
Senior Backend / Product Engineer — Fintech (Lending & Ledger)
• Software
Compensation
$5,000–$10,000/month
Job Description
We're a small team building a live consumer credit product — a dynamic credit card: application funnel, KYC/credit decisioning, a double-entry ledger, statements, payments, and ACH. You'll own backend systems where correctness with money is the whole job. You'll help shape the product itself as well. You need strong product judgement.
You'll work on
- Services that move money and reconcile against a ledger that is the system of record
- Integrations with credit-decisioning, card-issuing, ACH, and KYC/AML providers
- Cross-service contracts (async, queue-based) where a malformed message is a production incident
- GraphQL APIs powering a mobile app, plus the batch/job pipelines behind statements and payments
- Product design and implementation across the member experience, from application flow through servicing and repayment
Must have
- Strong backend fundamentals: data modeling, Postgres, async/queue-driven systems, idempotency, and designing for failure
- Comfort owning a feature across the stack: DB → API → infra → tests → deploy → monitoring
- The ability to operate with incomplete requirements and drive a problem to a concrete outcome
Strongly preferred
- Financial/fintech experience — ledgers, double-entry accounting, payments/ACH, lending, or card issuing. You understand why "close enough" is a bug.
- Product-engineer instincts — you scope from the user's problem, not just the ticket; you push back on unnecessary work, challenge assumptions, and cut features that don't pull their weight
- Experience building products in a startup environment where engineers are expected to contribute to both product direction and implementation
Nice to have
- Elixir / Phoenix / Absinthe / Oban (or genuine enthusiasm to ramp — strong Ruby/Erlang/functional folks adapt fast)
- AWS (we use CDK), infra-as-code, observability (Datadog)
- Experience with regulated/compliance-sensitive systems (PCI, KYC/AML, Reg B)
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Job Details
- Category
- Software
- Employment Type
- Full Time
- Location
- Warsaw, Poland (Hybrid)
- Posted
- Compensation
- $5,000 - $10,000 per month
About Pesto
Pesto is a fintech startup that offers Pesto Mastercard, an asset-backed secured credit card. Pesto Mastercard is making credit more affordable, even if you don’t have an excellent credit history or a good credit score.
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