Blockchain Engineer

Remote (U.S.) — Full Time

The Cari Network is building a blockchain-based payment system powering real-time, 24/7 movement of digital money across the traditional finance and digital asset ecosystems. A pre-launch startup, we're creating an entirely new category of financial infrastructure that brings cash on chain through tokenization while powering the full spectrum of payments for our network—banks, digital asset exchanges, and, most importantly, the customers they serve.

About the Role

You'll own the systems that take a payment instruction and turn it into an immutable, on-chain record. That means designing and extending the integration layer between our backend services and our institutional custody platform, ensuring transaction integrity from calldata construction through on-chain finality on our private ZKsync-based L2.

You'll also work directly on our smart contract suite, maintaining upgrade safety, on-chain event integrity, and audit trails that satisfy the compliance and evidentiary requirements of regulated bank partners.

What You'll Do

  • Own the end-to-end transaction lifecycle: calldata construction, custody platform signing requests, nonce management, L2 submission, and finality confirmation

  • Design and implement the signing pipeline architecture — including parallelization strategies, throughput management against custody platform rate limits, and async transaction submission patterns

  • Build and maintain payment integrity controls: commitment hash verification at pipeline handoff points and co-signer policy evaluation to prevent tampering between transaction origination and on-chain execution

  • Extend and harden our Solidity smart contracts with a focus on upgrade safety, storage layout discipline, and role governance

  • Develop and maintain a custody platform authorization policy integration and co-signer agent for custodian-owned transaction authorization

  • Implement structured audit trails from transaction origination through on-chain execution, satisfying evidentiary requirements for bank partners under regulatory oversight

  • Contribute to the design of an async transaction queue, enabling tiered SLAs and per-bank throughput quotas at scale

  • Write high-coverage tests across backend services and smart contracts, maintaining our coverage threshold

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 signing pipelines

  • Prior work in fintech, payments, or any regulated financial infrastructure environment

  • Experience building or operating blockchain event indexers or transaction monitors

  • Foundry proficiency (forge test, forge fmt, Foundry Upgrades for storage layout validation)

Qualifications

  • 5+ years of backend software engineering experience, with at least 2 years working directly on EVM-compatible blockchain systems

  • Strong proficiency in TypeScript; experience with Effect (effect.ts) or a comparable functional effect system is highly valued

  • Deep familiarity with EVM transaction mechanics: ABI encoding, nonce management, gas estimation, revert handling, and event decoding

  • Production experience with Solidity smart contract development, including upgradeable proxy patterns (UUPS preferred) and OpenZeppelin contract libraries

  • Experience integrating with institutional custody or key management APIs (Fireblocks, Turnkey, Fordefi, or similar)

  • Understanding of MPC signing infrastructure and the operational model of custodial signing pipelines

  • Strong instincts around financial-grade reliability: idempotency, at-least-once delivery, crash recovery, and reconciliation in async transaction systems

  • Comfortable operating with high autonomy in a small, fast-moving team where the architecture is still being defined

What We Offer

  • Competitive compensation

  • 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

Interested in this role? Send us your resume.

‹ Client Support Engineer

Recruiter ›