Software Engineer, Blockchain

HIFI•New York, NY

1d•Onsite

About The Position

HIFI is a stablecoin infrastructure company building technology for financial products, including payments and tokenized money products across money movement, cards, and capital markets. The company’s engineering team builds APIs, ledger, and on-chain systems used by fintechs and financial institutions to move money on stablecoin rails. The Blockchain Engineer will help own HIFI’s on-chain systems day to day, building and maintaining integrations, smart contracts, and wallet infrastructure connecting payment products to supported blockchains and stablecoins. The role includes designing on-chain funds movement and settlement, integrating those flows with the company’s ledger and APIs, partnering with compliance on controls, and evaluating whether new chains or protocols are production-ready. The position requires working in person at HIFI’s Flatiron office most days of the week, within commuting distance.

Requirements

At least 3 years of software engineering experience, including at least 1 to 2 years building blockchain systems in production.
Deep familiarity with EVM chains, including transaction lifecycles, gas mechanics, and common failure modes.
Enough Solidity knowledge to read and integrate contracts.
Experience with wallet architecture, such as custody models, signing services, or MPC- and HSM-backed setups.
Strong backend fundamentals, including API design, data modeling, and handling consistency and concurrency in distributed systems.
Build financial systems with reconciliation and audit trails by default.
Communicate clearly in code review and in writing.
Must be within commuting distance of the office and able to work in person most days of the week.

Nice To Haves

Experience with stablecoin infrastructure such as Circle, or connecting on-chain and fiat settlement.
Hands-on experience with CEX APIs, DEX protocols such as Uniswap, or bridge integrations.
Experience building ledgers or double-entry accounting systems.
Exposure to compliance engineering, such as transaction monitoring, address screening, or Travel Rule tooling.
Experience with non-EVM chains such as Solana or Tron.
Familiarity with traditional money movement, including ACH, wires, and settlement between banks and processors.
Early-stage startup experience building and running a system from scratch.

Responsibilities

Build wallet infrastructure, including key management, transaction signing, and orchestration across custodial and programmatic wallets.
Handle on-chain transactions across EVM chains and other supported networks, including gas, nonce management, and retries.
Build stablecoin minting, burning, and settlement logic connecting USDC and other stablecoins to fiat rails for on-ramp and off-ramp products.
Integrate centralized and decentralized exchanges for swaps and liquidity routing, and implement cross-chain bridging.
Build a double-entry ledger that synchronizes on-chain balances, banking partners, and customer accounts, with automated reconciliation.
Build event listeners, confirmation tracking, and webhooks to provide real-time visibility into on-chain activity.
Create idempotent transaction pipelines with failure recovery and screening hooks.
Work with engineering to connect on-chain flows to the ledger and APIs.
Partner with compliance on controls such as wallet screening and transaction monitoring.
Assess whether new chains or protocols are ready for production use.