Senior Software Engineer, Web SDK

The Role

We are looking for a Senior Software Engineer to serve as a technical pillar for our client-side document SDK. This is not a standard UI/UX role; you will be architecting the engine that powers document rendering, programmatic manipulation, and collaborative workflows for millions of users.

As a senior leader on the team, you will steward our "Core" minified engine while maintaining our open-source UI layer. You will be responsible for navigating deep technical ambiguity, writing comprehensive design documents, and making high-stakes trade-off decisions regarding performance, memory management, and API design. If you enjoy the challenge of working with WebAssembly , concurrent workflows (Web Workers), and complex binary file formats (PDF, DocX , XLSX), this role is for you.

Responsibilities

• System Architecture: Lead the design and evolution of the WebViewer SDK, ensuring a clean separation between our open-source UI ( https://github.com/PDFTron/webviewer-ui) and our high-performance "Core" engine.
• Technical Leadership: Drive the "Design Doc" culture. You will be responsible for planning and executing complex features, from programmatic redaction to real-time collaboration syncing.
• Performance Engineering: Optimize the SDK to handle documents of extreme size and complexity, managing memory leaks, rendering bottlenecks, and expensive programmatic functions.
• Cross-Functional Collaboration: Partner with Product, Sales, and Solution Engineers to translate high-level customer needs into robust technical roadmaps.
• Mentorship & Quality: Set the bar for code quality through rigorous PR reviews, architectural guidance, and the promotion of strong testing fundamentals.
• Developer Advocacy: Our customers are developers. You will ensure our APIs are intuitive, our documentation is world-class, and our SDK is a joy to integrate.
• Customer experience is paramount to us. We regularly collaborate with software developers, project and product owners, UI/UX, support, sales, and solution engineer teams to design new features and improve user experience.
• Our customers are other developers, so we research and utilize the latest technologies, write concise technical documentation, and informative blogs.

Requirements

• Experience: 5–10 years of professional software development experience, with a proven track record of shipping complex web-based products or platforms.
• Architectural Mindset: Deep understanding of common design patterns and methodologies. You should be comfortable discussing the trade-offs between different state management patterns and API structures.
• Web Fundamentals: Expert-level knowledge of JavaScript/TypeScript and how the web client-server model operates at a deep level (e.g., request lifecycles, browser rendering engines, and binary data handling).
• Concurrency & Performance: Experience managing concurrent workflows, particularly with Web Workersand WebAssembly ( Wasm ). You understand how to offload heavy computation without blocking the main thread.
• Testing Excellence: Beyond just "writing tests," you have a robust understanding of testing strategy. Experience with Playwright, Storybook, and Jest is preferred, but a mastery of testing fundamentals (unit, integration, and E2E) is required.
• Communication: Exceptional technical writing and verbal communication skills. You can explain complex architectural trade-offs to both engineers and non-technical stakeholders.
• Navigating Ambiguity: A proven ability to take a vague product requirement and turn it into a concrete, executable technical plan.

Preferred Experience

• Experience building SDKs, Libraries, or Open-Source project s where API stability and developer experience are paramount.
• Familiarity with document-specific technologies (PDF specification, OOXML, or canvas-based rendering).
• Experience with low-level languages (C++, Rust, or Go) that compile toWebAssembly.
• Deep knowledge of Collaborative Frameworks (CRDTs,WebSockets, or operational transform).
• Experience building accessible UIs
• Experience with backend(Node.js, PHP, etc.).
• Experience with databases (NoSQL or SQL).
• Experience with mobile applications (Android / iOS).

Benefits

• Competitive salary commensurate with experience & qualifications.
• A comprehensive extended benefits package.
• A great team environment and resources, supporting you to do the best work of your life and providing unlimited career growth potential.
• Highly autonomous and entrepreneurial environment.
• Annual recurring WFH allowance for you to purchase items you need for your home office.
• On going support for learning development so you can continue to master your craft.
• Work with the hardware you're most comfortable with (Windows or Mac)
• Diverse and inclusive workplace where we all learn from each other.
• Excellent work-life balance with a flexible remote work environment.

Company Description

As the industry-leading provider of document software development (SD