Sr./Staff JavaScript Developer - Web SDK

🏢 About Oscilar

Oscilar is a leading AI Risk Decisioning platform built to protect digital transactions across fintechs, digital banks, and modern enterprises. Founded by tech veterans from Meta, Uber, and Confluent, Oscilar provides engineering teams with real-time fraud detection, credit risk decisioning, and compliance intelligence at scale.

🎯 The Role

As a Staff JavaScript Developer on the Device and Behavior team, you will lead the design, development, and performance optimization of Oscilar's core Web SDK. This is not a traditional UI application role—you will work directly with browser runtime internals, telemetry capture, behavioral analytics, and device fingerprinting to detect fraud and assess risk in real time.

🛠️ Tech Stack

• JavaScript (ES6+) & TypeScript
• Browser Runtime Internals & DOM APIs
• Bundlers (Webpack, Rollup, Babel)
• Automated Cross-Browser Testing & CI/CD
• Client-Side Cryptography & Obfuscation
• RESTful Ingestion APIs

💼 What You'll Do

• Lead the development and maintenance of a lightweight, highly performant Web SDK for browser-level data collection.
• Design and implement resilient algorithms for unique device fingerprinting and behavioral signal analysis (mouse, touch, gestures, and keystroke metrics).
• Build automated cross-browser testing harnesses and streamlined CI/CD release pipelines.
• Profile and optimize SDK execution to minimize CPU and memory footprint across diverse consumer web applications.
• Embed privacy-by-design, cryptographic hashing, and data obfuscation techniques into telemetry pipelines.
• Conduct architecture reviews and mentor fellow developers on library design and browser runtime behaviors.

✅ What You'll Need

• 8+ years of web engineering experience, with at least 3+ years dedicated to building and maintaining client-side SDKs or published libraries.
• Deep mastery of modern JavaScript, TypeScript, and browser execution environments.
• Extensive experience configuring and tuning bundlers like Webpack, Rollup, or Babel.
• Strong track record of ensuring cross-browser compatibility across desktop and mobile devices.
• Familiarity with client-side security principles, data privacy compliance, encryption, and payload protection.
• Excellent problem-solving skills and the ability to operate autonomously in a fast-paced, remote-first environment.

🌟 Nice to Have

• Prior experience building anti-fraud, bot detection, or identity verification SDKs.
• Familiarity with high-throughput ingestion pipelines and distributed backend systems.
• Contributions to open-source developer libraries or developer tooling.