Protocol Engineer — Swiss Nexus

Swiss Nexus is recruiting on behalf of a technology company building payment infrastructure for digital assets.

The company is developing products that make onchain transactions more intuitive, secure and accessible for users, developers and businesses. Its infrastructure enables users to complete blockchain-based payments and other onchain actions using assets held across self-custodial wallets, centralized exchanges and fiat on-ramps.

The team is now hiring a Protocol Engineer to help develop the foundations of its Web3 payments infrastructure.

The Role

This is a high-impact engineering position at the intersection of smart contracts, cross-chain protocols, DeFi and payment settlement.

You will design and implement secure onchain systems capable of supporting payment activity across multiple blockchain networks. You will work closely with backend engineers and product stakeholders to translate commercial requirements into reliable protocol architecture.

The position is particularly suited to a crypto-native engineer who is comfortable owning protocol design, implementation, testing and production reliability.

What You'll Do

• Design, develop and deploy secure smart contracts and protocol components across multiple blockchain platforms.
• Architect onchain payment and settlement infrastructure in collaboration with backend and product teams.
• Translate product and business requirements into robust protocol designs.
• Write efficient, well-tested smart contract code.
• Participate in internal and external security reviews.
• Research and assess new blockchain networks, DeFi primitives and interoperability protocols.
• Support incident response, debugging and remediation of onchain issues.
• Contribute to technical decisions affecting protocol security, scalability and reliability.

What We're Looking For

• Proven experience building and deploying production smart contracts on major blockchain platforms, including Ethereum and L2 networks.
• Strong hands-on expertise with Solidity.
• Experience with Rust or Move is advantageous.
• A solid understanding of DeFi protocols, token standards and cross-chain communication patterns.
• A strong security mindset, including knowledge of common smart contract vulnerabilities and defensive engineering practices.
• The ability to collaborate effectively with backend engineers and product stakeholders.
• Confidence owning protocol work from initial design through production deployment and ongoing support.

Nice to Have

• A deep understanding of blockchain architecture, consensus mechanisms and applied cryptography.
• Production experience across multiple L1 and L2 ecosystems, including non-EVM networks.
• Familiarity with bridges, oracles and interoperability frameworks.
• Experience with formal verification or advanced contract-testing tools such as Foundry or Echidna.
• Contributions to open-source blockchain projects or protocol research.
• Previous experience building blockchain-based payment or settlement infrastructure.

About Swiss Nexus

Swiss Nexus is a specialist recruitment firm connecting engineering, product and leadership talent with companies operating across blockchain, Web3 and fintech