Senior Frontend Platform Engineer, Design Systems

About Us

At Lang Chain, our mission is to make intelligent agents ubiquitous. We build the foundation for agent engineering in the real world, helping developers move from prototypes to production-ready AI agents that teams can rely on. We began as widely adopted open-source tools and have grown to also offer a platform for building, evaluating, deploying, and operating agents at scale.

With $125M raised at Series B from IVP, Sequoia, Benchmark, CapitalG, and Sapphire Ventures, we’re at a stage where we’re continuing to develop new products, growth is accelerating, and all team members have meaningful impact on what we build and how we work together. Lang Chain is a place where your contributions can shape how this technology shows up in the real world.

Today, our platform includes Lang Smith (Observability, Evaluation, Deployment, Fleet, and Sandboxes), our open source frameworks (Lang Chain, Lang Graph, and Deep Agents), and the newly launched Lang Smith Engine for autonomous agent improvement. We have 100M+ monthly open source downloads, 6,000+ active Lang Smith customers, and 5 of the Fortune 10 use Lang Smith in production (+ 35% of the Fortune 500 overall), including teams at Klarna, Clay, Coinbase, Workday, Lyft, Cloudflare, Harvey, Rippling, Vanta, Linked In, , Nvidia, and Bridgewater.

At Lang Chain, our mission is to make intelligent agents ubiquitous. We build the foundation for agent engineering in the real world, helping developers move from prototypes to production-ready AI agents that teams can rely on. We began as widely adopted open-source tools and have grown to also offer a platform for building, evaluating, deploying, and operating agents at scale.

Today, Lang Chain, Lang Graph, Lang Smith, and Agent Builder are used by teams shipping real AI products across startups and large enterprises. Millions of developers trust Lang Chain to power AI teams at companies like Replit, Clay, Coinbase, Workday, Lyft, Cloudflare, Harvey, Rippling, Vanta, and 35% of the Fortune 500.

With $125M raised at Series B from IVP, Sequoia, Benchmark, CapitalG, and Sapphire Ventures, we’re at a stage where we’re continuing to develop new products, growth is accelerating, and all team members have meaningful impact on what we build and how we work together. Lang Chain is a place where your contributions can shape how this technology shows up in the real world.

Lang Chain is building the infrastructure that powers the next generation of AI applications. Our tools are used by thousands of developers and teams to build, debug, and ship production-grade LLM-powered products.

As our product surface area grows, so does the need for a cohesive, scalable, and high-quality UI foundation. That’s where Design Systems comes in. We’re looking for a Design Systems Engineer to help build, own, and evolve Lang Chain’s component library—the foundation that our frontend teams rely on to ship fast without sacrificing quality, accessibility, or consistency.

This role sits at the intersection of Design and Engineering. You’ll work closely with designers, product engineers, and platform teams to turn design intent into robust, reusable components and tooling that scale across the product.

You’ll have ownership, influence, and your work will be directly consumed across Lang Chain’s products.

• Build and own Lang Chain’s component library
• Design and implement reusable, composable React components that are flexible, accessible, and production-ready
• Partner closely with designers to translate design systems, tokens, and interaction patterns into code
• Build reliable UI quality systems
• Develop design system tooling and improve workflows around theming, tokens, versioning, testing, and component discovery (e.g. Storybook)
• Make thoughtful architectural decisions that enable accessibility, performance, consistency, and maintainability across Lang Chain’s UI stack
• Improve UI build and test workflows
• Optimize build performance, bundling strategy, and package versioning for the component library
• Maintain tooling for testing, dependency management of the UI app

• Strong experience building…