{"id":1957433,"url":"https://alion.io/job/xsolla-middlesenior-backend-engineer-3","title":"Middle/Senior Backend Engineer","company":{"id":2375,"name":"Xsolla","domain":"xsolla.com","url":"https://alion.io/company/xsolla","size_band":"201-500","is_staffing_agency":false,"employer_type":"direct","is_intermediary":false,"listed_via":null,"ats_vendor":"Lever","truth_index":{"grade":"B","score":75,"open_postings":179,"ghost_share":0.341,"stale_share":0,"repost_share":0,"time_to_fill_p50_days":70,"computed_at":"2026-10-12T06:55:09Z"}},"role":"Backend","role_family":"Backend","seniority":"senior","employment_type":"full_time","work_mode":"remote","remote_scope":"stated_countries","remote_scope_basis":"board_field","remote_working_hours":null,"hiring_geo_confidence":"structured","locations":["Moscow, Russia","Perm, Russia","Russia"],"countries":["RU"],"hiring_countries":["RU"],"hiring_countries_total":1,"salary":null,"salary_estimate":{"min_usd":35000,"max_usd":62000,"period":"year","method":"role_seniority_country_remote_cell","sample_n":95},"experience_years_min":2,"visa_sponsorship":false,"relocation_package":false,"has_equity":false,"technologies":[{"name":"Account Abstraction","optional":false},{"name":"CI/CD","optional":false},{"name":"Docker","optional":false},{"name":"Ethereum","optional":false},{"name":"GitLab CI","optional":false},{"name":"Go","optional":false},{"name":"Graylog","optional":false},{"name":"Kubernetes","optional":false},{"name":"NATS","optional":false},{"name":"NFT","optional":false},{"name":"Polygon","optional":false},{"name":"PostgreSQL","optional":false},{"name":"RabbitMQ","optional":false},{"name":"Redis","optional":false},{"name":"Rest API","optional":false},{"name":"Smart Contracts","optional":false},{"name":"Solidity","optional":false},{"name":"Swagger","optional":false},{"name":"Token Standards","optional":false},{"name":"WebSockets","optional":false},{"name":"ZkSync Era","optional":false},{"name":"Alchemy","optional":true},{"name":"Apache Kafka","optional":true},{"name":"Biconomy","optional":true},{"name":"DeFi","optional":true},{"name":"Git","optional":true},{"name":"gRPC","optional":true},{"name":"Pimlico","optional":true},{"name":"Privy","optional":true},{"name":"Thirdweb SDK","optional":true},{"name":"ZeroDev","optional":true}],"status":"live","first_seen_at":"2026-10-02T13:38:26Z","employer_posted_date":"2026-10-02","last_verified_at":"2026-10-12T04:42:34Z","board_verified":true,"closed_at":null,"days_open":9,"trust":{"level":"ok","repost_count":0,"flags":["company_stale"],"days_open":9},"description":"ABOUT US\nXsolla is a global commerce company with robust tools and services to help developers solve the inherent challenges of the video game industry. From indie to AAA, companies partner with Xsolla to help them fund, distribute, market, and monetize their games. Grounded in the belief in the future of video games, Xsolla is resolute in the mission to bring opportunities together, and continually make new resources available to creators. Headquartered and incorporated in Los Angeles, California, Xsolla operates as the merchant of record and has helped over 1,500+ game developers to reach more players and grow their businesses around the world. With more paths to profits and ways to win, developers have all the things needed to enjoy the game.\nFor more information, visit xsolla.com.\nABOUT YOU\nWe are looking for a Middle/Senior Backend Engineer who is passionate about building scalable blockchain infrastructure and Web3 services to join our Xsolla ZK team. The best candidate will be someone who thrives in a fast-paced, highly collaborative, and exceptionally dynamic setting and is excited to develop backend systems that power NFT marketplaces, smart wallets, and blockchain-based gaming infrastructure.\nStrong backend development skills in Go are essential, along with experience in building high-load distributed systems and working with databases. The ability to design resilient microservices architecture and integrate with blockchain networks will be key to your success in this role.\nIf you're passionate about building the infrastructure layer for next-generation gaming and love working on cutting-edge blockchain technology that enables gamers to truly own their digital assets, we would love to hear from you!\nAbout the project\nXsolla ZK is building a cross-game infrastructure that empowers gamers to freely trade and use their digital assets without barriers. The backend team develops services for:\nXsolla Bazaar - NFT marketplace for trading digital assets across Ethereum, Polygon, and Xsolla ZK chains\n\nWeb3 Backpack - Smart wallet backend with account abstraction (ZK SSO 4337)\n\nBlockchain Services - Event scanners, transaction processors, and Web3 connectors\n\nBFF Layer - Backend-for-Frontend services orchestrating complex Web3 operations\n\nTech Stack:\nLanguage: Go (go-ethereum, ethkit, idiomatic concurrency patterns)\n\nDatabases: MongoDB, PostgreSQL, Redis\n\nMessage Queue: NATS, RabbitMQ, Kafka\n\nAPI: REST, WebSocket, gRPC, OpenAPI (Swagger)\n\nBlockchain Infrastructure:\n\nZK Stack / ZKsync Era: EraVM, zksolc/zkvyper