Xsolla - Staff Software Engineer Smart Wallet & Account Abstraction

• Account Abstraction & Smart Wallets • ERC-4337 Depth — Deep, hands-on understanding of ERC-4337: EntryPoint (v0.6 through v0.8), the UserOperation lifecycle, bundler and paymaster roles, validation rules (ERC-7562), gas estimation and its failure modes, counterfactual deployment, and signature validation for undeployed accounts (ERC-6492). • EIP-7702 & the Post-Pectra Landscape — Working knowledge of EOA delegation, its interaction with ERC-4337 EntryPoint v0.8, and the trade-offs and risks it introduces (residual key authority, delegation phishing, storage collisions). • Smart Account Implementations — Experience building on or extending production smart account implementations (Safe, Kernel, Biconomy, Coinbase Smart Wallet, or equivalent), and familiarity with modular account standards (ERC-7579 / ERC-6900). • Session Keys & Delegated Permissions — Experience designing scoped, time-limited, policy-bound authority: session keys with TTL and contract allowlists, origin binding, permission revocation, and delegated-permission standards (ERC-7710 / ERC-7715). • Production Wallet Experience — Experience designing or operating a production smart wallet or account abstraction system serving real users and real value. • Production Crypto Track Record • Scale in a Major Crypto Organization — Substantial engineering experience at a large crypto product or protocol organization — for example Coinbase, Kraken, Base, Safe, the Ethereum Foundation, Consensys / MetaMask — or a comparable wallet, exchange, or account-abstraction infrastructure team where wallet correctness and custody were core to the product. • Operational Judgment Under Value at Risk — You have shipped and operated systems where a bug meant lost funds, and you can talk concretely about the guardrails, reviews, and rollback paths you put in place. • Smart Contracts & EVM • Solidity & EVM Fluency — Ability to read, review, and write account, paymaster, and module contracts; gas-aware design; upgradeability and migration patterns; working effectively with external auditors. • L2 Specifics — Understanding of L2 execution differences and how they affect wallet design: native account abstraction on zkSync-family chains, transaction and fee models, finality and reorg behavior, and RPC and indexer semantics. • Backend Engineering • Go Engineering — Strong Go (Golang) engineering skills: idiomatic code, concurrency patterns, performance profiling. • TypeScript & SDK Design — Ability to design and own client-side SDK surfaces in TypeScript that other engineering teams — internal and external — build on top of. • Distributed Systems — Experience with distributed systems and their trade-offs (consistency, availability, failure modes), and with reconciling off-chain state against an authoritative on-chain result. • Data & Infrastructure • Kubernetes — Deploying, operating, and debugging services in a k8s environment. • Message Streaming — Kafka or NATS — event-driven patterns, consumer groups, at-least-once delivery. • Git & CI/CD — Git and modern CI/CD practices. • Key Management — Hands-on experience with key material in production: platform secure storage (Keychain / Keystore), HSMs, MPC or threshold signing, and the operational discipline around each. • Wallet Threat Modeling — Solid grasp of the wallet attack surface: signature and delegation phishing, malicious dApp origins, replay and cross-chain replay, token approval abuse, and paymaster griefing and DoS. • Cross-Team Initiative Leadership — Proven ability to lead multi-quarter technical initiatives across teams. • Architectural Influence — Track record of influencing architecture and standards beyond your immediate team. • Written & Verbal Communication — You write RFCs and design docs that people actually read. • Experience working in the video game industry, building or operating platforms for game developers, publishers, or players • Hands-on experience with the zkSync / Elastic Chain ecosystem (ZKsync OS, Matter Labs stack, native AA and paymaster flows, custom L2 operations) • Experience with embedded and ecosystem wallet providers or AA infrastructure vendors (thirdweb, Privy, Dynamic, Turnkey, Pimlico, Alchemy, Biconomy, ZeroDev, Safe{Core}) — and clear views on where to build versus buy • Experience with MPC / threshold custody, social recovery, or guardian-based recovery in a consumer product • Experience with NFT and token infrastructure at scale: ERC-721 / ERC-1155 / ERC-20 mechanics, marketplace contracts, Merkle-based airdrop and claim distribution, chain indexing services • Contributions to open-source wallet, security, or identity projects — including authorship or review of ERC / EIP standards • Familiarity with compliance requirements relevant to crypto consumer products: KYC / AML, geofencing, MiCA, SOC 2, ISO 27001, GDPR data minimization, audit logging • Experience with identity and auth integration for wallet derivation (OAuth 2.0 / OIDC, JWT verification, token scoping) • Background in platform or infrastructure engineering — building systems other engineers build on top of • Experience owning a mobile wallet surface (React Native / Expo, WebView provider injection, native signing UI) • Hands-on, up-to-date experience with modern AI tools (e.g. Claude, Copilot, Cursor) for code generation, review, and accelerating day-to-day engineering work • Xsolla operates across multiple time zones, and the smart wallet underpins identity, ownership, and value transfer for every Web3 product we ship. Strong written communication is essential — your architectural decisions and designs need to stand on their own and be actionable without you in the room. • We value directness, technical depth, and follow-through. In this domain that means saying plainly when a design has custody, security, or reversibility implications, defending your position with evidence, and staying engaged until it's resolved. Where a decision touches player funds or key material, we expect the conservative call to be argued for explicitly rather than assumed. • We may use artificial intelligence (AI) tools to support parts of the hiring process, such as reviewing applications, analyzing resumes, or assessing responses and identifying potential inconsistencies or verification signals in application materials based on available information. These tools assist our recruitment team but do not replace human judgment. Final hiring decisions are ultimately made by humans. 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