Senior Backend Software Engineer — Fintech, Credit & Payments

Asystem; New York (NY); On-site; USD 150,000 - 190,000; Full time

Job summary

Arch is hiring a Senior Backend Software Engineer to design, build, and operate core financial systems behind a modern credit and lending platform. You’ll own backend services for credit, payments, and accounting workflows, operating where traditional rails meet crypto infrastructure.

Correctness, observability, and resilience are non-negotiable. You’ll work on money movement, ledgering, and stateful financial systems with high ownership and impact, collaborating with frontend teams using

Qualifications

• 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.

Responsibilities

• 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 with frontend engineers using Next.js, exposing stable HTTP APIs.
• Contribute to technical design reviews and lift backend engineering quality.

Skills

Backend engineering

Fintech experience

Ledgering systems

Event-driven architectures

Idempotency

HTTP services

Postgres knowledge

Redis usage

Observability

Tools

Postgres

Redis

AWS Lambda

Serverless Framework

Next.js

Job description

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