Senior Backend Engineer

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.

The role

THE ROLE

We are hiring a Senior Backend Engineer for two platform products:

• Xsolla ID is the identity and authentication platform behind sign-in, account management and SSO across Xsolla products.
• Xsolla ZK is Web3 wallet infrastructure: smart wallets and account abstraction on a zkSync-based L2.

Both products sit on users' most sensitive flows, logging in and signing transactions, and other Xsolla teams build on top of them.

WHAT YOU WILL OWN

• The backend services of your product area end to end: design, implementation, release and production operation, including on-call
• Architecture across services: service boundaries, integration contracts and data ownership. You make these decisions and justify them in writing
• Reliability and security of critical flows: SLOs, failure handling, protection of user data and credentials
• Service performance and cost under load

WHAT YOU WILL DO

• Design and build services and APIs (REST, gRPC) for authentication, account management and wallet operations
• Define service boundaries and integration contracts with other Xsolla teams
• Design data models and storage; optimize schemas and queries
• Build event-driven and asynchronous workflows
• Own observability: metrics, logs, tracing and alerting, and act on what production tells you
• Take part in on-call, incident response and post-mortems
• Improve the engineering environment: CI/CD, infrastructure-as-code, testing
• Review code
• Set up and maintain AI tooling in the repositories (Claude Code, Codex, Cursor: rules, context, harness) so the team uses it effectively

Responsibilities

• Language and platform
  • 5+ years of commercial backend development
  • Go: idiomatic code, concurrency (goroutines, channels, context and cancellation), memory and performance profiling (pprof)

  Data

  • Relational databases (PostgreSQL, MySQL): schema design, indexes, query plans, transactions and isolation levels, safe migrations
  • Caching (Redis): when to cache, invalidation, consistency trade-offs

  Distributed systems

  • Service architecture and distributed-systems trade-offs: consistency, availability, idempotency, retries, failure modes
  • Asynchronous messaging and event-driven design (Kafka, RabbitMQ or NATS): delivery guarantees, ordering, reprocessing

  APIs

  • Designing REST and gRPC APIs: versioning, backward compatibility, contract documentation (OpenAPI / Swagger, Protobuf)

  Security and identity

  • Application security: common vulnerability classes (OWASP Top 10), secrets management, safe handling of user data
  • OAuth 2.0 / OIDC from the server side: flows, tokens, sessions

  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; diagnosing incidents in production

  Engineering practices

  • Testing: unit, integration, contract
  • 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

  • • Reading technical documentation in English

Nice to Have

• Web3 backend experience: blockchain integration, wallet infrastructure, account abstraction
• High-load systems
• Cloud platforms (GCP, AWS or Azure) and infrastructure-as-code
• NoSQL databases (MongoDB or similar)
• Domain experience in gaming, e-commerce, fintech or payments

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.

HOW WE HIRE

1. Intro call. Your background, your motivation and the role.
2. Technical interview. Built directly on the What you will own and Required 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.

THE TEAM

You will work alongside product managers, designers, backend and frontend engineers, QA and DevOps.