Senior Software Engineer, Ledger

Alt is unlocking the value of alternative assets, starting with the $5 B trading-card market. We let collectors buy, sell, vault, and finance their cards in one place and we are backed by leaders at Stripe, Coinbase, Seven Seven Six, and pro athletes like Tom Brady and Giannis Antetokounmpo. Our next frontier is real-time pricing at scale—the Alt Value that powers every trade, loan, and product on the platform.

The Role

A collector borrows against a card they own. We size the advance, disburse it, hold the collateral, and manage the loan for however long it runs. Meanwhile an auction closes and hundreds of payouts go out at once, each against a different fee schedule — some by ACH, some by wire, some instant. Every one of those movements has to land in a double-entry ledger that still balances at the end of the day.

That is the whole job. You own the ledger that is Alt's system of record, the money movement that feeds it, and the reconciliation that proves the two agree. You are not building a checkout flow. You are building the liquidity that makes this marketplace work.

The KPI: 99.99% reliability on gateway and banking integrations, and a ledger where every cent is accounted for and every entry says who created it and when. In payments, "mostly working" is a failure.

Financial correctness wants you to measure twice and cut once. The people who are great at this have owned a ledger somewhere it mattered, and they think in idempotency, race conditions, and reconciliation because they've been on the wrong side of all three.

What You'll Own

The ledger as system of record. Entries, lines, balances, holds, reversals, and the states in between — pending, posted, available, canceled, declined, reversed. Immutability and audit trail as design constraints, not features. Point-in-time balances that let a customer see where they stood on any past date. You should be able to spot a modeling error in a schema review before it becomes a six-month cleanup, and explain why a balance is a derived value and not a column.

Rails and money movement. ACH origination and returns, RTP and other instant rails, wires, cards, and stablecoin settlement. A $300K wire and a $300 ACH debit are different products with different controls, and you'll design for both. Credit-push rails change what you can auto-charge and when funds are final — you'll own those product consequences, not just the integration.

Payouts. Getting sellers and borrowers their money faster than anyone else in this market: instant payout options, batch payouts at auction close, and the settlement timing that makes them safe.

Reconciliation. When the ledger and the processor disagree, you own the answer. Automated matching, an exception queue that a human can actually work, and breaks caught before a customer finds them.

Lending infrastructure. Design and scale our lending products — credit disbursement through the automated lifecycle of loan management. Repayments, partial payments, advance reversals, state transitions, the loan that goes sideways.

Provider architecture. Multi-PSP integrations built so the next one isn't a rewrite, and readiness for a single orchestration layer if that's where we land. Webhooks, idempotency, retry semantics, state machines, failure modes on the third retry.

Risk on high-value flows. The fraud, dispute, and chargeback posture for a marketplace where one bad transaction is a five- or six-figure problem. Holds, limits, and settlement windows set with data — and you'll know what each one costs in conversion. Step-up verification triggered by risk signals rather than blanket friction.

Making it legible. The customer's account activity surface reads straight off your ledger: running balance, which method funded what, a full reconciliation of a single auction where someone both bought and sold. You'll ship some of that surface yourself, and you'll be the reason it's trustworthy.

The trade-off calls. Shipping speed against uncompromising correctness; build custom versus buy. You'll be asked to defend both directions.