Principal Engineer — DevX & AI

**ABOUT YOU** We are looking for a Principal Engineer to take architectural ownership of the agent-readable Shop Builder platform. This is the most senior individual contributor role on the DevX and AI team, and the decisions you make here — which surfaces to expose, which formats to support, which standards to set — will bind the platform for years. You are not a manager, but your influence is org-wide. You define how developers and AI agents interact with Shop Builder's foundational capabilities: UI as Data, custom blocks, themes, data binding, catalog, payments. You are the technical authority on what the platform exposes and how, and you are deeply hands-on with the hardest parts of that work. **ABOUT US** Xsolla is a global payments and commerce platform for the games industry, used by thousands of publishers to monetize, distribute, and operate their titles worldwide. Shop Builder is Xsolla's storefront platform — used by publishers and game developers to launch and operate game shops, from straightforward catalog and webshops to fully custom storefronts built headless on our backend. For more information, visit . The DevX and AI team owns the public APIs, documentation, and AI features that give developers — and AI agents — the full surface they need to customize and extend Shop Builder. This is a net-new team of seven, standing up to fill a real gap: no dedicated team has owned the developer surface end to end. That changes now. ### Responsibilities - Own the technical architecture of the agent-readable Shop Builder platform: which APIs to expose, in what shape, through which surfaces (REST, SDK, MCP, CLI). - Define the interface contracts that LLMs and developers interact with — React component APIs, custom block schemas, theme tokens, data binding formats — and maintain them with the rigor of a public API. - Design and lead delivery of the MCP server that allows AI agents (Claude Code, Cursor, etc.) to build, deploy, and operate Shop Builder storefronts end-to-end without the editor in the loop. - Architect the CLI and local development environment: how developers scaffold projects, iterate locally, preview changes, and push to production. - Define the deploy, versioning, and rollback model for developer-published content — custom blocks, themes, and layouts. - Design the sandbox and preview environment system so agents and developers can iterate without touching live partner sites. - Set the documentation standard: written for LLMs and humans as first-class users, maintained from single canonical sources and published to every surface (CLI help, dev docs, MCP tool descriptions, AI context). - Lead the eval harness architecture: how the team measures whether an LLM-generated block, theme, or layout is correct before it ships. - Collaborate with Principal/Staff Engineers across payments, auth, live ops, and catalog to pull inbound capabilities into coherent developer-facing surfaces. - Serve as the technical bar-raiser for the team: define code standards, review critical implementation decisions, and mentor the Tech Lead and engineers. - Contribute to hiring and define the technical culture of the team from day one. ### Qualifications & Skills - 10+ years of professional engineering experience, with a demonstrated track record as a Staff or Principal engineer who has shaped platforms, APIs, or developer tooling used by external builders. - Deep expertise in designing and shipping public APIs and SDKs, including versioning strategy, backwards compatibility, and developer ergonomics — strong opinions about what makes an API delightful vs. painful. - Expert-level proficiency in JavaScript/TypeScript and React — the primary interface language for LLMs and developers on this platform. - Hands-on experience building CLI tooling and local developer workflows (scaffolding, hot reload, file-based config, deploy commands). - Solid understanding of the Model Context Protocol (MCP) or equivalent agentic tool-use interfaces, and practical experience building tools that AI agents can reliably invoke. - Experience building systems at global scale on cloud infrastructure (AWS or GCP), with deep knowledge of containerization, CI/CD, and infrastructure-as-code. - Ability to write and reason about LLM-friendly documentation and API surfaces: you understand that token-efficiency, predictability, and schema clarity matter as much as human readability. - Exceptional technical communication: clear RFCs and ADRs, productive architecture reviews, and the ability to explain second-order consequences to engineering and business leadership. - Comfort operating in a greenfield context — you define the structure rather than inherit it. ### Nice to Have - Prior experience in game tech, digital commerce, or storefront platforms — understanding the publisher/developer relationship and headless vs. hosted deployment patterns. - Experience building platforms where AI agents are a first-class user: MCP servers, LLM tool registries, agent eval pipelines. - Familiarity with Figma's plugin/component API, design token standards, and design-to-code pipelines. - Contributions to open-source developer tooling, SDK frameworks, or API standards. - Background in block or extension marketplace design: sandboxing third-party code, schema validation, publisher ecosystems. - Published technical writing, conference talks, or influential community presence in developer tooling or AI-native development.