Senior iOS Engineer — SDK Architecture & Performance

Knot API; New York (NY); Hybrid; USD 140,000 - 190,000; Full time

Benefits offered by this job

Competitive compensation

Annual bonus

Equity

Excellent benefits

NYC office in Flatiron

Job summary

Knot seeks a Senior iOS Engineer to shape the architecture and reliability of our iOS SDK powering fintech experiences. You will work end-to-end from design to release, profiling performance, catching issues early, and drafting documentation for easy integration.

You will collaborate with product and engineering across the company, advocate for best practices, and help scale our mobile platform with robust CI/CD and proactive testing.

Qualifications

• Strong debugging skills and proficiency with native profiling tools.
• 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.
• Clear and effective communication with cross-functional teams.
• Experience writing and debugging UI automation tests.
• Familiarity with feature flagging and controlled rollout strategies.

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.

Skills

Debugging

Memory management

Async programming

API design

Unit testing

CI/CD

QA validation

Cross-functional comms

UI automation

Feature flags

Tools

Xcode

Instruments

Swift Package Manager

Job description

Knot seeks a Senior iOS Engineer to shape the architecture and reliability of our iOS SDK powering fintech experiences. You will work end-to-end from design to release, profiling performance, catching issues early, and drafting documentation for easy integration.

You will collaborate with product and engineering across the company, advocate for best practices, and help scale our mobile platform with robust CI/CD and proactive testing.