# Senior/Staff JavaScript Developer - Web SDK

**Company:** [Oscilar](https://hotfix.jobs/companies/oscilar)
**Location:** Remote
**Role:** Frontend Engineering
**Salary:** R$394k – R$574k/yr
**Experience:** 8+ years
**Skills:** JavaScript, TypeScript, REST APIs, Git, Web Sdks, Browser Apis, Data Privacy, Encryption, Hashing, Obfuscation, Cross-Browser Compatibility, webpack, Babel, Rollup, CI/CD
**Posted:** 2026-02-21

> Leads the design, development, and optimization of a browser-based Web SDK for device fingerprinting, behavioral analytics, and fraud prevention. Requires deep JavaScript and TypeScript expertise, browser-platform knowledge, SDK development experience, and 8+ years of web development experience.

## Job Description

## Responsibilities
- Lead the development and maintenance of a high-performance Web SDK for collecting and analyzing browser and device-related data.
- Design and implement algorithms for unique device fingerprints and behavior-based insights, including gestures, keyboard, and mouse interactions.
- Build and maintain CI/CD pipelines with automated cross-browser testing and release cycles.
- Optimize SDK performance to minimize resource usage and ensure a seamless user experience.
- Stay current on web technologies, security practices, and industry trends.
- Develop clean, maintainable, and well-documented code.
- Conduct code reviews and mentor junior engineers.
- Collaborate with product managers, designers, and QA engineers.
- Embed data privacy and security principles into the SDK’s design and implementation.
- Drive innovation in browser-based risk, fraud detection, and device analytics solutions.

## Requirements
- Proficiency in JavaScript (ES6+), TypeScript, REST APIs, Git, and version control tools.
- Extensive experience designing and maintaining Web SDKs or libraries focused on data collection, tracking, or analytics.
- Deep understanding of browser environments, browser APIs, and efficient browser-data handling.
- Strong knowledge of data privacy, encryption, hashing, and obfuscation techniques.
- Experience building solutions compatible with multiple browsers and devices.
- Familiarity with server-side technologies and RESTful APIs for data retrieval and storage.
- Proficiency with modern build tools such as Webpack, Babel, or Rollup.
- Bachelor’s degree in computer science, software engineering, or a related field, or equivalent experience.
- 8+ years of web development experience, including at least 3 years building and maintaining SDKs.
- Proven contributions to open-source projects or relevant work showcased on platforms such as GitHub.

## Nice-to-haves
- Experience with AI-driven analytics, risk systems, or fraud prevention technologies.
- Familiarity with JavaScript SDKs, gestures, and interaction-data processing.
- Experience in high-scale, distributed environments.

## Compensation and Benefits
- Competitive salary and equity packages, including a 401(k).
- Remote-first culture.
- Employer-covered comprehensive health, dental, and vision insurance with a top-tier plan for employees and dependents in the US.
- Unlimited PTO.
- AI-first technical environment.
- Family-friendly culture with regular team events and offsites.
- Professional development opportunities.
- Opportunity to help protect online transactions and make the internet safer.

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**Apply:** https://hotfix.jobs/jobs/d8943d81-9996-483d-b100-64bf55407163
**Canonical:** https://hotfix.jobs/jobs/d8943d81-9996-483d-b100-64bf55407163