Company Description Xpay.sh is revolutionizing 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-playAgentic Payments —secure, modular, and ultra-fast money movement for AI agents and apps—powered by ourX402 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 aFounding 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 DoDesign & ship smart contracts(Solidity/Rust) for payment orchestration: vaults, escrows, streaming, staking, fee routing, and settlement logic across EVM/L2s. Build reliable backends & SDKsthat 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. Collaborate across functionsto translate customer workflows (agent-initiated payments, compliance gates, refunds/disputes) into production features.Must-Have Qualifications3+ years buildingproduction Web3systems; shippedsmart contractson mainnet/testnet (Solidity and/or Rust). Strong grasp ofDeFi primitives(AMMs, lending, escrows/streams, staking/locking, tokenomics) and protocol trade-offs. Solidbackend engineering(Node/Go/Rust/Python), API design (REST/gRPC), eventing, and data stores. Experience runningblockchain infra : nodes/RPCs, indexers, subscription/event pipelines, key management. Security mindset : audits, fuzzing/static analysis, threat modeling, upgrade patterns. High ownership in ambiguous, 0→1 environments; bias to ship.Nice-to-HaveAccount Abstraction / ERC-4337, meta-transactions, session keys for agentic flows. Formal verification, Slither/Foundry/Hardhat mastery, OpenZeppelin wizardry. Frontend chops (React/TypeScript) to deliver full-stack slices early on. Token design/governance (DAO frameworks), compliance familiarity (KYT, travel rule, sanctions screening) and regulated partners. Prior startup/founding experience. Key Deliverables (First 30/60/90 Days)30 Days Stand up core repo structure, CI/CD, Foundry/Hardhat toolchain, linting, coverage, and pre-commit hooks. Draft v1architecture RFCfor X402 on-chain/off-chain boundaries, custody/RPC choices, and indexer strategy. Skeletonpayments escrow/streaming contractwith tests + reference TypeScript SDK. 60 Days ShipMVP smart-contract suite(escrow, fee splitter, payout router) to testnet with full e2e tests and event indexer. Harden security posture: fuzzing, invariants, gas reports, upgrade plan; prep for external audit. Basicagent-triggered payment flow(session keys/AA or relayer) integrated with a demo app. 90 Days Launchv1 on mainnet/L2with canary customers; implement monitoring/alerts, replay backfills, and incident runbooks. Integrate at least onestablecoin + on/off-ramp ; document refunds/disputes & compliance hooks. Publishdeveloper docs & SDK ; host first internal/external dev preview. Close & onboard thefirst engineering hire/contractors ; establish code review & release cadence. How We WorkPrinciples:security first, ship small/fast, automate everything, docs or it didn’t happen. Stack:Solidity/Foundry/Hardhat, TypeScript/Node, Postgres/ClickHouse, Docker, Grafana/Prometheus, EVM L2s (Arbitrum/OP/Base), AA/4337 where practical. CompensationCompetitive salary +meaningful equity(founding band).
Job Title
Developer Relations Manager