Senior Backend Software Engineer — Fintech, Credit & Payments

Arch 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 state
• Own and evolve ledgering systems that track balances, interest, and obligations with strong invariants
• Design event-driven architectures and orchestration workflows across asynchronous services
• Build idempotent APIs, consumers, and jobs to safely handle retries, replays, and partial failures
• Model and persist financial data in Postgres , with careful use of transactions and migrations
• Use Redis for caching, locking, and coordination in distributed workflows
• Define and evolve service boundaries within a microservices architecture
• Ensure systems are observable in production via structured logging, metrics, and tracing
• Operate services end-to-end: deploy, monitor, debug, and improve reliability
• Collaborate closely with frontend engineers using Next.js , exposing clean and stable HTTP APIs
• Contribute to technical design reviews and help raise the bar for backend engineering quality

Our Stack

• Backend: AWS Lambda (Node.js / TypeScript), Serverless Framework
• Frontend: Next.js (TypeScript)
• Datastores: Postgres, Redis
• Architecture: Event-driven (Inngest), microservices
• Infra / Ops: AWS (IAM, S3, RDS, CloudWatch), CI/CD
• Observability: Structured logs, metrics, distributed tracing

What We’re Looking For

Required

• 5+ years of backend engineering experience, with direct fintech experience
• Strong background in credit, lending, or financial systems
• Hands‑on experience with ledgering or accounting‑style systems
• Experience designing event‑based systems and asynchronous workflows
• Deep understanding of idempotency in APIs and distributed processing
• Strong knowledge of HTTP services and service-to-service communication
• Production experience with Postgres (schemas, transactions, migrations)
• Experience using Redis in distributed systems
• Comfort operating and debugging production systems
• Strong systems thinking and attention to correctness and edge cases

Strong 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 stacks
• DevOps or infrastructure experience, especially in AWS
• Comfort standing up new services from scratch and owning them in production
• Familiarity with serverless architectures and AWS Lambda
• Experience building systems that must tolerate eventual consistency and failure

What Success Looks Like

• You design systems with correctness as the first priority
• You think in terms of events, invariants, and state transitions
• You proactively identify edge cases and failure modes before they ship
• You leave systems more observable and reliable than you found them
• You take ownership beyond code—through deployment, monitoring, and iteration

Why Join Us

• Build real financial infrastructure with meaningful complexity and impact
• Work at the intersection of credit, payments, and crypto
• High ownership and influence over core backend architecture
• Engineering culture that values rigor, clarity, and production excellence