We’re rebuilding the internet's data layer for the AI era. This starts with systems that analyze billions of events and make millions of decisions every day, enabling some of the largest brands in the world to leverage their data. Our platform dynamically engages users, orchestrates data directives across an entire ecosystem, and takes intelligent action on AI-driven insights. Protecting highly personal data across the data ecosystem requires infrastructure that can operate at the speed and complexity of modern, massively distributed systems. The result: real-time control and intelligence across billions of data interactions for companies, and direct control for you over how your personal data is collected and used.

Ketch is a well-funded Series B startup backed by top-tier investors and led by a leadership team with multiple exits. We’re passionate builders who work shoulder-to-shoulder with customers to understand their deepest data challenges and build elegant, scalable solutions.

Join us to build distributed systems infrastructure that must never fail at massive scale, in the hardest runtime environment imaginable. We’re creating SDKs that integrate across the entire web and mobile stack, systems that process billions of signals a day, and real-time distributed infrastructure that pushes what’s possible.

Role Overview

As a Senior Frontend Engineer, Ketch SDKs, you’ll own the runtime that powers the modern internet. You’ll design and maintain SDKs that process millions of events per day and emit billions of signals to platforms like Google, Meta, Snowflake, Datadog, and FullStory enabling data collection that respects user choices while powering the modern ad-tech ecosystem. Every network request, every consent signal, every event flows through the infrastructure you build. If Ketch ever goes down, major platforms you use daily may go down with it. The stakes are real.

This is infrastructure at an impossible scale, in the hardest runtime environment imaginable. You’ll tackle performance, privacy, and reliability head-on, building systems that can’t fail and architectures that ripple through Fortune 500 production environments. We operate with deep personal ownership which means that you’ll solve problems from first principles, drive end-to-end solutions, and define the technical direction for client-side data governance at scale. You’ll design SDKs used by thousands of engineers, integrating with the entire web and mobile stack, shaping the backbone of a free and fair internet.

This is a hybrid role based out of the San Francisco HQ 3 days a week.

What You’ll Own

Design and evolve the core Ketch SDK runtime for consent orchestration, event tracking, rule evaluation, and platform integration at massive scale.
Optimize SDK performance under impossible constraints and enforce deterministic client-side data governance across 50+ browsers/OS combinations, intercepting and managing network requests, cookies, and storage.
Build APIs and tooling for thousands of engineers, making complex integrations simple, secure, and impossible to misuse.
Extend SDKs for custom integrations, multi-platform routing, adtech connectivity, and AI-driven privacy telemetry.
Simulate real-world network interactions with emulators and pipelines that feed AI models for privacy risk detection.
Collaborate across product, design, and customer success, mentor engineers, and drive architectural excellence across the frontend team.

What We’re Looking For

Deep expertise in JavaScript & TypeScript (ES6+), browser APIs, event loops, closures, and high-performance client-side coding across diverse runtime environments.
Proven experience building SDKs and JavaScript tags deployed on customer websites, integrating with internal and external platforms under production pressure.
Mastery of browser architecture and client-side systems: rendering pipeline, network stack, storage APIs, cross-origin communication, and deterministic data flow governance.
Performance and reliability wizardry: profiling, benchmarking, optimizing, and debugging async race conditions across distributed client-side systems.
Systems thinking and build tooling experience: Webpack, Rollup, ESBuild, ESM/CommonJS/UMD, polyfills, and managing browser inconsistencies or third-party script conflicts.
Collaboration, mentorship, and product-minded ownership: articulate technical decisions, influence stakeholders, drive pragmatic solutions, and elevate teams through code reviews and knowledge sharing.
Bonus skills: mobile SDKs (iOS/Android/React Native), ad-tech or mar-tech platform experience, privacy/security engineering, or open-source contributions.

Tech Stack

Frontend: TypeScript, React, Rollup, ESBuild, Jest, Playwright
Infrastructure: AWS (Lambda, CloudFront, S3), Docker, TerraformIntegrations: Google Analytics, Meta, Snowflake, Datadog, FullStory, 100+ other platforms
Observability & Telemetry: Datadog, Sentry, custom pipelines processing billions of events daily
CI/CD & Delivery: GitHub Actions, automated pipelines, feature flags
Mobile / Cross-Platform: iOS/Android SDKs, React Native (plus polyfills and platform-specific optimizations)

170000 - 210000 USD a year

The estimated base salary range for this position is $170,000 to $210,000, which does not include the value of benefits or a potential equity grant. A wide range of factors are considered in making compensation decisions, including but not limited to skill sets, market conditions, experience and training, licensure and certifications, and business and organizational needs

We do not accept resumes from headhunters, placement agencies, or any 3rd parties. All submissions will be considered a gift and no fee will be due.

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