Senior Security Engineer, DeFi
Senior Security Engineer protecting the Sui DeFi ecosystem: building continuous security/economic-risk monitoring, hunting critical vulnerabilities in high-TVL protocols, running compliance cycles, and serving as security point of contact for external DeFi teams and Mysten products like DeepBook. Core stack includes TypeScript, Python, Rust, SQL, and blockchain data/indexing tools.
- Compensation
- $165K–$225K / yr
- Location
- USA (Remote)
- Work setup
- Remote
- Seniority
- Senior
- Employment
- Contract
- Experience
- 3+ years
- Category
- Security
- Posted
Skills
Must have
- Bachelor's degree in Computer Science, Computer Engineering, a relevant technical field, or equivalent practical experience
- 3+ years hands-on experience in security engineering, smart contract security, or DeFi risk engineering, with production tools built and real vulnerabilities found (audits, bug bounties, research, inc
- Strong understanding of DeFi mechanics and failure modes: lending markets, AMMs and concentrated liquidity, perpetuals, liquid staking, oracles, flash loans, MEV
- Proficiency in TypeScript and Python, comfort with Rust, ability to write SQL over large datasets, and work with blockchain indexers and data warehouses
- Experience reading smart contract code at source, bytecode, or disassembly level, or evident ability to learn quickly (Move a plus; Solidity or Rust smart contract experience transfers)
- Rigor: verify claims against bytecode and chain state, build known-clean checks into tools, and state what was not verified
- Strong written and verbal communication, including influencing external teams without formal authority
- Interest in the web3 space
Nice to have
- Sui and Move experience: object and capability model, package upgrades and version gates, programmable transaction blocks, Sui GraphQL and gRPC APIs
- Knowledge of recent DeFi exploit history on Sui and other chains, including named incidents, oracle compromises, and defect classes
- Experience building analysis or monitoring tools with LLM agents (Claude Code skills or comparable)
- Static or dynamic program analysis experience: taint analysis, call graphs, symbolic execution, fuzzing, formal verification
- Quantitative or economic modeling experience: stress testing, liquidity modeling, risk parameters for lending markets
- Publications, conference talks, CVEs, or bug bounty rankings
Full description
Mysten Labs’ mission is to advance the internet through step-function improvements in what technology makes possible. We build foundational infrastructure and products that give people, businesses, and developers new ways to interact, transact, and create value.
Our work spans on-chain finance and the emerging agent economy. Through Sui, Move, and our broader technology stack, we’re building the systems that make these experiences possible - from secure, scalable blockchain infrastructure to new ways for businesses and AI agents to interact.
We’re looking for a Senior Security Engineer to help protect the Sui ecosystem. You’ll uncover vulnerabilities, build monitoring tools, and assess economic risk across DeFi protocols. Working closely with external protocol teams and Mysten’s own DeFi products, including DeepBook, you’ll help address risks before they become incidents and strengthen security across the ecosystem
Responsibilities
- Build and run continuous monitoring of the Sui DeFi ecosystem for security and economic risk: oracle issues, misconfigurations/bad economic parameters, solvency and bad-debt exposure under price shocks, liquidation capacity against on-chain liquidity depth, accounting-versus-positions reconciliation, invariants.
- Extend security team tooling, both precise static analysis tooling and proprietary agent skills.
- Measure and drive compliance with the DeFi security recommendations across supported protocols: run the recurring compliance cycle, fill the protocol report card, validate security claims (audits, custody, upgrade governance, oracle dependencies) against on-chain reality, track remediation commitments, and escalate when a protocol regresses or fails to disclose an incident. Partner with the ecosystem and finance owners of the process.
- Hunt for critical vulnerabilities in the highest-TVL Sui protocols and get them fixed before they are exploited: full-package audits, variant analysis across forks, pre-execution review of multisig upgrade payloads, and forensics after incidents anywhere in the ecosystem.
- Be the security team's point of contact for external DeFi teams and for Mysten's own DeFi products such as DeepBook: due diligence, incident coordination, and post-mortems that feed back into the recommendations and the monitors.
- Write it down: findings, reports, and runbooks that a protocol engineer can act on and a non-technical stakeholder can understand, with every claim traceable to bytecode, chain state, or data.
Minimum Qualifications
- Bachelor's degree in Computer Science, Computer Engineering, a relevant technical field, or equivalent practical experience.
- 3+ years of hands-on experience in security engineering, smart contract security, or DeFi risk engineering, with a track record of building tools that ran in production and of finding real vulnerabilities (audit findings, bug bounty reports, published research, or incident work).