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    Security Engineer

    ParityFull TimeNA

    Remote Posted: Dec 13, 2025
    Job description
    Parity builds and maintains core open-source blockchain infrastructure, including Polkadot, the Polkadot SDK, and Kusama. The Security Engineer will join the Security Engineering team and focus on strengthening the security posture of Parity’s blockchain ecosystem. This role involves auditing and, where required, writing secure Rust code, performing in-depth manual and...
  • Job Expired
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    Smart Contract Engineer

    PolymarketFull TimeNA

    Remote Posted: Dec 13, 2025
    Job description
    Polymarket operates a large-scale prediction market protocol where users trade on real-world outcomes using on-chain infrastructure. The Smart Contract Engineer will join the core protocol team and own the design, development, and deployment of Solidity smart contracts that secure and operate high-volume peer-to-peer markets. This role focuses on building and...
  • Job Expired
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    Rust Engineer

    CryptioFull TimeNA

    Remote Posted: Dec 13, 2025
    Job description
    Cryptio builds enterprise-grade back-office and data infrastructure used for accounting, reporting, and operational workflows in the digital asset ecosystem. The Rust Engineer will join the Accounting squad, focusing on the systems that power cost basis calculations, PnL, staking, derivatives, accruals, and large-scale reporting pipelines. This role owns the design and...
  • Difficulty - Medium
    Total Plays - 11
    Allowed Time - 10 sec
    Best time - 3.307

    Why should developers avoid using tx.origin for authentication?

    Tip: Click "Play" to reveal options and start playing.

    #A
    #B
    #C
    #D
    Explanation:
    Attackers can trick users into calling a malicious contract. That contract then makes a call where tx.origin equals the victim’s address. This bypasses access control and leads to unauthorized actions.
  • Difficulty - Medium
    Total Plays - 12
    Allowed Time - 10 sec
    Best time - 1.493

    Why are fallback functions dangerous?

    Tip: Click "Play" to reveal options and start playing.

    #A
    #B
    #C
    #D
    Explanation:
    Fallback functions run automatically when unknown calls or plain ETH are sent. If they contain external calls or heavy logic, attackers can trigger recursion or re-entrancy. They must be kept minimal and safe.
  • Difficulty - Medium
    Total Plays - 11
    Allowed Time - 10 sec
    Best time - 1.974

    Why can abi.encodePacked cause issues?

    Tip: Click "Play" to reveal options and start playing.

    #A
    #B
    #C
    #D
    Explanation:
    encodePacked removes padding, which can produce identical byte sequences for different inputs. When combined with hashing, this may cause collisions. Using abi.encode is safer for multi-field data.
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    Senior Backend & Smart Contract Engineer (Rust/Solana)

    Breeze (Anagram)Full TimeNA

    Remote Posted: Dec 10, 2025
    Job description
    Breeze is developing infrastructure that enables users to earn yield on digital assets through a non-custodial platform directly embedded into existing applications. This role centers on designing Rust-based Solana programs and maintaining backend components such as indexers, risk engines, and analytics systems. The engineer will work closely with product and...
  • Job Expired
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    Rust Backend Engineer

    SvixFull TimeNA

    Remote (US/EU) or San Francisco (Hybrid / On-Site) Posted: Dec 10, 2025
    Job description
    Svix is hiring a Rust-focused Backend Engineer to help build and scale its server-to-server communication platform. The company develops high-performance message delivery infrastructure used by customers ranging from fast-growing startups to large enterprises. This role involves implementing backend services in Rust, designing systems that support high availability, and contributing to...
  • Job Expired
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    Rust-Simplicity Maintainer

    BlockstreamFull TimeNA

    Remote Posted: Dec 10, 2025
    Job description
    Blockstream is seeking a Rust-Simplicity Maintainer to oversee its Rust-based implementation of the Simplicity language and related libraries. The role centers on maintaining multiple interconnected crates—such as rust-simplicity, SimplicityHL, hal-simplicity, rust-elements, and elements-miniscript—ensuring they function cohesively within the broader Simplicity ecosystem. This position involves architecture, implementation, testing, and long-term maintenance...
  • Job Expired
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    Smart Contract Engineer

    VedaFull TimeNA

    Remote Posted: Dec 9, 2025
    Job description
    This role supports Veda’s Solidity engineering organization, contributing to the architecture, reliability, and security of smart contracts that power high-TVL DeFi vaults. The position involves designing new protocol features, maintaining existing vault infrastructure, and ensuring strong security practices through threat modeling, formal verification, and audit-by-design methodologies. Engineers will work across...