Senior Engineer - SDK

About RudderStack

RudderStack is a warehouse-native customer data platform enabling companies to collect, govern, and activate real-time customer data for analytics, personalization, and AI-powered/agentic applications.

Backed by S28, Kleiner Perkins, and Insight Partners, RudderStack is trusted by leading AI-native companies such as Lovable, Hex, n8n, Vercel, and Seamless, along with multiple Fortune 100 global enterprises.

The JavaScript SDK powers how millions of events enter RudderStack every second. It’s the first touchpoint between developers and our platform—and it must be fast, reliable, and invisible.

You’ll own the SDK end-to-end: architecture, performance, privacy, and developer experience. You’ll work closely with engineering and product teams to ensure every event is captured, transformed, and delivered seamlessly.

Your work will shape how developers around the world collect, trust, and use customer data in the AI era.

About the role

• This is a ground-up opportunity to shape how thousands of developers send data into RudderStack — powering the pipelines that move 300+ billion events every month. You’ll own the SDKs that sit at the heart of our platform — the very first component every customer touches.
• You’ll work with a world-class engineering team tackling deep browser and performance challenges: **cross-browser reliability, bundle optimization, privacy compliance, and real-time delivery at scale**. You’ll learn how data flows from SDKs in the browser to warehouses, through transformations and into AI-ready customer profiles.
• This role blends craft and impact. You’ll write code that lives inside our customers’ products, powering analytics, personalization, and AI systems behind the scenes.
• If you’re the kind of engineer who obsesses over performance, **cares about every byte shipped**, and takes pride in building tools developers love — this is your place.
• Your code will run everywhere. Your users will be developers themselves. And you’ll build the foundation that powers how enterprises interact with their customer data in the AI era.

Why This Role Matters

Every RudderStack customer relies on the SDK to move data from their apps to the warehouse.

When tracking fails, analytics break. When performance drops, user experiences suffer.

You’ll make the invisible visible—ensuring billions of events reach their destinations reliably.

Your work will define trust, performance, and developer happiness across the RudderStack ecosystem.

The Builder's Mindset We Seek

• You care about **craft**—how a few lines of code can impact billions of events.
• You balance speed with quality and simplicity with reliability.
• You debug edge cases across browsers with curiosity, not frustration.
• You see SDKs as a product, not just code.You build with empathy for developers integrating your work in complex environments.

What You'll Master Here

• Cross-browser SDK design (modern + legacy support)
• Lazy loading, tree-shaking, and bundle optimization
• Fault-tolerant event delivery with retries and offline support
• Consent and cookie management under evolving browser restrictions
• Developer tools and debugging utilities that improve customer experience
• Observability and analytics for SDK performance and reliability

Qualifications

• 6+ years of building production-grade SDKs or JavaScript libraries
• Deep understanding of web browser internals—Fetch/XHR, DOM, Storage, Cookies, CORS, CSP, Service Workers
• Strong JavaScript and TypeScript knowledge
• Experience with bundlers (Webpack, Rollup, Vite, ESBuild)
• Proven track record in optimizing performance and reducing bundle size
• Strong testing discipline (Jest, Mocha, Cypress, Playwright)
• Knowledge of privacy and security (GDPR, CCPA, CSP, XSS, encryption)
• Excellent documentation and communication skills