Top Senior Javascript Jobs in Madison, WI

Build end-to-end features in a JS/TS stack, designing scalable backend services and responsive real-time frontends. Improve observability, performance, and reliability, collaborate with product/design, and own full-stack implementation from APIs and data models to UI.

Evaluate AI coding-agent interactions for usefulness, correctness, engineering judgment, explanation quality, and user trust. Provide rigorous, opinionated feedback distinguishing response quality levels and help define best practices for tools such as OpenAI Codex, Claude Code, and Cursor. This contract role requires experienced software engineering judgment rather than production coding.

The role involves leading the development of a high-performance Web SDK for fraud detection and risk management, implementing algorithms for device fingerprinting, and ensuring security and performance optimization.

Develop and maintain high-scale JavaScript and TypeScript monetization solutions using Prebid.js, Prebid Server, Google Ad Manager, and header bidding technologies. Own wrapper architecture, integrations, performance, releases, and reliability. Monitor Core Web Vitals and client-side efficiency while reviewing code, tracking ad tech standards, and contributing to platform improvements. Collaborate independently across a distributed engineering team and resolve production issues.

Design and build full-stack applications that expose AI/ML insights. Develop backend services in Python, RESTful APIs, and containerized microservices. Build high-performance front-end interfaces with React/Vue/Angular. Implement cloud-native solutions on Google Cloud or Azure, manage relational and NoSQL databases, apply testing and CI/CD, and participate in Agile development and architecture sessions.

Maintain and extend long-term supported forks of major JavaScript frameworks. Develop and secure code in JavaScript/TypeScript, backport fixes, triage and patch CVEs, build CI/CD and automation, collaborate with security and OSS contributors, and drive platform reliability and architecture decisions.

Senior full‑stack engineer responsible for building backend services (Node.js/TypeScript) and integrating with frontends (React/Vue). Ship production APIs, collaborate cross‑functionally, own delivery, mentor peers, and develop modular, testable, performant systems across diverse greenfield projects.

The Senior Full Stack JavaScript Developer will build and maintain user interfaces using React and Next.js, integrate with Node.js backends, and guide other developers. Responsibilities include ensuring accessibility, performance, and reliability of features, engaging in code reviews, and collaborating closely with product teams.

Build and maintain Supabase JS/TS SDKs used across runtimes. Author libraries, manage public repos, triage issues, review PRs, keep CI/release automation healthy, own type experience, support realtime/WebSocket semantics, ensure cross-runtime compatibility, write RFCs, docs, and migration guides, and improve SDKs for AI coding agents.