Decentralized Applications Engineer

Company Description

Xpay.Sh is revolutionizing Agent to Agent payments in the Agentic Economy with its cutting-edge control plane for managing x402 payments. The platform enables businesses to prevent runaway agent costs, monetize APIs instantly, and gain complete transaction visibility. By tackling modern challenges in payment systems, Xpay.Sh is empowering organizations to optimize operations and achieve transparency. Based at the intersection of technology and finance, Xpay.Sh is redefining what's possible in payment solutions.

About XPay.Sh

XPay.Sh is building plug-and-play Agentic Payments—secure, modular, and ultra-fast money movement for AI agents and apps—powered by our X402 Protocol. We sit at the intersection of Web3, DeFi, and real-world payments, enabling compliant, programmable, and cross-rail settlement for human-to-AI and AI-to-AI transactions.

As a Founding Engineer, you’ll shape the core protocol, architecture, and engineering culture from day one—and ship mission-critical primitives that power autonomous payments at scale.

Role Summary

You’ll lead the hands-on build of our Web3 stack : smart contracts, DeFi primitives, off-chain services, chain integrations / L2s, and developer SDKs. You’ll partner with product to turn customer needs into shippable specs, own security and reliability, and help hire the early engineering team.

What You’ll Do

• Design & ship smart contracts (Solidity / Rust) for payment orchestration : vaults, escrows, streaming, staking, fee routing, and settlement logic across EVM / L2s.
• Build reliable backends & SDKs that bridge on-chain logic with off-chain services (indexers, event pipelines, signing services, risk / compliance hooks).
• Own security : test suites, invariants, upgradeability patterns, audit readiness, incident runbooks, and bug-bounty posture.
• Optimize performance & cost : chain / L2 selection, gas efficiency, batching, meta-tx / AA, and cross-chain messaging where needed.
• Integrate with DeFi & payment rails : stablecoins, fiat on / off-ramps, custody / RPC providers, oracles, bridges.
• Define engineering standards : CI / CD, observability, code review, release cadence;

mentor early hires and contractors.

Must-Have Qualifications

shipped smart contractson mainnet / testnet (Solidity and / or Rust).

bias to ship.

Nice-to-Have

Key Deliverables (First 30 / 60 / 90 Days)

30 Days

60 Days

prep for external audit.

90 Days

implement monitoring / alerts, replay backfills, and incident runbooks.

document refunds / disputes & compliance hooks.

host first internal / external dev preview.

establish code review &release cadence.

How We Work

Compensation