Senior/Staff Software Engineer

Ethena Labs is seeking a Senior/Staff Software Engineer to lead the development of a money-movement product. This remote role focuses on backend systems, APIs, and authentication for a high-usage consumer app. We’re building a new engineering team at Ethena to own a money-movement product built on top of our stablecoin infrastructure.

• •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.

• •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.