Saifuro

smart contract engineer for onchain escrow

In short

This role designs and ships the escrow smart contract system on Base for Saifuro, a web3 startup that lets AI agents trade with each other using signed, verifiable payment decisions settled onchain in USDC. It covers writing and testing the escrow contracts, owning the onchain signature verifier, scoping external audits before mainnet releases, and preparing recovery/pause mechanisms. It requires having shipped Solidity to mainnet and living in a country the company can legally hire in; Rust/Solana, ERC-4337, and security research experience are pluses.

About Saifuro
Saifuro checks payments initiated by AI agents against mandates previously approved by humans and returns signed decisions that receiving parties can verify. It provides escrow on Base and Solana for agent-to-agent trades, with onchain settlement in USDC, and does not hold customer funds. Its users are developers building agents and teams selling APIs to those agents.
Responsibilities
•Design, code, and test the escrow contract system on Base, including signed-verdict releases, independent refunds, and safeguards preventing Saifuro from moving counterparties' funds
•Own the onchain verifier that checks signatures, audience, and expiry before funds move; coordinate with the CTO, who runs the signing side and reviews the code
•Scope external audits before every mainnet release, address findings, and ship deployments with scripts, a pause switch, and a recovery runbook
•Develop milestone and multi-party escrow and deploy the contracts on additional EVM chains as future work, not a day-one requirement
Requirements
•Have shipped Solidity to mainnet
•Live in a country where the company can hire
Nice to have: EVM-level knowledge of storage layout, reentrancy, and signature verification; experience writing Rust or Anchor programs on Solana; experience with account abstraction (ERC-4337) or session keys for agents; knowledge of Circle's USDC contracts and CCTP; bug bounty or security research experience; open-source work
Conditions
•Equity: 0.30% of Saifuro, vesting
•US employees receive 100% coverage of medical, dental, and vision premiums; dependents receive 75% coverage
•Outside the US, a local plan is provided through the employer of record, or $300 a month toward private cover
•25 days of paid vacation plus public holidays; the company closes between Christmas and New Year
•14 weeks of paid parental leave for any parent
•A laptop and $1,000 toward a workspace
•$1,500 a year for learning, including conferences
•Six to eight work events a year, planned a quarter ahead and paid for by the company
•Flexible hours, with an overlap window from 14:00 to 17:00 UTC for calls and quick questions; the rest of the hours can be arranged freely; the overlap window is not the working day. The team will work something out if that window falls in the middle of the employee's night
•The role can be combined with a job at another company if the jobs do not conflict and the other work does not involve the company's contracts or compete with them
•40 hours per week

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