Smart Contract Engineer (Solidity, EVM) — Saifuro

The Bitcoin Street Journal; United States; Remote; USD 170,000 - 220,000; Full time

Benefits offered by this job

Health premiums cover (US)

Equity 0.30% vesting

Paid vacation 25 days + holidays

14 weeks parental leave

Laptop provided + $1,000 workspace

Learning budget $1,500/year

Job summary

Saifuro is seeking a Solidity developer to own and evolve the on-chain escrow and verifier systems. You will build and test contracts on the Base network, ensuring secure signature verification and robust on-chain logic. You will coordinate external audits before mainnet releases, implement findings, and prepare deployment scripts with recovery runbooks.

The role offers flexible hours and remote work, with a focus on security, audits, and cross-chain expansion in the coming years.

Qualifications

• Shipped Solidity to mainnet.
• Experience with on-chain verification and signature checks.
• Familiarity with security research and audits for smart contracts.

Responsibilities

• Own the escrow contract system on Base; design, code and tests.
• Own the on-chain verifier path; ensure correct signature verification and expiry checks.
• Coordinate external audits prior to mainnet releases; respond to findings and implement fixes.

Skills

Solidity

Mainnet deployment

On-chain verification

Security research

Rust

Solana

ERC-4337

Job description

• Company: Saifuro


• Location: Remote


• Sector: Blockchain


• Source: web3.career

Saifuro checks payments that AI agents try to make. An agent asks to spend, we compare the request with a mandate a human approved earlier, and the answer comes back signed so the receiving side can verify it. There’s escrow on Base and Solana for trades between agents, and settlement is in USDC, onchain. We never hold customer funds. The docs are public at docs.saifuro.com, and the people who use them are developers building agents and the teams selling APIs to those agents.

The escrow is the one place where our code holds other people’s money. Funds go in, sit until a signed verdict says the deal is done, and come out to the seller or back to the buyer, with no path in which Saifuro can move them. Your job is to own the EVM side: the escrow, the verifier that checks our signatures onchain, the audits and the deployments. Call it Solidity developer, smart contract developer or blockchain developer if you prefer. It’s Solidity first.

What you’d be doing

• The escrow. One contract system on Base: funds held until a signed verdict releases them, refunds that work without us, and no path in which Saifuro can move a counterparty’s money. Design, code and tests are yours.


• The verifier. The contracts check our signature, the audience and the expiry before anything moves. You own that path onchain. The CTO runs the signing side and reviews your code.


• Audits and releases. An external audit before every mainnet release. You scope it, answer the findings and ship, with deployment scripts, a pause switch and a recovery runbook alongside.


• What comes next, at your pace. Milestone and multi-party escrow next year, and the same contracts on more EVM chains. None of it is a day-one requirement.

What we need from you

• You’ve shipped Solidity to mainnet.


• You live in one of the countries we can hire in.

Beyond these requirements, we’ll support you in learning whatever else the role demands. If your experience is relevant but your title differs, we would still like to hear from you. Work outside a job counts too: open source, hackathons and your own projects.

It helps, but isn’t required, if you know storage layout, reentrancy and signature verification at the EVM level, if you’ve written Rust or Anchor programs on Solana, if you’ve worked with account abstraction (ERC-4337) or session keys for agents, if you know Circle’s USDC contracts and CCTP, if you’ve found bugs for a bounty or done security research, or if your work is open source.

Pay and benefits

• Salary $170,000 to $220,000. That’s the US range. Outside the US we pay in USD, or in USDC if you’d rather, and set the offer against the top of the local market.


• Equity: 0.30% of Saifuro, vesting.


• Health: 100% of medical, dental and vision premiums for US employees, 75% for dependents. Outside the US, the local plan through our employer of record, or $300 a month toward private cover.


• 25 days of paid vacation plus your public holidays, and we close between Christmas and New Year.


• 14 weeks of paid parental leave, for any parent.


• A laptop and $1,000 toward your workspace.


• $1,500 a year for learning, conferences included. That’s on top of the events you’ll attend for work: six to eight a year, planned a quarter ahead, on the company.

Hours are flexible. The one thing we ask is to be online from 14:00 to 17:00 UTC, when the team overlaps for calls and quick questions. That’s a window, not the working day. The rest of your hours are yours to arrange. A mainnet incident doesn’t keep office hours. If that window is the middle of your night, say so and we’ll work something out.

You can combine this with a job at another company, as long as the two don’t conflict and nothing you’d write there touches our contracts or competes with them.