compilers, system contracts, bootloader, native Account Abstraction on zkSync-family chains\n\nAccount Abstraction (ERC-4337): EntryPoint (v0.6-v0.8), UserOperation lifecycle (prepare→sign→submit→confirm), bundler and paymaster roles, ERC-7562 validation rules, ERC-6492 signature validation for undeployed accounts\n\nEthereum L1: go-ethereum, abigen for smart contract bindings, RPC and indexer semantics\n\nSmart Contracts: Solidity, ERC-20/721/1155, modular account standards (ERC-7579 / ERC-6900), session keys (ERC-7710 / ERC-7715)\n\nSignature Schemes: EIP-712 typed data, ERC-1271 contract signatures, WebAuthn/passkey (P-256)\n\nInfrastructure: Docker, Kubernetes, GitLab CI/CD, Graylog\n\nKey Technical Challenges:\nZK Stack Integration: Working with EraVM execution environment, native Account Abstraction on zkSync-family chains, double resource accounting (EE gas + native computational resources), L1↔L2 communication via ZKsync Gateway, finality and reorg behavior\n\nAccount Abstraction Backend Services: Implementing the ERC-4337 UserOperation lifecycle, integrating with bundlers and paymasters, handling gas estimation failure modes and counterfactual deployment\n\nSmart Contract Interaction: Generating Go bindings via abigen, handling factory dependencies for contract deployment, implementing EIP-712 transaction signing and ERC-1271 signature verification\n\nSession Keys & Delegated Permissions: Supporting scoped, time-limited, contract-allowlisted authority (ERC-7710 / ERC-7715) for gasless, prompt-free gameplay transactions\n\nEvent Processing: Building blockchain event scanners for multiple chains (Ethereum, Polygon, Xsolla ZK), implementing reorg handling and transaction finality tracking\n\nHigh-Availability Architecture: Designing resilient microservices for NFT marketplace and wallet backends with real-time WebSocket updates\n\nResponsibilities\nDevelop backend services using Go with ethkit and go-ethereum for Ethereum interactions and RPC integration\n\nIntegrate with ZK Stack infrastructure: work with EraVM, system contracts, and L1↔L2 messaging\n\nBuild and maintain wallet backend indexing integrations for real-time token balance tracking and webhooks (via internal indexer or third-party providers)\n\nDesign and implement APIs for NFT marketplace and orderbook services, including on-chain order matching and settlement flows\n\nImplement smart contract interaction layer using abigen-generated Go bindings for ERC-20/721/1155 tokens\n\nBuild Account Abstraction (ERC-4337) backend support: UserOperation submission and monitoring, paymaster gas-sponsorship logic, session-key issuance and revocation\n\nDevelop blockchain event scanners with reorg handling for Ethereum, Polygon, and Xsolla ZK chains\n\nImplement BFF (Backend-for-Frontend) services orchestrating complex multi-chain operations\n\nDesign efficient caching and indexing strategies for on-chain data using Redis and MongoDB\n\nWrite comprehensive tests including integration tests with local ZKsync test environment\n\nDocument APIs using OpenAPI/Swagger specification\n\nMonitor and troubleshoot production systems, handle blockchain-specific edge cases (stuck transactions, gas estimation)\n\nNice to Have\nRequired:\n2+ years of commercial experience with Go\n\nStrong understanding of MongoDB and PostgreSQL (query optimization, indexing)\n\nExperience with Redis for caching and session management\n\nKnowledge of message queues (NATS, RabbitMQ, or similar)\n\nExperience designing and implementing REST APIs with OpenAPI/Swagger\n\nUnderstanding of microservices architecture patterns\n\nExperience with Docker and container orchestration basics\n\nProficiency with Git and GitLab CI/CD\n\nSolid understanding of distributed systems concepts\n\nPreferred:\nExperience with Ethereum/EVM blockchain integration:\n\nWorking with go-ethereum library and RPC nodes\n\nSmart contract interaction via ABI bindings (abigen)\n\nUnderstanding of transaction lifecycle, gas estimation, nonce management\n\nKnowledge of ZK Stack / ZKsync Era:\n\nEraVM execution model and differences from EVM, including native Account Abstraction on zkSync-family chains\n\nSystem contracts (ContractDeployer, NonceHolder, etc.)\n\nL1↔L2 communication, bridging, and finality/reorg behavior\n\nWorking knowledge of ERC-4337 Account Abstraction:\n\nEntryPoint contract and the UserOperation lifecycle\n\nBundler and paymaster roles, gas estimation failure modes\n\nSession keys and delegated permissions (ERC-7710 / ERC-7715)\n\nFamiliarity with signature schemes: EIP-712 typed data, ERC-1271 contract signatures, WebAuthn/passkey signers\n\nExposure to AA infrastructure providers (any of: Sequence, thirdweb, Privy, Dynamic, Turnkey, Pimlico, Alchemy, Biconomy, ZeroDev, Safe{Core}) for wallet, indexer, or transaction-relay integrations\n\nKnowledge of token standards (ERC-20, ERC-721, ERC-1155) and their implementation details\n\nExperience with blockchain event processing: event scanning, reorg handling, finality\n\nUnderstanding of DeFi concepts and NFT marketplace mechanics\n\nExperience with Kubernetes for container 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