Middle/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.

ABOUT YOU

We are looking for a Middle/Senior Backend Engineer who is passionate about building secure, high-load identity systems to join our Xsolla ID team. The best candidate will be someone who thrives in a fast-paced, highly collaborative, and exceptionally dynamic setting and is excited to develop a next-generation IAM (Identity and Access Management) platform that serves as the foundation for all Xsolla B2C products.

Strong backend development skills in Go are essential, along with experience in building scalable distributed systems and working with authentication/authorization protocols. The ability to design and optimize high-availability services handling millions of users will be key to your success in this role.

If you're passionate about creating reliable, secure identity solutions and love working on strategic platforms that directly impact user experience across gaming ecosystem, we would love to hear from you!

About the project

Xsolla ID is a strategic core service - the centralized identity provider for the entire Xsolla ecosystem. It is not just a login form; it's a comprehensive IAM platform enabling authentication and authorization across all B2C products, including Xsolla Wallet, Xsolla App, Web Shops, and partner integrations.

Tech Stack:

• Language: Go (idiomatic code, concurrency patterns, performance profiling)

• Databases: PostgreSQL (schema design, query optimization, migrations at scale), MySQL, Redis

• Distributed SQL: CockroachDB (multi-region deployments, clock skew handling, survivability trade-offs) for geo-distributed data residency

• Message Streaming: NATS, Kafka (event-driven patterns, consumer groups, at-least-once delivery), RabbitMQ

• Infrastructure: Docker, Kubernetes, Nginx

• Identity Stack: Ory ecosystem (Hydra for OAuth2/OIDC, Kratos for identity management) with a custom Auth API orchestrator and plugin architecture

• Protocols: OAuth 2.0 / OIDC (authorization code + PKCE, client credentials, device flow, token introspection, refresh strategies), WebAuthn

• Web Security: cookie security, CSRF, XSS protection, secure token storage, TLS, secure session management

• Architecture: Microservices, High Availability design

Key Technical Challenges:

• Building Web2 & Web3 authentication flows (OTP, passkeys, biometrics, wallet-based login)

• Implementing custom auth methods without forking Ory

• SSO without third-party cookies

• Zero-downtime migration from legacy Xsolla Login with bidirectional identity sync

• Geo-distributed data residency via CockroachDB

• High availability and scaling for millions of concurrent users

• SDK development and integration with multiple Xsolla products

Responsibilities

• Develop and maintain backend services for the Xsolla ID platform using Go

• Design and implement OAuth 2.0 / OIDC flows (authorization code + PKCE, client credentials, device flow), token introspection, and refresh strategies

• Work with the Ory ecosystem (Hydra, Kratos) and extend the custom Auth API orchestrator and plugin architecture

• Apply web security fundamentals: cookie security, CSRF/XSS protection, secure token storage, TLS, secure session management

• Optimize database queries and ensure high performance under heavy loads (PostgreSQL, MySQL, Redis, CockroachDB)

• Build and maintain microservices architecture with focus on reliability and scalability

• Contribute to zero-downtime migration from legacy Xsolla Login with bidirectional identity sync

• Write clean, well-tested code with comprehensive unit and integration test coverage

• Collaborate with frontend engineers on SDK and widget integration

• Participate in code reviews and contribute to technical documentation

• Support production systems and troubleshoot issues across the authentication stack

QUALIFICATIONS

Required:

• 2+ years of commercial experience with Go

• Strong understanding of PostgreSQL and Redis (query optimization, indexing strategies)

• Working knowledge of OAuth 2.0 / OIDC auth flows (authorization code, client credentials) or strong motivation to learn

• Understanding of web security fundamentals: CSRF, XSS, cookie security, TLS

• Experience with Docker and docker-compose

• Proficiency with Git and collaborative development workflows

• Understanding of Nginx and web server configuration

• Solid experience writing unit tests and maintaining high code quality

• Good English reading skills (technical documentation)

Preferred:

• Understanding of microservices architecture and distributed systems trade-offs (consistency, availability, failure modes)

• Experience with REST API design and documentation (Swagger/OpenAPI)

• Hands-on experience with CI/CD pipelines

• Familiarity with the Ory ecosystem (Hydra, Kratos, Keto) or similar identity management frameworks

• Knowledge of PKCE, client credentials, device flow, token introspection, and refresh-token strategies

• Experience with CockroachDB or other distributed SQL databases (multi-region deployments, clock skew handling)

• Experience with NATS, Kafka, or RabbitMQ for event-driven / message-streaming patterns

• Familiarity with Jira for project management

• Understanding of Kubernetes and container orchestration

• Familiarity with compliance requirements relevant to IAM: SOC 2, ISO 27001, GDPR data minimization, audit logging

• Practical, up-to-date experience with modern AI tools (e.g. Claude, Copilot, Cursor) for code generation, review, and accelerating day-to-day engineering work