Blockchain Engineer

Summary

Cari Network is building a blockchain-based payment system for real-time movement of digital money across traditional finance and digital asset ecosystems. The Blockchain Engineer will implement transaction lifecycle components, extend Solidity smart contracts, integrate custody authorization systems, build audit trails and compliance evidence, and maintain reliable asynchronous payment pipelines.

Responsibilities

• Implement components of the transaction lifecycle: calldata construction, custody platform signing requests, nonce handling, L2 submission, and finality confirmation, working within the pipeline architecture senior engineers on the team have designed
• Build features within the signing pipeline—new submission paths, throughput handling against custody platform rate limits, async transaction submission logic—under existing architectural patterns
• Implement payment integrity controls: commitment hash verification at pipeline handoff points and co-signer policy evaluation logic
• Extend our Solidity smart contracts, following established upgrade-safety, storage-layout, and role-governance conventions
• Contribute to the custody platform authorization policy integration and co-signer agent for custodian-owned transaction authorization
• Build structured audit trail logging from transaction origination through on-chain execution, satisfying evidentiary requirements for bank partners under regulatory oversight
• Contribute to the async transaction queue supporting tiered SLAs and per-bank throughput quotas
• Write high-coverage tests across backend services and smart contracts, maintaining our coverage threshold
• Participate in on-call, working through known issue patterns independently and escalating novel failure modes to senior engineers

Skills

• 3–5 years of backend software engineering experience, with 1–2 years working directly on EVM-compatible blockchain systems
• Solid proficiency in TypeScript; familiarity with Effect (effect.ts) or a comparable functional effect system is a plus
• Working familiarity with EVM transaction mechanics: ABI encoding, nonce management, gas estimation, revert handling, and event decoding
• Some production experience with Solidity smart contract development, including exposure to upgradeable proxy patterns (UUPS) and OpenZeppelin contract libraries
• Exposure to institutional custody or key management APIs is a strong plus, though not required
• Understanding of idempotency, at-least-once delivery, and crash recovery concepts in async systems
• Comfortable asking for help extending existing patterns while building toward independent ownership of larger features
• Experience with ZKsync or ZK Stack-based chains—particularly developer-facing constraints like calldata handling, system contract interactions, and AA transaction formats
• Familiarity with Kafka or message-queue-backed async pipelines
• Prior work in fintech, payments, or any regulated financial infrastructure environment
• Foundry proficiency (forge test, forge fmt)

Qualifications

Must Haves

• 3–5 years of backend software engineering experience, with 1–2 years working directly on EVM-compatible blockchain systems
• Solid proficiency in TypeScript; familiarity with Effect (effect.ts) or a comparable functional effect system is a plus
• Working familiarity with EVM transaction mechanics: ABI encoding, nonce management, gas estimation, revert handling, and event decoding
• Some production experience with Solidity smart contract development, including exposure to upgradeable proxy patterns (UUPS) and OpenZeppelin contract libraries
• Exposure to institutional custody or key management APIs is a strong plus, though not required
• Understanding of idempotency, at-least-once delivery, and crash recovery concepts in async systems
• Comfortable asking for help extending existing patterns while building toward independent ownership of larger features

Nice to Haves

• Experience with ZKsync or ZK Stack-based chains—particularly developer-facing constraints like calldata handling, system contract interactions, and AA transaction formats
• Familiarity with Kafka or message-queue-backed async pipelines
• Prior work in fintech, payments, or any regulated financial infrastructure environment
• Foundry proficiency (forge test, forge fmt)

Benefits

• Remote-first work environment
• Opportunity to shape a market-defining protocol with an experienced founding team
• Meaningful influence over product design at the earliest stage