Senior Software Engineer

MoonPay is a high-standards, high-velocity company building infrastructure for the movement of value across crypto, stablecoins, tokenized assets, and related products. The Senior Software Engineer will design and operate scalable transaction, wallet, cross-chain, and DeFi infrastructure, while developing reliable backend services and supporting incident response, monitoring, and system resilience.

Responsibilities:

• Design and improve high-volume transaction broadcasting pipelines
• Manage transaction lifecycle
• Detect, retry, rebroadcast, and safely recover stuck transactions
• Contribute to wallet infrastructure and automation systems
• Implement safe parallel transaction handling
• Improve monitoring, observability, and operational guardrails
• Design systems with financial correctness and reconciliation and auditability in mind
• Build infrastructure supporting cross chain and multi step flows (fiat to on-chain and vice versa)
• Handle non-atomic multi-step journeys across chains
• Design state machines and recovery strategies for partial failure scenarios
• Support routing mechanics and swap execution considerations such as price impact, liquidity changes, including MEV awareness
• Build reliable off-chain services that interact with on-chain contracts
• Participate in estimation, planning, and execution of projects, features, and integrations
• Develop and maintain thoroughly tested, high-quality, and performant code
• Collaborate closely with Product Managers to design scalable implementation strategies
• Contribute to reliable, maintainable systems that evolve with product needs
• Participate in incident response and post-mortems
• Improve reliability, alerting, and system resilience
• Continuously evolve infrastructure to support growing volume and complexity

Requirements:

• Strong backend/platform engineering fundamentals
• Experience operating production systems with real uptime requirements
• Hands-on experience interacting with live blockchain networks in production
• Clear understanding of transaction lifecycle in at least 1 Blockchain and failure recovery
• You think in failure modes, not just happy paths
• You can explain a real production incident end-to-end
• Experience with at least 1 wallet infrastructure (Eth, Bitcoin, Solana) or custody systems
• Awareness of MEV, slippages, pricing impact and swap execution risks
• Experience with high-throughput or financial systems
• Experience working at exchanges, custody providers, wallet infrastructure teams, or high-volume DeFi platforms
• Familiarity with UTXO-based chains (e.g., Bitcoin), including coin selection and fee bumping strategies (RBF / CPFP)
• Experience designing cross-chain or multi-step transaction orchestration systems
• Familiarity with blockchain indexing or event ingestion pipelines
• Understanding of common token standards (ERC-20, SPL) and interacting with smart contracts from backend services