Principal Software Engineer

Xometry is looking for a Principal Software Engineer to join our Partner Ecosystems team. This team builds the high-performance integration layer that embeds Xometry’s AI-native marketplace directly into the world’s leading CAD and PLM platforms.

You will be the primary technical architect for our landmark partnership with Siemens. This is not a standard plug-in project; you will be responsible for extracting Xometry’s core AI engines (DFM and IQE) and natively embedding them into the Siemens Designcenter and Teamcenter ecosystems. Your work will enable a "science fiction speed" workflow where designers receive real-time manufacturability and pricing feedback on native 3D geometry without ever leaving their Siemens environment.

This role requires a hybrid schedule (3 days a week) at our North Bethesda, MD or Waltham, MA office location.

• Software Development and Technical Craft: You will lead the discovery, architectural design, and adoption of the embedded Siemens integration. You'll introduce best practices for handling native 3D geometry data flows and ensure our systems are extensible, scalable, and capable of delivering real-time AI insights at the moment of design.
• AI Fluency: You will leverage AI tools to accelerate the development of geometry-processing pipelines and collaborate with our Data Science team to ensure the "IQE" (Instant Quoting) engine performs with sub-second latency within the Siemens UI. In addition, you’ll define and evangelize the organization's AI fluency standards, coaching Staff and Senior engineers on integrating AI tooling into architecture, design, and development workflows to drive measurable productivity and quality outcomes.
• Problem Solving and Decision Making: You will tackle complex issues involving deep technical coupling between Xometry’s marketplace and Siemens’ PLM environment. You'll exercise judgment in selecting the right methods for ring-fenced data governance and "one-click" order placement within enterprise-grade security constraints.
• Scope and Impact: You are responsible for leading cross-team decision-making and executing multi-quarter roadmaps. Your work directly impacts Xometry’s strategic edge, moving us from lightweight HTML snippets to a deep, native integration that eliminates the need for design file exports.
• Collaboration and Communication: You will act as the primary technical point of contact for Siemens’ engineering teams. You'll motivate internal Xometry teams to embrace the vision of a "unified digital thread" and mentor senior and mid-level engineers through complex design reviews.
• Operational Excellence: You will own the reliability and security of the integration microservices, ensuring that "click-to-buy" functionality is bulletproof and that monitoring/alerting covers the unique lifecycle of enterprise PLM transactions.

• 8–12+ years of professional software development experience, with a proven track record of leading complex, multi-quarter initiatives.
• Expert Technical Proficiency: Deep experience in our stack: Python (backend services, APIs), React/TypeScript (embedded UIs), and AWS cloud infrastructure.
• Architectural Mastery: Significant experience with system architecture, microservices design, and distributed systems, specifically those involving high-volume data exchange between disparate enterprise ecosystems.
• Integration Expert: A track record of introducing architectural patterns adopted across multiple teams and building "enterprise-grade" integrations that go beyond simple API wrappers.
• Education: Bachelor’s in Computer Science, Engineering, or a related field, or equivalent practical experience.

• CAD/PLM Domain Expertise: Experience with Siemens (NX, Solid Edge, Teamcenter), Dassault (SolidWorks), or Autodesk ecosystems.
• 3D Geometry Background: Understanding of B-Rep, mesh formats, and the complexities of 3D modeling workflows.
• Marketplace Engineering: Experience in e-commerce, fintech, or B2B marketplaces where "click-to-buy" precision is critical.
• Security Mindset: Experience building dedicated-tenant or ring-fenced solutions for high-security enterprise clients.

• The base pay range for this role is $200,000 - $225,000. The total compensation package includes base, bonus, and equity.
• Comprehensive benefits package including 401k match, medical, dental, and vision insurance, and generous paid time off.
• A stipend for catered lunch on Tuesdays and Thursdays.

The estimated base salary range for new hires into this role is $200,000 - $225,000 annually + annual bonus depending on factors such as job-related skills, relevant experience, and location. We also offer a competitive benefits package, including 401(k) match, medical, dental and vision insurance; life and disability insurance; generous paid time off including vacation, sick leave, floating and fixed holidays, maternity and bonding leave; EAP, other wellbeing resources; and much more.

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