About this role
About the project
Xsolla ZK is building a cross-game infrastructure that empowers gamers to freely trade and use their digital assets without barriers. As a Fullstack Engineer, you'll work across the entire stack:
Products:
- Xsolla Bazaar — NFT marketplace for trading digital assets
- Web3 Backpack — Smart wallet with account abstraction
- Web3 SDKs — Developer toolkits for blockchain integration
- Admin Panels — Internal tools for managing Web3 operations
Tech Stack:
Backend:
- Language: Go (go-ethereum, ethkit)
- Databases: MongoDB, PostgreSQL, Redis
- API: REST, WebSocket, gRPC, OpenAPI (Swagger)
- Message Queue: NATS, RabbitMQ, Kafka
- Blockchain Infrastructure:
- ZK Stack / ZKsync Era (EraVM, system contracts, native Account Abstraction)
- Account Abstraction (ERC-4337): EntryPoint, UserOperation lifecycle, bundlers, paymasters
- Ethereum L1 integration, abigen contract bindings
Frontend:
- Languages: JavaScript (ES6+), TypeScript
- Frameworks: React, Next.js, React Native
- State Management: RTK, Zustand
- Styling: Tailwind CSS, Tamagui, CSS-in-JS
- Web3 Libraries & Standards:
- Wallet provider standards: EIP-1193, EIP-6963 (multi-wallet discovery), EIP-5792 (batched calls)
- ethers.js, viem for Ethereum interactions
- wagmi for React hooks
- WalletConnect for multi-wallet support
- Embedded/AA wallet SDK (e.g. Sequence, thirdweb, Privy, Dynamic, or equivalent) for social-login smart accounts
Infrastructure:
- DevOps: Docker, Kubernetes, GitLab CI/CD
- Monitoring: Graylog, Prometheus
Key Technical Challenges:
- Full-Stack Web3 Features: Building end-to-end flows from smart contract events to real-time UI updates
- Account Abstraction Integration: Implementing embedded/smart-account wallets with social auth, ERC-4337 UserOperation flows, and gasless transactions via paymasters
- ZK Stack Backend: Working with EraVM differences, native Account Abstraction on zkSync-family chains, handling L1↔L2 bridging operations
- Signature & Session Handling: Implementing EIP-712 signing, ERC-1271 verification, and session-key-scoped permissions for in-game transactions
- Cross-Platform Consistency: Sharing business logic between web and mobile using React/React Native
Responsibilities
Backend Development:
- Develop backend services in Go using go-ethereum / ethkit for wallet operations and blockchain interactions
- Implement and monitor the ERC-4337 UserOperation lifecycle (prepare→sign→submit→confirm) against bundlers and paymasters
- Implement smart contract interaction layer with abigen -generated Go bindings
- Build Account Abstraction support: paymaster gas-sponsorship logic, session-key issuance (ERC-7710 / ERC-7715) for gameplay transactions
- Design BFF services orchestrating data from multiple blockchain sources, indexers, and wallet infrastructure providers
Frontend Development:
- Build responsive applications using React/Next.js integrated with an embedded/AA wallet SDK
- Implement Embedded Wallet flows: social auth (Google, Apple), email login, passkey (WebAuthn/P-256) support
- Create Web3-enabled UIs using wagmi hooks and viem for contract reads/writes, following EIP-1193/EIP-6963 provider standards
- Implement transaction confirmation flows that clearly convey what the player is approving (EIP-712 typed-data signing)
- Develop real-time features with WebSocket subscriptions for blockchain events
- Build cross-platform components with Tamagui for web and React Native
Full-Stack Integration:
- Design and implement complete features from smart contract events to UI updates
- Handle ZK Stack specifics : EraVM gas model differences, native Account Abstraction, L1↔L2 bridging UI flows
- Implement transaction tracking : status polling, reorg handling, user notifications
- Create admin panels for managing NFT drops, marketplace settings, and analytics
- Write comprehensive tests for both backend (Go) and frontend (Jest, React Testing Library)
- Document APIs using OpenAPI/Swagger and maintain technical documentation
Nice to Have
Required:
Backend Skills:
- 3+ years of commercial experience with Go
- Strong knowledge of REST API design and implementation
- Experience with MongoDB and/or PostgreSQL
- Understanding of microservices architecture
Frontend Skills:
- 3+ years of experience with React and modern JavaScript/TypeScript
- Proficiency in state management solutions (Redux, Zustand, etc.)
- Experience with responsive design and CSS frameworks
- Understanding of web performance optimization
General:
- Experience with Git and CI/CD pipelines
- Familiarity with Docker and containerization
- Strong problem-solving and communication skills
Preferred:
Web3 & Blockchain:
- Working knowledge of ERC-4337 Account Abstraction : EntryPoint, UserOperation lifecycle, bundler/paymaster roles
- Understanding of session keys and delegated permissions (ERC-7710 / ERC-7715) and signature schemes (EIP-712, ERC-1271, WebAuthn/passkey)
- Familiarity with wallet provider standards : EIP-1193, EIP-6963, EIP-5792
- Exposure to an embedded/AA wallet SDK (Sequence, thirdweb, Privy, Dynamic, Turnkey, or equivalent):
- Embedded Wallet integration (social auth, passkeys)
- Indexer/data-availability integration for balance/activity tracking
- Gas-sponsorship / transaction-relay APIs
- Knowledge of ZK Stack / ZKsync Era :
- Understanding of EraVM vs EVM differences
- L1↔L2 communication patterns
- Native Account Abstraction on zkSync-family chains
- Experience with ethers.js , viem , and wagmi for React
- Understanding of smart contract interaction : ABI, events, transaction lifecycle
- Knowledge of token standards (ERC-20, ERC-721, ERC-1155)
Additional:
- Experience with Next.js SSR/SSG and App Router
- Familiarity with React Native and Tamagui for cross-platform
- Understanding of WebSocket for real-time blockchain events
- Knowledge of Kubernetes and cloud infrastructure