Senior Smart Contract Engineer

We are building the infrastructure powering the next generation of global crypto and stablecoin payments — connecting hundreds of millions of users across thousands of wallets and blockchain networks. Our on-chain layer is foundational to everything we do, and we take its security and correctness seriously.

About the role

As a Senior Smart Contract Engineer, you will design, write, and audit the on-chain contracts that sit at the heart of our payments network. You will work across multiple EVM-compatible chains and beyond, ensuring our protocol logic is secure, gas-efficient, and upgradeable where appropriate. This is a high-stakes, high-ownership role for engineers who hold security as a first principle and have the rigour to match.

What you'll do

• Design and implement smart contracts for payment routing, settlement, and escrow across multiple chains
• Own the full contract lifecycle — from specification and development through testing, deployment, and post-launch monitoring
• Write comprehensive test suites using frameworks such as Foundry or Hardhat, including fuzz and invariant testing
• Conduct internal security reviews and work closely with external auditors ahead of deployments
• Develop and maintain upgrade and governance mechanisms that balance flexibility with on-chain security
• Stay current with EVM developments, new opcodes, Layer 2 environments, and emerging cross-chain standards
• Collaborate with backend and protocol engineers to ensure seamless integration between on-chain and off-chain systems

What we're looking for

• 4+ years of professional smart contract development experience, with production deployments on mainnet
• Deep expertise in Solidity; familiarity with Vyper or Rust (for Solana/CosmWasm) is a bonus
• Fluency with Foundry and/or Hardhat, including advanced testing patterns (fuzzing, invariant, formal verification)
• Strong understanding of EVM internals — storage layout, gas optimisation, call patterns, and common attack vectors
• Experience with proxy patterns, upgradeability, and multi-sig governance frameworks
• Familiarity with cross-chain messaging protocols (e.g. CCIP, LayerZero, Wormhole) and Layer 2 environments
• Security-first mindset with practical experience identifying and mitigating common vulnerabilities (reentrancy, front-running, oracle manipulation, etc.)
• Strong written communication — able to produce clear specifications, post-mortems, and audit-ready documentation

Nice to have

• Experience with formal verification tools (e.g. Certora, Halmos, or Echidna)
• Background in payments, DeFi protocols, or stablecoin infrastructure
• Prior work with external audit firms or a track record of responsible disclosure
• Contributions to open-source smart contract libraries or EIPs

What we offer

• Competitive salary and equity package
• Fully remote and async-friendly working culture
• Flexible working hours and generous time off
• Home office stipend and equipment budget
• Token allocations and exposure to the cutting edge of Web3
• High-ownership role with real impact at global scale