Reins - Fullstack Engineer
Reins is building an enterprise stablecoin account that looks and feels like a first-class business bank account, while giving companies the benefits of stablecoin rails and self-custody. Reins makes stablecoins operationally simple for businesses, providing familiar banking features such as ACH, wires (and global equivalents like SEPA), cards, multi-level permissions, approvals, and AML/compliance workflows—combined with stablecoin-native advantages like instant 24/7 global settlement, better control via self-custody, and access to lending, insurance, and exchange markets as DeFi infrastructure matures. Role Overview You’ll work directly with founder and CEO Sebastian Delgado (co-founder of Fei Labs), taking ownership of meaningful chunks of backend, full-stack, and security work. The role is flexible:
- Full-stack engineer (preferred)
- Backend engineer
- Product/frontend contributor (optional)
Focus areas are prioritized as follows: security & smart contracts, full-stack, backend, and product/frontend. Infrastructure/devops is not a current priority. Backend & Integrations
- Design and build backend services connecting custody, fiat rails, policies, and operational workflows
- Implement and maintain APIs and services for ACH, wires, cards, permissions, AML/compliance workflows, and reporting
Smart Contracts & Security
- Implement and review Solidity smart contracts, focusing on correctness, safety, and upgradeability
- Contribute to threat modeling, security reviews, and audit/vendor management
Product & Full-Stack Work
- Collaborate on the design and implementation of customer-facing applications (currently Dart/Flutter)
- Translate user and operational needs into product and UX decisions, especially around permissions, approvals, and money flows
Security & Audit Participation
- Own parts of audit/security review processes for your areas of the stack
- Coordinate with external security firms
- Build internal systems and processes with a security-first mindset appropriate for handling customer funds
- Strong background as a backend or full-stack engineer, ideally in early-stage fintech (Plaid, Brex, Ramp, modern neobanks)
- Experience with crypto infrastructure, wallets, or stablecoin projects
- Proficiency in Solidity smart contracts or a willingness to contribute to security-critical logic
- Familiarity with APIs, integrations, and operational workflows (ACH, wires, cards, permissions, AML/compliance)
- Ability to collaborate on frontend/product work is a plus (Dart/Flutter experience beneficial)
- Strong understanding of security best practices for handling customer funds
- Excellent problem-solving, attention to detail, and autonomy in early-stage environments
Preferred Backgrounds
- Early engineers at crypto infra/wallet/stablecoin companies
- Strong backend/full-stack engineers from top fintechs who are crypto-native
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