Software Engineer

ABOUT YOU   We are looking for a Software Engineer, Web3 for Xsolla ZK, Xsolla's Web3 ecosystem on a zkSync-based L2. This will involve working on: 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.   ABOUT US   Xsolla is a global commerce company with robust tools and services to help developers solve the inherent challenges of the video game industry. From indie to AAA, companies partner with Xsolla to help them fund, distribute, market, and monetize their games. Grounded in the belief in the future of video games, Xsolla is resolute in the mission to bring opportunities together, and continually make new resources available to creators. Headquartered and incorporated in Los Angeles, California, Xsolla operates as the merchant of record and has helped over 1,500+ game developers to reach more players and grow their businesses around the world. With more paths to profits and ways to win, developers have all the things needed to enjoy the game. For more information, visit xsolla.com. Responsibilities:

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

Qualifications & Skills:

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

How We Work:

Decisions in writing. Significant technical decisions are written up as an RFC or ADR that lays out the options and trade-offs. We discuss the document, not a blank whiteboard.

AI is part of everyday engineering. We use AI coding tools for development and review, and we treat configuring them for a codebase as real engineering work.

The team. You will work alongside product managers, designers, smart contract, backend and frontend engineers, QA and DevOps.

How We Hire:

1. Intro call. Your background, your motivation and the role.

2. Technical interview. Built directly on the Responsibilities and Qualifications & Skills sections above. We won't ask about anything this posting doesn't promise.

3. Bar raiser. An engineer from outside the hiring team checks that you raise the overall engineering bar.

Benefits: We are passionate about fostering a supportive environment for our team, so we prioritize the physical, mental, and emotional well-being of our employees and their families through a comprehensive Benefits Program. This includes 100% company-paid medical, dental, and vision plans, unlimited Flexible Time Off, and a personalized career roadmap for each employee. By investing in professional development through training and educational opportunities, we ensure that our team thrives both personally and professionally. Together, we’re not just building a business; we’re cultivating a community that values creativity, collaboration, and the transformative power of play.   Equal Employment Opportunity Statement: Xsolla is an equal opportunity employer. We celebrate diversity and are committed to creating an inclusive environment for all employees. We do not discriminate based on race, color, religion, sex, national origin, age, disability, sexual orientation, gender identity, or any other characteristic protected by law. We consider qualified applicants with criminal histories in accordance with the Fair Chance Act.   Criminal History Consideration: For the Software Engineer, Web3 position, we will conduct a background check that may include the following: Criminal history check Employment verification Education verification   Relevance to Job Responsibilities: The background check is relevant to this position because of the following role responsibilities: Accessing confidential company data Ensuring compliance with regulatory requirements   Rights Under the Fair Chance Act: Applicants are encouraged to inquire about their rights under the Fair Chance Act. If you have questions regarding our hiring practices, please contact careers@xsolla.com.