Описание

We are hiring a Software Engineer, Web3 for Xsolla ZK, Xsolla's Web3 ecosystem on a zkSync-based L2. This is a senior fullstack role: you work across backend, frontend and smart contracts.

Responsibilities

Own features end to end: backend, frontend and production
Own the on-chain / off-chain architecture of your product: what lives in contracts, what lives in services, and how the two stay consistent
Make and justify architecture decisions in writing
Own security and correctness of what you ship: signing flows, interactions with contracts that hold user assets, keys and secrets
Own production operation of your services, as part of the team's on-call rotation
Build backend services in Go and TypeScript: chain indexing, transaction relaying, event processing, APIs for dApps and SDKs
Build infrastructure backend services for tokenizing in-game items and currencies
Build dApp frontends in React: wallet connection, transaction signing, on-chain state in the UI
Integrate smart wallets into products: accounts, paymasters, bundlers
Develop SDKs used by game studios and partners
Monitor services and contracts in production and take part in on-call
Review code
Set up and maintain AI tooling in the repositories (Claude Code, Codex, Cursor: rules, context, harness) so the team uses it effectively

Requirements

5+ years of commercial software development, with senior-level production experience across backend and frontend dApps that you shipped to production and maintained
Experience with Web3 libraries and wallets
Experience with viem and wagmi in production: clients and transports, contract reads and writes with typed ABIs, event subscriptions, wagmi hooks and connectors, caching and invalidation of on-chain state
Understanding of how wallet signers work: EOAs, browser and embedded wallets, smart accounts; personal_sign (EIP-191) and typed data (EIP-712); the EIP-1193 provider; network switching
Hands-on experience with smart wallets: UserOperations, gas sponsored via paymasters, signature validation for contract accounts (ERC-1271)
Experience with Go and TypeScript (Node.js) for production services
Experience processing on-chain events: idempotency, reorg handling, retries
Experience with asynchronous messaging and event-driven design (Kafka, RabbitMQ or NATS): delivery guarantees, ordering, reprocessing
Experience with relational databases (PostgreSQL) and caching (Redis)
Experience designing REST and gRPC APIs: versioning, backward compatibility
Experience with React and TypeScript: rendering model, state management, performance
Understanding of web security fundamentals: XSS, CSRF, CSP, safe handling of signatures and keys in the browser
Ability to read and understand Solidity contracts and the EVM (storage, gas, call semantics, proxy upgrade patterns, access control) well enough to integrate with them safely and review changes
Understanding of common contract vulnerability classes (reentrancy, front-running / MEV, oracle manipulation, signature replay) and how they affect the off-chain side
Experience with containers and orchestration (Docker, Kubernetes) at the level of deploying and debugging your own services
Experience with observability (we use Datadog; experience with Prometheus, Grafana, ELK / Graylog or OpenTelemetry also counts): metrics, logs, tracing and alerting for services and contracts; diagnosing incidents in production
Experience with testing: unit, integration, E2E
Experience with Git, CI/CD (GitLab CI or similar)
Daily hands-on use of AI coding tools (Claude Code, Codex, Cursor) for development and review, including configuring them for a repository
Spoken English at B2 level or higher

Nice to have

Experience with zkSync / ZK Stack and the specifics of the zk-rollup stack
Experience designing, writing and testing smart contracts in Solidity with Foundry; deploying and upgrading them safely
Experience building ERC-4337 infrastructure yourself (bundlers, paymasters); EIP-6963, EIP-5792
Knowledge of DeFi: DEX and AMM mechanics
Knowledge of NFTs and marketplaces: ERC-721, ERC-1155, auction mechanics
Experience with L2 infrastructure: running nodes, indexers, bridges
Experience designing SDKs for external developers
Gaming domain experience

We offer

A comprehensive Benefits Program prioritizing the physical, mental, and emotional well-being of employees and their families
Medical, dental, and vision benefits
PTO
Personalized career roadmap for each employee
Professional development supported through training and educational opportunities
Remote work
Full-time employment
Flexible schedule (10:00–19:00)
Employment agreement (entity or EOR arranged per candidate location)
Salary in currency

Hiring process

Intro call: background, motivation and the role
Technical interview: built directly on the "What you will own" and "Required" sections
Bar raiser: an engineer from outside the hiring team checks that you raise the overall engineering bar