Senior iOS Engineer

Knot • New York, NY

3d • Onsite

About The Position

We are looking for a Senior iOS Engineer to help shape the architecture, reliability, and performance of our SDK, which powers mission-critical experiences for some of the largest FinTechs in the world.
You will work across the entire lifecycle of our iOS SDK, from design to release. This includes shaping how we profile performance, how we catch issues before they ship, how we test our public APIs, and how we produce documentation that makes our SDK easy to integrate. You will collaborate with product and engineering teams across the company, and you will help represent and advocate for our SDK both internally and externally.

Requirements

• Strong debugging skills and proficiency with native profiling tools
• Deep understanding of memory allocation, leaks, CPU usage, and asynchronous patterns
• Experience building asynchronous and multithreaded architectures
• Ability to design, validate, and document public SDK APIs
• Strong unit testing mindset and experience uncovering failure modes and edge cases
• Familiarity with mobile CI/CD pipelines and the desire to improve them
• Comfortable executing thorough QA validation prior to releases
• Clear and effective communication with cross-functional teams
• Experience writing and debugging UI automation tests
• Familiarity with feature flagging and controlled rollout strategies
• Deep experience with WKWebView including navigation, messaging, resource handling, and hybrid debugging
• Proficiency with Swift and Swift Concurrency
• Experience with ARC, Instruments, and iOS frameworks
• Experience building and maintaining frameworks or Swift Packages
• Familiarity with Xcode build tooling and performance optimization

Responsibilities

• Lead and contribute to the architecture, design, and optimization of the iOS SDK
• Profile, debug, and improve memory usage, CPU consumption, concurrency, and overall runtime efficiency
• Design stable, predictable public APIs and produce documentation that supports developers integrating our SDK
• Strengthen test coverage with unit tests, UI automation, integration testing, and performance testing
• Co-own the mobile CI/CD workflows that ensure safe, reliable, and repeatable releases
• Investigate production issues with attention to detail and implement long-term safeguards
• Advocate internally and externally for best practices around integration, performance, and reliability
• Participate in cross-team technical planning and represent the platform’s needs
• Evangelize the SDK and help educate teams on its capabilities and usage
• Contribute to building an engineering culture rooted in clarity, ownership, and thoughtful design

Benefits

• Competitive base salary + up to 20% annual bonus + generous early employee equity + benefits
• 100% medical, dental, and vision insurance coverage for you and your dependents (U.S.)
• Unlimited PTO
• Parental leave
• Beautiful NYC office in the heart of Flatiron
• Herman Miller Aeron desk chair
• Food (snacks, frequent lunches & often dinner for those working late)

What This Job Offers

• Job Type: Full-time
• Career Level: Mid Level
• Education Level: No Education Listed
• Number of Employees: 11-50 employees