Senior Backend Engineer

At Offchain, we aren’t just building products: we’re leading a movement. We’re pioneers in blockchain scalability and security, at the forefront of transforming how the world interacts with decentralized applications. Our team is made up of thinkers and doers who embrace new challenges and seek solutions that push boundaries. If you’re energized by solving unprecedented problems and believe in decentralized systems, we want to hear from you. Why Offchain? Offchain is setting the pace for the Ethereum ecosystem. We built the Arbitrum stack powering Arbitrum One, with hundreds of projects and dApps using Offchain technology to build their own Arbitrum chains. We’re backed by $124 million in funding and have shipped billions in value. The Role: The Developer Platform team builds KMS, the key-management and signing service behind ZeroDev's non-custodial wallets. You’ll own production Go services and cryptographic recovery and trust-model systems, in a small high-ownership team. This is security-critical infrastructure with external audits. You should be comfortable with applied-cryptography fundamentals like public-key cryptography, signatures and key management. You don’t need to be a cryptographer or have prior experience with areas like MPC or TEEs, but you should be able to reason about cryptographic systems and their security implications. As the platform evolves, you'll also help expand it beyond interactive consumer wallets toward programmatic and automated signing, and programmable transaction policies. What you'll work on:: Backend services: build and operate Go services that power wallet creation, authentication, and signing at scale Key recovery and the committee trust model: distributed key generation and secret sharing that keep the service non-custodial, with recovery authority split across independent committees so no single party holds a user's key Trusted Execution Environments: reconstructing and operating on key material under hardware isolation and remote attestation Authentication and signing-provider integration: the user-facing auth methods that gate signing (passkeys / WebAuthn, OAuth, OTP, sessions, 2FA), and integrating with a third-party signing provider (authorization and policy flows, scoped credentials, quorum / consensus approvals) Security review and hardening: writing design docs and decision records, working directly with external security auditors, and turning a high review bar into shipped code Production operations on Kubernetes: observability and alerting, secrets and certificate management, on-call, and the compliance controls the domain requires (sanctions screening, PII-safe handling) Who you are:: Strong backend engineer who has shipped and operated production services in Go (or an adjacent systems language and is eager to go deep in Go) Security-first by default: You naturally think about threat models, blast radius and key custody, and write code that holds up to security-critical review Comfortable with applied-cryptography: You understand fundamentals such as public-key cryptography, signatures and key management, and can reason about how they apply to production systems. You don't need to be a cryptographer! Solid on distributed systems and API design: You’re comfortable reasoning about idempotency, failure modes and clean service boundaries Operationally experienced: You’ve worked with production infrastructure and are comfortable with Kubernetes, observability and incident response Clear written communicator: You can explain technical decisions through design docs and decision records, and work effectively in a collaborative, review-heavy environment. Nice-to-have You don't need to have worked with all of these. Experience in one or more would be valuable. Trusted Execution Environments (TEE) such as AWS Nitro Enclaves, Intel SGX / TDX or similar Threshold cryptography / MPC, including DKG, FROST or other threshold signatures, verifiable secret sharing or resharing Account abstraction, including ERC-4337, EIP-7702, smart accounts or embedded / non-custodial wallets Custody or signing infrastructure such as Turnkey or Fireblocks, either as an integrator or builder HSMs, YubiKey / PIV or secure-element integrations Third-party security audits and driving remediation through to completion Authentication technologies such as WebAuthn / passkeys and OAuth / OIDC, or experience with the Go crypto ecosystem Perks:: Remote-first global workforce + NY office Professional reimbursement program (facilitates industry conference attendance, certifications, and more) Medical, dental & vision coverage (US + some other countries) 401k retirement plan + company match (US only) Wellness stipend Home office set up / ergonomic equipment program Attention Offchain Job Seekers: This role cannot be performed in California, or Colorado. Please be advised that there has been a rise in fraudulent recruiter activities, particularly within the Web3 space. If you would like to confirm whether someone is an Offchain employee or the legitimacy of an offer you received, please email jobs@offchainlabs.com At Offchain, we are committed to building a welcoming and supportive workplace for all employees, regardless of their background or identity. We strive to create an environment where everyone feels valued and has an equal opportunity to succeed and thrive. We encourage candidates from all walks of life to apply and join our team.

The text above is the employer's original job description, extracted as written. Other details on this page, like salary, responsibilities, and requirements, are interpreted from that text by our system, not values the employer explicitly confirmed, so treat them as our best interpretation rather than verified facts.