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.
The role
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
Required
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
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