backend developer for wallet infrastructure

Rain is a global stablecoin payments platform for enterprises, neobanks, platforms, developers, and AI agents. It enables partners to move, store, and use stablecoins through global payment cards, rewards, on/offramps, wallets, and cross-border rails.

• Own the architecture of Rain's wallet infrastructure, designing secure, scalable systems for custody, key management, transaction signing, authorization, and recovery
• Design flexible signing infrastructure supporting MPC, HSMs, secure enclaves, TEEs, and emerging cryptographic approaches without creating fragmented systems
• Build and evolve wallet systems across account models, including 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 across the platform
• Architect security-critical key management systems for key generation, distributed key generation, storage, rotation, backup, recovery, and hardware-backed isolation
• Build highly available signing and transaction infrastructure to securely control high-value customer assets while maintaining reliable, developer-friendly APIs
• Set the 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, ensuring the architecture can evolve with new blockchain standards and cryptographic techniques

• Deep expertise in one or more areas of wallet, custody, cryptography, or security infrastructure, combined with strong distributed systems and architecture fundamentals
• Experience designing or building production wallet, custody, signing, or key management systems, particularly infrastructure responsible for securing high-value assets
• Strong knowledge of applied cryptography, such as 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, including EOAs, smart contract wallets, account abstraction, ERC-4337, transaction orchestration, and multichain systems
• Experience designing authentication, authorization, policy, permissions, recovery, or secrets-management systems where security and correctness are critical
• A 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 wallet or custody providers

• Unlimited vacation; Rainmakers are required to take at least 10 days off
• Flexible workplace: employees may work from home, from an office, or both
• New Rainmakers receive a stipend to set up a home workspace
• For US Rainmakers, the company covers 95% of health, dental, and vision plan costs and 90% for dependents, plus fully subsidized life insurance
• 401(K) with a 4% company match
• Every Rainmaker receives an equity option plan
• Monthly stipend for eligible health and wellness expenses
• Office-based Rainmakers receive lunch and dinner through a DoorDash credit
• Team and company offsites take place domestically and internationally