Senior iOS Developer- Real-Time Safety-Critical Application (US Only- no agencies)

Job Objective We are looking for a Senior iOS Developer to take end-to-end ownership of mobile features on a real-time, safety-critical public safety application built on AWS serverless infrastructure. This is not a typical CRUD app- the platform handles emergency calling, real-time location tracking, and WebSocket-based communication where reliability is non-negotiable. You will be working in an existing codebase with significant technical debt, including tightly coupled iOS and backend code built by separate teams. The role requires someone who can debug production concurrency issues, architect resilient networking layers, and confidently explain complex code changes to stakeholders who may push back. This is a hands-on engineering role. You must be comfortable inheriting someone else's code, diagnosing deeply embedded issues, and delivering under pressure with minimal oversight. Key Responsibilities iOS Development & Networking Architecture Own and improve the native Swift iOS application, including real-time features and background processing. Diagnose and resolve thread safety issues, race conditions, and concurrency bugs using GCD, Swift Concurrency (async/await), and structured concurrency patterns. Architect robust networking layers handling REST APIs, WebSocket connections (Starscream), offline sync, retry logic with exponential backoff, and background URL sessions. Design and implement location update pipelines that respect network conditions, battery life, server rate limits, and App Store background mode requirements. Build and maintain real-time calling features using Bandwidth (SOS/emergency calling) and WebRTC. WebSocket & Real-Time Communication Manage WebSocket reconnection lifecycle across app backgrounding, network handoffs (WiFi to cellular), token expiry, and server-side disconnects. Implement token-aware WebSocket messaging, including handling in-flight messages during authentication refresh cycles. Ensure persistent, battery-efficient real-time connections for safety-critical features. Authentication & Security Work with AWS Cognito for user authentication, token management, and session handling. Implement proactive token refresh strategies that coordinate across REST and WebSocket layers. Identify and remediate security issues in the existing authentication implementation. Backend Integration & Cross-Stack Debugging Trace and debug issues end-to-end from the iOS client through API Gateway, Lambda (Node.js), and Aurora PostgreSQL. Troubleshoot Salesforce synchronization, enrollment, and customer lifecycle workflows as they surface on the mobile client. Work closely with backend engineers to resolve tightly coupled dependencies between iOS and serverless backend code. Stakeholder Communication Deliver 2–3 hour technical presentations on code changes to client stakeholders. Perform root-cause analysis and explain findings clearly to both technical and non-technical audiences. Navigate client relationships where previous development decisions are being questioned. Required Qualifications 7+ years of native iOS development experience using Swift Deep expertise in Swift concurrency: thread safety, race conditions, GCD, async/await, structured concurrency Strong networking architecture experience: URLSession, background sessions, request queuing, deduplication, retry strategies, and offline handling Production experience with WebSocket implementations (Starscream or URLSessionWebSocketTask) Experience building or maintaining real-time calling features (WebRTC, Bandwidth, or similar) Experience integrating iOS applications with AWS backend services (Lambda, API Gateway, S3, Cognito) Ability to read and troubleshoot backend code written in Node.js Experience with PostgreSQL or Aurora PostgreSQL Proven track record of working in large, legacy codebases with significant technical debt Strong root-cause analysis skills and ability to debug complex production issues across mobile and backend layers Excellent communication skills- comfortable presenting technical changes to skeptical stakeholders

Preferred Qualifications

Experience with real-time public safety, emergency response, or mission-critical applications Experience with Bandwidth.com APIs for voice/SMS/emergency calling Familiarity with Salesforce integrations from a mobile client perspective Experience with agentic AI development tools (especially Claude) and willingness to adopt AI-assisted development workflows Experience with CoreLocation background modes, significant location monitoring, and App Store review considerations for background location usage AWS certifications or demonstrated AWS architecture knowledge Technology Stack - Native iOS (Swift) - Starscream (WebSocket) - Bandwidth (voice/emergency calling) - AWS Cognito (authentication) - AWS Lambda (Node.js 24) - API Gateway - Aurora PostgreSQL - S3 - Serverless Framework / SST - GitLab CI/CD What Success Looks Like Thread safety and race condition issues on the iOS side are resolved and the root causes are documented. Networking layer is stabilized with proper request management, retry logic, and WebSocket resilience. Emergency calling flow is reliable under all network conditions. Technical debt is systematically reduced with clean, maintainable code. Client stakeholders understand and trust the code changes being delivered. Solutions are well-documented and transferable to the broader engineering team. Candidates must be U.S.-based and authorized to work in the United States. Apply tot his job Apply To this Job