Senior/Staff Software Engineer

P2P; Lisboa; Presencial; EUR 90 000 - 140 000; Tempo integral

Resumo da oferta

Ethena is building a new engineering team to own a money-movement product. As the Staff/Senior Engineer, you’ll own money-path correctness and the core app APIs and authentication backend used by the mobile app.

Your north star is ensuring money moves correctly, exactly once, and securely, with fast, versioned, robust services. This is a senior IC role with design authority over the backend.

Qualificações

• Proven experience building backend systems that move real money in production across payments, settlement, banking, or crypto.
• Experience designing and owning client-facing APIs with versioning, idempotency keys, error models, pagination and rate limiting.
• Experience building or operating an authentication/authorization backend (OAuth2/OIDC, JWT, MFA/step-up), ideally with WebAuthn.
• Hands-on integration with financial partners end-to-end and reconciliation.
• On-chain settlement literacy and handling of nonces, gas, reorgs, and RPC failures.

Responsabilidades

• Design, build, and own complex backend systems for a high usage consumer app.
• Own the app-facing API contract as a product with versioning and consistent error handling.
• Own the authentication and authorization backend, including passkeys and session lifecycles.
• Defend the auth surface against abuse with rate limiting and secure handling of PII.
• Set patterns, tests, and docs to enable safe extension by other engineers.
• Trace and document money-paths end-to-end from API to on-chain settlement.
• Ship fast with test-driven and behaviour-driven development.

Conhecimentos

TypeScript

PostgreSQL

Event queues

gRPC

Backend design

API versioning

OAuth2/OIDC

WebAuthn

Idempotency design

Security best practices

Ferramentas

NATS

Kafka

SQS

Descrição da oferta de emprego

Role Overview

We're building a new engineering team at Ethena to own a money-movement product built on top of our stablecoin infrastructure. As the Staff/Senior Engineer, you own the correctness and evolution of the money-paths at the core of the product — payments, payouts, deposits, transfers, and reconciliation — and the app-facing APIs and authentication backend the native mobile app depends on.

Your north star: money always moves correctly, exactly once, and observably; and every request the app makes is fast, well-versioned, and secure. This is a senior IC role with real design authority over the backend — you set the standard for how these services are built, not just execute tickets.

Role Responsibilities

• Design, build, and own complex backend systems for a high usage consumer app.

• Own the app-facing API contract as a product: versioned, backward-compatible endpoints with client idempotency keys, a consistent error model, and clean pagination, built in partnership with the iOS team.

• Own the authentication and authorization backend, including the passkey/WebAuthn relying party, session/token lifecycle, and authorization enforcement at every API boundary.

• Defend the auth surface against abuse through rate limiting, anomaly detection, and secure handling of PII and secrets.

• Set patterns, tests, and documentation so the backend can be safely extended by any engineer, raising the correctness, testing, and security bar by example and in review.

• Trace and document money-paths end-to-end, from API through wallet/executor/submitter/indexer, event streams, and on-chain settlement, closing real correctness and reliability gaps as you go.

• Ship fast, test-first. Deliver on a tight cadence with test-driven and behaviour-driven development — you can prove the correctness of a payout path, not just its happy path.

Required Skills and Experience

• Proven experience building and operating backend systems that move real money in production — payments, exchange/settlement, lending, banking, or crypto — with a track record of preventing (or fixing) idempotency, rounding, or reconciliation bugs.

• Experience designing and owning client-facing APIs consumed by a mobile app at scale: contracts, versioning and backward compatibility, idempotency keys, error models, pagination, and rate limiting.

• Experience building or operating an authentication/authorization backend — OAuth2/OIDC, JWT session/token lifecycle, RBAC/ABAC scopes, MFA/step-up — ideally including a WebAuthn/passkey relying party.

• Hands-on integration with real financial third parties end-to- end (card issuing, KYC/fiat ramp partners, or payments/settlement providers), including their webhooks, failure modes, and reconciliation.

• On-chain settlement literacy from the backend — nonces, gas, reorgs, RPC failure, confirmation depth — treating chain data as untrusted input.

• Strong TypeScript (or a fast, credible path from Go/Kotlin/Rust/Java), with Postgres, an event/queue system (NATS/Kafka/SQS-class), and gRPC-based service-to-service communication at production scale.

• A test-first culture matching ours — BDD/integration testing with real dependencies (Testcontainers-style) — and fluency with agentic development workflows (Claude Code, MCP, skills) as a core part of how you engineer.