Protocol Engineer

At Fun, we’re building the financial infrastructure for internet capital markets.

The systems that power global finance were designed for a different era: slower, fragmented, and constrained by borders. Today, value is digital, global, and moves instantly, but the experience of moving it hasn’t caught up.

Fun offers the highest converting payment solution in the digital asset space – a unified system that enables users to complete any on-chain action using crypto, exchange balances, or fiat from a card or bank account, all in a single, seamless flow.

Our goal is simple: make transacting with any asset feel effortless, anywhere in the world.

Role Overview

We're looking for a Protocol Engineer to join our core blockchain team and help build the foundation of Web3 payments infrastructure. This high-impact role offers the opportunity to work on challenging technical problems at the intersection of smart contracts, cross-chain protocols, and decentralized finance.

You will design and implement secure, efficient smart contract systems and blockchain integrations that power millions of transactions across multiple chains. This role is perfect for a technically strong engineer who thrives in fast-paced environments and wants to shape the future of decentralized finance.

Responsibilities

• Design, develop, and deploy secure smart contracts and protocol implementations across multiple blockchain platforms
• Collaborate with backend and product teams to architect blockchain solutions that meet business requirements

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• Write highly efficient, well-tested code and participate in security audits to ensure protocol safety
• Research and evaluate new blockchain technologies, protocols, and DeFi primitives for integration opportunities
• Contribute to incident response and debugging on-chain issues to ensure protocol reliability
  
  

Requirements

• Strong experience building and deploying production smart contracts on major blockchain platforms
• Deep understanding of blockchain architecture, consensus mechanisms, and cryptographic principles
• Hands-on experience with smart contract development languages (Solidity, Rust, Move, etc.)
• Solid grasp of DeFi protocols, token standards, and cross-chain communication patterns
• Strong security mindset with knowledge of common smart contract vulnerabilities and best practices

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• Clear communicator who can explain complex blockchain concepts to cross-functional teams
  
  

Nice To Have

• Production experience with multiple blockchain ecosystems (Ethereum, Solana, L2s, etc.)
• Previously worked at crypto startup or Web3 infrastructure company
• Experience with cross-chain bridges, oracles, or interoperability protocols
• Background with high-volume DeFi protocols or DEX infrastructure
• Contributions to blockchain open source projects or protocol research
• Experience with formal verification or advanced smart contract testing frameworks