Software Engineer

ABOUT XSOLLA

Xsolla is a global video game commerce company headquartered in Los Angeles. It helps developers from indie to AAA fund, distribute, market and monetize their games, and acts as merchant of record for 1,500+ developers worldwide. For more information, visit xsolla.com.
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-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


Testing: unit, integration, E2E


Git, CI/CD (GitLab CI or similar)


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


Spoken English at B2 level or higher
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

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, Codex, Cursor: rules, context, harness) so the team uses it effectively