Software Engineer

XsollaJob.bopublished 10/20/2026

Must-have:TypeScriptReactNode.jsGitDockerKubernetesFrontendBackendFullstackCI/CDAIGamingSecuritySenior

We are hiring a Software Engineer, Web3 for Xsolla ZK, Xsolla's Web3 ecosystem on a zkSync-based L2. It includes:

This is a senior fullstack role: you work across backend, frontend and smart contracts.

Features end to end: backend, frontend and production
The on-chain / off-chain architecture of your product: what lives in contracts, what lives in services, and how the two stay consistent. You make these decisions and justify them in writing
Security and correctness of what you ship: signing flows, interactions with contracts that hold user assets, keys and secrets
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

5+ years of commercial software development, with senior-level production experience across backend and frontend
dApps that you shipped to production and maintained

Web3 libraries and wallets

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
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)

Backend

Go and TypeScript (Node.js) for production services
Processing on-chain events: idempotency, reorg handling, retries
Asynchronous messaging and event-driven design (Kafka, RabbitMQ or NATS): delivery guarantees, ordering, reprocessing
Relational databases (PostgreSQL) and caching (Redis)
Designing REST and gRPC APIs: versioning, backward compatibility

Frontend

React and TypeScript: rendering model, state management, performance
Web security fundamentals: XSS, CSRF, CSP, safe handling of signatures and keys in the browser

Smart contracts

Reading and understanding Solidity contracts and the EVM (storage, gas, call semantics, proxy upgrade patterns, access control) well enough to integrate with them safely and review changes
Common contract vulnerability classes (reentrancy, front-running / MEV, oracle manipulation, signature replay) and how they affect the off-chain side

Operations

Containers and orchestration (Docker, Kubernetes) at the level of deploying and debugging your own services
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

Engineering practices

AI-assisted engineering

Daily hands-on use of AI coding tools (Claude Code, Codex, Cursor) for development and review, including configuring them for a repository

English

Nice to have

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