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xsolla - Senior QA Engineer Position for Xsolla's Smart Wallet in Web3

Europe2d ago

Requirements

• Bachelor's degree in Computer Science, Software Engineering, Information Systems or a related field (or international equivalent). • 6+ years in software testing or quality engineering, including 2+ years of hands-on testing on EVM-based products. • Web3 libraries and tooling • Hands-on work with viem and wagmi (ethers.js also counts): reading contract state, sending transactions, and decoding events and revert errors from test code. • Deploying and interacting with smart contracts from the command line with Foundry (forge, cast, anvil) or Hardhat; able to read Solidity well enough to know what a contract is meant to do. • Chain forking and simulation with Anvil, Tenderly or similar tools, and tracing a failed transaction from a block explorer or transaction trace down to its revert reason. • On-chain fundamentals • A working model of Ethereum transactions: nonces, gas, receipts, events and logs, reverts, reorgs and finality — including the gap between a sequencer confirmation and L1 finality on a rollup — and how indexers can lag or diverge from chain state. • Token standards: ERC-20, ERC-721 and ERC-1155 mechanics, including approvals and the safe-transfer callbacks a contract wallet must implement to receive NFTs. • How wallet signers work: EOAs, embedded wallets and smart accounts; personal_sign (EIP-191) and typed data (EIP-712); the EIP-1193 provider; signature validation for contract accounts (ERC-1271). • Practical understanding of account abstraction (ERC-4337): UserOperations, bundlers, the EntryPoint, paymasters, counterfactual deployment and CREATE2 address derivation, and session keys. • Wallet security basics: signature replay and cross-chain replay, phishing via typed-data signing, and token approval abuse — and how to design test cases that catch them. • Testing and automation • Test automation in TypeScript or JavaScript, and UI automation with Playwright or a similar framework. • API testing over REST and JSON-RPC, including bundler methods (eth_sendUserOperation, eth_estimateUserOperationGas, eth_getUserOperationReceipt), and basic SQL. • Daily hands-on use of AI coding tools (Claude Code, Codex, Cursor) for test design, automation and review — generating test cases from specs, analysing logs and transaction traces — including configuring them for a repository. • Ways of working • Able to run complex, high-impact testing with minimal supervision and wide latitude for independent judgment. • Excellent written and spoken English, and proven collaboration in cross-functional teams across time zones. • Experience on a wallet, decentralized exchange or NFT marketplace. • ZK Stack and zk-rollups: native account abstraction and paymaster flows on zkSync-family chains, and how finality, gas and EVM compatibility differ from Ethereum mainnet. • Embedded, MPC or white-label wallet SDK integrations. • EIP-7702 delegation, and ERC-6492 signature validation for accounts that are not yet deployed. • Writing on-chain tests in Foundry, including fuzz and invariant tests; familiarity with OpenZeppelin contracts and the ERC-4337 reference implementation. • Consumer-scale or gaming products. • Load and performance testing of high-volume transaction flows, for example with k6.

Responsibilities

• A consumer smart wallet built on account abstraction, so players can own and use digital items without managing keys or gas themselves. • Integrations with an external wallet-infrastructure partner and with Xsolla's existing player products. • Taking the wallet from testnet to a production launch on an Ethereum-compatible Layer 2. • Own the end-to-end test strategy for the wallet: sign-in, wallet creation, asset display, send and receive, and transaction confirmation on Xsolla ZK. • Test account-abstraction flows: UserOperation construction and validation, bundler submission, EntryPoint execution, paymaster-sponsored gas, and session-key and signer behaviour. • Test signing end to end: personal_sign and EIP-712 typed-data requests through the EIP-1193 provider, and signature validation by the wallet contract (ERC-1271), including before the wallet is deployed. • Verify counterfactual deployment: that the address derived with CREATE2 from the factory, salt and init code matches the deployed wallet contract, on a forked or local chain, before it reaches mainnet. • Deploy, call and inspect smart contracts from the command line to set up test state and reproduce defects. • Use chain-forking and simulation tools to test against real network state without real funds, and trace failed transactions to their root cause. • Validate the full transaction lifecycle — broadcast, inclusion, reorgs and finality — and its failure paths: reverts, failed UserOperations, insufficient balance, expired session keys, ownership changing mid-flight, and bundler errors. • Reconcile what players see with on-chain state: indexer balances and NFT ownership against contract state, including when the indexer lags or diverges, and the account-to-wallet records behind Xsolla ID. • Test transfers and approvals across ERC-20, ERC-721 and ERC-1155, including partial ERC-1155 quantities and safe transfers into contract wallets. • Write acceptance tests for a partner's wallet SDK and contracts, and report integration defects with the evidence needed to route them to the right owner. • Build and maintain automation: Playwright for wallet UI flows, and scripted on-chain checks in TypeScript that run in CI. • Set up and maintain AI tooling in the test repositories (Claude Code, Codex, Cursor: rules, context, harness) so QA and engineers use it effectively. • Plan and run testnet-to-mainnet release validation, including contract deployment verification and post-deploy smoke checks. • Work with security on signing, key handling and key-export flows, and test for signature replay, typed-data phishing and token approval abuse. • Mentor QA engineers who are new to Web3, and raise on-chain testing practice across teams.

Benefits

• We are passionate about fostering a supportive environment for our team, so we prioritize the physical, mental, and emotional well-being of our employees and their families through a comprehensive Benefits Program. This includes medical, dental, and vision, PTO, and a personalized career roadmap for each employee. By investing in professional development through training and educational opportunities, we ensure that our team thrives both personally and professionally. Together, we're not just building a business; we're cultivating a community that values creativity, collaboration, and the transformative power of play.