Senior Flutter Developer Jobs in Valley Stream, NY

Moonshot is the “Robinhood for DeFi”—an iOS and Android app that lets anyone trade cryptocurrencies on-chain through a user-friendly interface.

Since our launch in July 2024, we’ve attracted 2M+ users.

Our mission: Make moonshots possible for everyone.

Our vision: Make a world where life-changing financial outcomes are within everyone's reach.

Everyone on our team is both a decision-maker and an implementer—united by a sense of urgency and driven by the conviction that our work can transform global finance. If you thrive on curiosity, welcome tough challenges, and aspire to leave a meaningful mark on the world, Moonshot is the place for you. You’ll run toward the hardest problems alongside high-caliber teammates who consistently push each other to excel and who share your dedication to shaping the future of decentralized finance.

This role is full-time, preferably located in NYC. Open to remote for the right candidate.

As a Senior Backend & Platform Engineer at Moonshot, you’ll own some of the most critical systems in our stack: identity and access, funds movement and ledgering, and the blockchain infrastructure that powers our on-chain trading. This role is similar to staff engineers at leading crypto wallets and exchanges who own authentication stacks, key management, and high-scale financial backends. You’ll design, build, and operate systems that must be both highly reliable and extremely secure, enabling product teams to move quickly on a solid foundation.

• Design, build, and operate Identity & Access Management services:

  • Authentication flows, sessions, device trust.

  • Authorization and entitlements (roles, permissions, policies).

  • Security controls such as MFA and key management (working with security teams).

• Own financial operations systems:

  • Transfers and payments orchestration.

  • Ledgering and reconciliation flows.

  • Limits, risk controls, and transactional correctness.

• Build and maintain blockchain infrastructure:

  • Node and RPC management.

  • Transaction submission, monitoring, and retry logic.

  • Indexing and streaming of on-chain data into internal services and data stores.

• Define and uphold reliability and observability standards:

  • SLOs and error budgets for core services.

  • Dashboards, alerts, runbooks, and incident management practices.

• Lead large, cross-functional technical projects from design through rollout, collaborating with Product, Security, and Ops.

• Mentor and guide other engineers, contributing to engineering standards, design reviews, and documentation.

• Stay close to industry best practices in auth, key management, and secure infrastructure for crypto and trading.

• 5–12+ years of backend or product or platform engineering, including experience with high-scale, high-availability systems in fintech, crypto, or similar domains.

• Deep expertise in at least one of:

  • Identity & access / security engineering

  • Financial systems / ledgering / payments

  • Blockchain infrastructure / on-chain data

• Strong experience designing and operating distributed systems (datastores, queues, streaming, background workers).

• Track record driving architecture decisions and seeing them through implementation and adoption.

• Strong operational mindset: monitoring, on-call, incident response, and postmortems.

• Excellent collaboration skills, especially with Product, Security, and Ops.

• Experience with Flutter, React Native, React, Headless CRMs

• Experience with Go, Rust, Solana

• Experience with Google Cloud or Amazon Web Services

• Experience with crypto wallets, exchanges, or onchain protocols including DeFi, L2s, ZK

• Exposure to data warehousing and analytics for financial reporting.

• Contributions to open-source projects.

• NYC preferred (with periodic in-person sprints).

• Remote-friendly within the United States and Canada; travel ~1wk/quarter

• Competitive salary and meaningful equity.

• 5% 401(k) match.

• Health benefits with employer-covered premiums, plus life insurance coverage.

• One-time office setup stipend.

• Flexible PTO.