Software Engineer

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

smart wallets built on account abstraction;

SDKs that game studios and partners use to bring players on-chain;

infrastructure backend services for tokenizing in-game items and currencies;

ecosystem dApps: a DEX , an NFT marketplace and an auction.

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

WHAT YOU WILL OWN

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

WHAT YOU WILL DO

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 Experience

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 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