Senior Software Engineer

Senior Backend Software EngineerArch is a U.S.-based, regulated digital-asset lending platform providing over-collateralized loans backed by Bitcoin and other major cryptocurrencies. We serve high-net-worth individuals, businesses, miners, funds, and family offices seeking liquidity without selling long-term crypto holdings. Arch is ranked as the safest centralized (CeFi) crypto lender, reflecting our conservative risk management, qualified custody model, and strict no-rehypothecation policy. We operate with institutional-grade legal, operational, and compliance standards built to perform across market cycles.Arch maintains excellent Trustpilot ratings from hundreds of verified users, underscoring our transparency, execution quality, and white-glove client experience. Since launch, Arch has originated hundreds of millions of dollars in loans and continues to scale through new products, structured financing, and partnerships across crypto-native and traditional financial markets. We are a small, high-ownership team that values precision, speed, and accountability—and we take pride in building durable financial infrastructure.About the Role:Arch is hiring a Senior Backend Software Engineer to help design, build, and operate the core financial systems behind a modern credit and lending platform. This role is for an experienced engineer who is comfortable working on money movement, ledgering, and stateful financial systems, and who understands the rigor required when software directly impacts balances, obligations, and risk.You'll take meaningful ownership over backend services that power credit, payments, and accounting workflows, operating in an environment that blends traditional financial rails with crypto and stablecoin infrastructure. Correctness, observability, and resilience are non-negotiable.What You'll Do:Design and implement core backend services for lending, payments, and account stateOwn and evolve ledgering systems that track balances, interest, and obligations with strong invariantsDesign event-driven architectures and orchestration workflows across asynchronous servicesBuild idempotent APIs, consumers, and jobs to safely handle retries, replays, and partial failuresModel and persist financial data in Postgres, with careful use of transactions and migrationsUse Redis for caching, locking, and coordination in distributed workflowsDefine and evolve service boundaries within a microservices architectureEnsure systems are observable in production via structured logging, metrics, and tracingOperate services end-to-end: deploy, monitor, debug, and improve reliabilityCollaborate closely with frontend engineers using Next.js, exposing clean and stable APIsContribute to technical design reviews and help raise the bar for backend engineering qualityOur Stack:Backend: AWS Lambda (Node.js / TypeScript), Serverless FrameworkFrontend: Next.js (TypeScript)Datastores: Postgres, RedisArchitecture: Event-driven (Inngest), microservicesInfra / Ops: AWS (IAM, S3, RDS, CloudWatch), CI/CDObservability: Structured logs, metrics, distributed tracingWhat We're Looking For:5+ years of backend engineering experience, with direct fintech experienceStrong background in credit, lending, or financial systemsHands-on experience with ledgering or accounting-style systemsExperience designing event-based systems and asynchronous workflowsDeep understanding of idempotency in APIs and distributed processingStrong knowledge of services and service-to-service communicationProduction experience with Postgres (schemas, transactions, migrations)Experience using Redis in distributed systemsComfort operating and debugging production systemsStrong systems thinking and attention to correctness and edge casesStrong Plus:Experience with payments rails, including:Traditional rails (ACH, wires, cards, etc.)Crypto or stablecoin rails (USDC, on-chain transfers, custodial flows)Experience working with crypto-native infrastructure or hybrid fintech/crypto stacksDevOps or infrastructure experience, especially in AWSComfort standing up new services from scratch and owning them in productionFamiliarity with serverless architectures and AWS LambdaExperience building systems that must tolerate eventual consistency and failureWhat Success Looks Like:You design systems with correctness as the first priorityYou think in terms of events, invariants, and state transitionsYou proactively identify edge cases and failure modes before they shipYou leave systems more observable and reliable than you found themYou take ownership beyond code—through deployment, monitoring, and iterationWhy Join Us:Build real financial infrastructure with meaningful complexity and impactWork at the intersection of credit, payments, and cryptoHigh ownership and influence over core backend architectureEngineering culture that values rigor, clarity, and production excellence