Senior Backend Engineer (Fintech/Crypto)

About the opportunity

Arca.ph is recruiting a senior backend engineer for a small team building institutional digital-asset infrastructure. The platform connects custodians, cryptocurrency exchanges, and trading firms, supporting settlement and the reliable movement of financial information and assets. We are looking for an engineer who brings real financial-domain experience and can turn an ambiguous business problem into a safe, working production system. You should be able to explain what you built, why the financial workflow works that way, the decisions you made, and the business result

What you will do

• Build and operate backend services for settlement, post-trade workflows, and partner integrations, primarily in Python and Go.
• Integrate exchange, custodian, banking, and other partner APIs; identify gaps in vendor capabilities and design reliable workarounds.
• Model transactions, balances, positions, and financial events with clear consistency rules, auditability, and recovery paths.
• Protect financial correctness through transaction isolation, concurrency control, idempotent processing, reconciliation, and testing of failure scenarios.
• Work with blockchain integrations and understand on-chain protocol behavior, transaction confirmation and finality, and the constraints of coordinating activity across multiple chains.
• Own work from investigation and technical design through implementation, testing, deployment, monitoring, and production support.
• Contribute across the backlog, including infrastructure, compliance controls, and occasional React-based interfaces.
• Use Claude Code or comparable AI development tools effectively, while personally reviewing designs, testing behavior, and taking responsibility for the result.
• Explain integration architecture and tradeoffs to Product, business stakeholders, partner engineers, and customers

What you bring

• Senior-level experience personally owning substantial production backend systems, with specific examples of independent decisions and business impact.
• Professional experience building financial transaction systems, such as cryptocurrency exchange or custody infrastructure, settlement, post-trade, trading, banking, payments, risk, or accounting systems.
• Practical understanding of settlement, reconciliation, and financial data integrity; you can explain how your systems prevent lost, duplicated, or incorrectly recorded funds.
• Working knowledge of blockchain and digital-asset transaction mechanics, backed by professional project examples.
• Direct cryptocurrency exchange or custody experience is especially valuable.
• Strong backend engineering ability in Python or Go, or comparable production experience with a credible path to working in this stack.
• Strong relational data modeling and SQL skills, including transactions, consistency, and recoverability, plus familiarity with document databases.
• Ability to investigate unfamiliar domain problems, navigate an existing codebase, propose solutions, and raise focused questions without waiting for detailed implementation instructions.
• Clear professional English and the ability to explain complex financial and technical concepts simply.
• Comfort working remotely with a small, collaborative team during U.S. hours and taking responsibility for production outcomes

Especially useful experience

• PostgreSQL transaction isolation and locking; MongoDB; Go; React.
• on-chain protocols, multiple blockchains, custody or vault integrations, and on-chain/off-chain reconciliation.
• P&L, net positions, netting, counterparty risk, derivatives, prime brokerage, or bank back-office workflows.
• SOC 2 controls, secure development, audit trails, infrastructure as code, and operational reliability.
• Customer-facing integrations, architecture discussions, technical support, or pre-sales.
• Startup experience and a record of becoming productive quickly in a complex business domain.
• You do not need to be an expert in every specialty listed.
• Strong banking, trading, payments, or accounting experience can be relevant alongside practical blockchain understanding.
• We will focus on the systems you have owned and the judgment you bring

Working arrangement

This opportunity is open to anyone globally who is available to work U.S. hours. The team works remotely across time zones and shares production-support responsibilities