAE Aani, India UPI, or global SWIFT/ACH), and liquidity providers for automated crypto-to-fiat conversion and merchant payouts.
• Implement real-time FX-rate lookup and dynamic pricing engines to accept payments in various cryptocurrencies while settling to merchants in their preferred local fiat or stablecoin currency.
• Build real-time blockchain event indexers, transaction monitoring systems, and webhook engines capable of handling re-orgs, gas spikes, and partial payment edge cases.
• Enforce robust security practices around key management, transaction signing, AML/KYT screening (Chainalysis, Elliptic), and Travel Rule compliance for cross-border flows.

What you bring

• 3-6+ years of professional software development experience, with 2+ years dedicated to production-grade Web3 and blockchain solutions.
• Hands-on experience integrating Fireblocks API and SDK, including Vault creation, Transaction creation, Webhooks, and Asset management.
• Deep understanding of Payment Gateway Architecture: payment intents, webhook handling, reconciliation engines, double-entry ledgers, and transaction finality tracking.
• Proven experience building native USDC and USDT transaction flows using ERC-20, SPL, and TRC-20 token standards.
• Proficiency in Node.js/TypeScript, Go (Golang), or Python for high-throughput backend services.
• Experience integrating with Banking APIs and Payment Processors, including Open Banking, SWIFT, ACH, and local real-time rails.
• Solid understanding of EVM smart contracts (Solidity/Vyper) and interacting with blockchain RPC nodes via Web3.js, Ethers.js, or Viem.

Nice to have

• Prior experience at a Crypto Payment Service Provider, FinTech, or Web3 payment gateway.
• Experience with cross-chain swaps, DEX aggregators, or liquidity providers such as 1inch, Uniswap, or Circle Cross-Chain Transfer Protocol (CCTP).
• Familiarity with GCC financial regulations (VARA, CBUAE) or RBI digital asset directives.
• Knowledge of containerized infrastructure including Docker, Kubernetes, AWS/GCP, Redis, and PostgreSQL.

What we offer

• Competitive salary package with performance bonuses and token/equity incentives.
• Opportunity to build a core product at the intersection of Web3 and global fintech.
• Relocation assistance for Dubai (if applicable) or remote flexibility.
• Collaborative engineering culture focused on ownership, security, and high performance.

Location

Based in or willing to relocate to Dubai, UAE or India. Flexible working arrangements available.