• Own the design and implementation of new on-chain primitives across both Ethereum and Solana, including staking flows, validator orchestration, vault strategies, exit and redemption mechanisms, and integrations with institutional custody. • Drive the audit lifecycle end to end: scoping, engaging audit firms, triaging findings, implementing remediations, and shepherding code to mainnet deployment. • Set and enforce the engineering bar within your team: testing standards, review processes, deployment runbooks, incident response, and on-call rotations for live contracts. • Partner with product and engineering leadership to translate enterprise-grade requirements — custody, compliance, settlement, operational controls — into on-chain designs that hold up to scrutiny from bank-grade counterparties. • Mentor smart contract engineers on your team and contribute to hiring, code review culture, and career development across the broader smart contract function. • Represent Galaxy's on-chain work externally where appropriate: with auditors, institutional clients, governance forums, and the broader Ethereum and Solana ecosystems. • Embrace and champion the thoughtful adoption of AI to improve team performance and business outcomes. • Leverage AI tools (e.g., generative AI, automation platforms, data copilots) to improve productivity, decision-making, and output quality in your day-to-day work.

Circle (NYSE: CRCL) is one of the world's leading internet financial platform companies, building the foundation of a more open, global economy through digital assets, payment applications, and programmable blockchain infrastructure. Circle's platform includes the world's largest regulated stablecoin network anchored by USDC, Circle Payments Network for global money movement, and Arc, an enterprise-grade blockchain designed to become the Economic OS for the internet. Enterprises, financial institutions, and developers use Circle to power trusted, internet-scale financial innovation. Learn more at circle.com . What you'll be part of: Circle is committed to visibility and stability in everything we do. As we grow as an organization, we're expanding into some of the world's strongest jurisdictions. Speed and efficiency are motivators for our success and our employees live by our company values : High Integrity, Future Forward, Multistakeholder, Mindful, and Driven by Excellence. We have built a flexible work environment where new ideas are encouraged and everyone is a stakeholder. What you'll be responsible for: We are looking for a Smart Contract Engineer to design, implement, test, and maintain production-grade smart contracts across multiple blockchain ecosystems. This role focuses primarily on EVM-based Solidity contracts and Solana programs written in Rust using the Anchor framework, while also building the backend services that power and integrate with those contracts. As a Smart Contracts Engineer, you'll be responsible for building secure and efficient smart contracts that power Circle's core protocols. You'll also contribute to the supporting backend services that enable transaction orchestration, indexing, and monitoring (70% smart contract development and 30% backend development). You will work closely with protocol, infrastructure, and security engineering teams to deliver high-assurance, auditable solutions that support scalable, blockchain-based services across ecosystems. What you'll work on: - Design and implement production-grade smart contracts across EVM and/or Solana ecosystems using Solidity and Rust - Develop backend services and integration layers that interface with deployed smart contracts and internal systems - Research and apply industry-standard design patterns and emerging best practices in smart contract and distributed systems engineering - Optimize smart contract performance, including gas efficiency, while enforcing strong security through secure architecture and defensive coding practices - Build and maintain transaction orchestration flows, event listeners, and indexing services that bridge on-chain and off-chain components - Test, deploy, and manage upgrades for smart contracts and backend services in production environments - Partner with security teams on audits, threat modeling, remediation, and production monitoring to ensure reliability and operational excellence What you'll bring to Circle: Core Requirements: - Proven experience designing and developing production-grade smart contracts in Solidity and/or Rust, with strong emphasis on security, gas optimization, and performance - Deep understanding of blockchain architecture, EIP standards, decentralized systems, and on-chain execution models - Strong knowledge of smart contract security principles and common vulnerability patterns (e.g., reentrancy, access control flaws, arithmetic errors) - Experience with smart contract development and testing frameworks such as Foundry, Hardhat, or Anchor - Working knowledge of backend development, particularly services that interact with blockchain networks (transaction submission, event processing, indexing) - Experience integrating smart contracts with backend systems and off-chain infrastructure - Experience designing and deploying production-grade, scalable cloud services in AWS, Google Cloud, Microsoft Azure, or similar environments - Strong collaboration skills with the ability to work cross-functionally with product, infrastructure, and security teams Preferred Requirements: - Experience shipping or operating multi-chain or cross-chain smart contract systems, with familiarity in Web3 fintech or DeFi environments - Experience contributing to or auditing open-source smart contracts or blockchain protocols - Experience developing smart contracts for non-EVM chains Circle is on a mission to create an inclusive financial future, with transparency at our core. We consider a wide variety of elements when crafting our compensation ranges and total compensation packages. Starting pay is determined by various factors, including but not limited to: relevant experience, skill set, qualifications, and other business and organizational needs. Please note that compensation ranges may differ for candidates in other locations. We are an equal opportunity employer. We do not discriminate on the basis of race, religion, color, national origin, gender, sexual orientation, age, marital status, veteran status, or disability status, or any other protected status required by the laws in the locations where we hire. Additionally, Circle participates in the E-Verify Program in certain locations, as required by law. Should you require accommodations or assistance in our interview process because of a disability, please reach out to accommodations@circle.com for support. We respect your privacy and will connect with you separately from our interview process to accommodate your needs. #LI-Remote

• Design and implement production-grade smart contracts across EVM and/or Solana ecosystems using Solidity and Rust • Develop backend services and integration layers that interface with deployed smart contracts and internal systems • Optimize smart contract performance, including gas efficiency, while enforcing strong security through secure architecture and defensive coding practices • Test, deploy, and manage upgrades for smart contracts and backend services in production environments

• Architect and implement core on-chain protocols for a Decentralized Exchange (DEX), including capital vaults, clearinghouses, and settlement engines. • Develop the underlying logic for clearing and settlement processes, ensuring high-fidelity integration with off-chain high-performance matching engines. • Design and maintain robust Oracle contract frameworks to support real-time price feeds, data validation, and asset valuation. • Lead smart contract security hardening initiatives, collaborate with external auditors to rectify vulnerabilities, and oversee mainnet deployments. • Partner with backend and QA teams to bridge the gap between off-chain trade commands and on-chain fund movements for seamless execution.