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Rain is a global stablecoin payments platform serving enterprises, neobanks, platforms, developers, and AI agents. The company enables partners to move, store, and use stablecoins instantly and compliantly through global payment cards, rewards, on/offramps, wallets, and cross-border rails. As a Visa and Mastercard Principal Member, Rain issues cards accepted at 175+ million merchant locations across 220+ countries. The company raised $250M in Series C funding in January 2026 (led by ICONIQ, valuing the company at $1.95B) and is trusted by 100+ organizations.
You will own the architecture of Rain's wallet infrastructure, designing secure, scalable systems for custody, key management, transaction signing, authorization, and recovery. Key responsibilities include:
• Design flexible signing infrastructure supporting MPC, HSMs, secure enclaves, TEEs, and emerging cryptographic approaches without fragmentation
• Build and evolve wallet systems across multiple account models: EOAs, smart contract wallets, account abstraction, ERC-4337, embedded wallets, and multichain infrastructure
• Define boundaries between cryptography and wallet orchestration, including how keys, signing authority, transaction policies, permissions, and authorization interact
• Architect security-critical key management systems covering generation, distributed key generation, storage, rotation, backup, recovery, and hardware-backed isolation
• Build highly available signing and transaction infrastructure capable of securely controlling high-value customer assets while maintaining reliable, developer-friendly APIs
• Set technical direction for wallet security, including threat modeling, policy engines, secrets management, account recovery, authentication, and programmable authorization
• Make foundational build-vs.-buy decisions across cryptography, custody, wallet, and security infrastructure
Rain operates with a flat, open structure where team members at all levels have freedom to explore ideas and impact the roadmap. The company offers flexible working arrangements (remote, office, or hybrid), unlimited time off (minimum 10 days required), home workspace stipend, comprehensive health/dental/vision coverage (95% for employees, 90% for dependents), 401(k) with 4% match, equity options for all employees, monthly health and wellness stipend, in-office meals via DoorDash credit, and regular team summits.
REQUIREMENTS:
• Deep expertise in one or more areas of wallet, custody, cryptography, or security infrastructure, combined with strong distributed systems and architecture fundamentals
• Production experience designing or building wallet, custody, signing, or key management systems, particularly infrastructure responsible for securing high-value assets
• Strong knowledge of applied cryptography: MPC, threshold cryptography, threshold signatures, distributed key generation, ECDSA, EdDSA, or secure multiparty computation
• Experience with HSMs, secure enclaves, TEEs, confidential computing, hardware-backed key isolation, or other security-critical infrastructure
• Strong understanding of modern wallet and blockchain account architecture: EOAs, smart contract wallets, account abstraction, ERC-4337, transaction orchestration, multichain systems
• Experience designing authentication, authorization, policy, permissions, recovery, or secrets-management systems where security and correctness are critical
• Track record of making high-leverage architectural decisions in complex distributed systems, evaluating tradeoffs across security, reliability, developer experience, and extensibility
• Ability to form strong technical opinions, communicate tradeoffs clearly, and own architecture from first principles through production rather than simply integrating existing providers
