Senior Full Stack iOS Engineer

ZipStaff Inc.; Washington (District of Columbia); Sur place; USD 140 000 - 190 000; Plein temps

Avantages offerts par ce poste

Health Insurance

Dental Insurance

Vision Insurance

401(k) + 401(k) matching

Paid time off

Referral Program

Résumé du poste

ZipStaff Inc. is seeking a Senior Full Stack iOS Engineer to design, build, and maintain mission-critical frontline mobile apps and the supporting AWS cloud services for a transportation leader.

On-site in Washington, DC, you will drive offline-first architectures, real-time tracking, and secure integrations within SAFe. You will own iOS development with Swift/Objective-C, implement peer-to-peer sync, Bluetooth integrations, and BFF REST APIs on AWS, collaborating with backend and platform teams

Qualifications

• Proven track record delivering enterprise iOS apps in production with Swift and Objective-C.
• Experience designing offline-first mobile systems with local persistence and sync.
• Backend integration experience with AWS services such as API Gateway, Lambda, ECS, Cognito.
• Experience integrating external hardware like barcode scanners or Bluetooth devices.

Responsabilités

• Architect, develop, and maintain high-performance native iOS apps using Swift and Objective-C.
• Design offline-first data architectures with local queues and peer-to-peer sync.
• Deliver front-line workflows including barcode scanning, manifest management, and check-in states.
• Integrate mobile clients with AWS REST APIs using OAuth/OIDC and secure storage.
• Build reusable UI components, feature flags, and dynamic forms for iPhone and iPad.
• Instrument apps with Dynatrace RUM and ensure crash resilience and privacy safeguards.
• Collaborate with backend teams on API idempotency and data schemas in SAFe.
• Participate in PI planning and capacity planning for Washington, DC onsite.

Connaissances

Swift

Objective-C

Offline-first design

AWS backend integration

Peer-to-peer synchronization

Bluetooth/BLE

SAFe agile

iOS performance

Dynatrace RUM

Outils

Ditto

Infinite PeerConnect

Dynatrace

Description du poste

Job Title: Senior Full Stack iOS Engineer (AWS / Mobile-First)

Location: Washington, DC (On-site)

Employment Type: Contract (W2 through ZipStaff — No C2C or 1099)

About the Opportunity

ZipStaff is seeking a Senior Full Stack iOS Engineer to design, build, and maintain mission-critical, native frontline mobile applications and the supporting AWS cloud services for a leading transportation organization.

In this role, you will lead the architecture of high-availability, offline-first passenger and employee operations, enabling reliable ticket scanning, real-time manifest tracking, peer-to-peer data synchronization, and secure backend integrations used daily by onboard conductors and station personnel. Working within an established Scaled Agile Framework (SAFe) environment, you will drive self-organized iteration planning, collaborate on resilient cloud/mobile contracts, and directly deliver seamless digital workflows where zero-downtime and data integrity are non-negotiable. This is an on-site role in Washington, DC.

What You’ll Do

• Architect, develop, and maintain high-performance native iOS applications utilizing Swift, applicable Objective-C, and modern concurrency models.
• Build robust, offline-first data architectures featuring local transactional queues, conflict resolution, reconnection/replay logic, and peer-to-peer sync mechanisms (e.g., Ditto, Infinite PeerConnect).
• Deliver end-to-end frontline workflows, including barcode/ticket scanning, passenger manifest management, check-in/lift states, and peripheral device integrations via Bluetooth.
• Design and integrate mobile clients with Backend-for-Frontend (BFF) REST APIs on AWS, leveraging OAuth/OIDC authentication, secure device storage, and request correlation.
• Implement reusable, configuration-driven UI components, feature flags, dynamic forms, and role-based workflows across supported iPhone and iPad devices.
• Instrument applications with Dynatrace mobile RUM, crash symbolization, privacy safeguards, and real-time performance telemetry.
• Partner with backend and platform teams on contract testing, API idempotency, and unified mobile-to-cloud data schemas.
• Champion Agile self-management within a SAFe structure—actively participating in capacity planning, iteration commitments, and onsite Program Increment (PI) planning events in Washington, DC.

Required Qualifications

• Proven track record building enterprise native iOS applications in production using Swift and Objective-C.
• Hands-on experience architecting offline-first mobile systems, Core Data persistence, local queueing, and peer-to-peer or edge synchronization frameworks.
• Practical backend experience designing or integrating AWS services, including API Gateway, Lambda, ECS Fargate, and Cognito/Entra ID (or Spring Boot microservices).
• Direct experience integrating external hardware peripherals (barcode scanners, sleds, or Bluetooth/BLE devices).
• Demonstrated knowledge of mobile performance optimization, thread safety, crash resilience, VoiceOver accessibility, and mobile monitoring tools like Dynatrace RUM.
• Familiarity with high-availability operational environments such as transportation, ticketing, reservations, or point-of-sale systems.
• Working knowledge of or formal training in SAFe (Scaled Agile Framework), with the ability to lead sprint commitments and capacity planning autonomously.
• Must be based within commuting distance of Washington, DC, available to attend key milestone ceremonies (such as PI Planning) onsite, and comfortable maintaining a camera-on collaborative presence during hybrid team sessions.
• Ability to work on-site in Washington, DC.

Preferred Qualifications

• Prior experience delivering offline-first mobile solutions for transportation, rail, or frontline operational environments.
• Hands-on experience with peer-to-peer synchronization frameworks and conflict resolution in production mobile apps.
• Strong background integrating mobile clients with AWS-based Backend-for-Frontend architectures.
• Experience instrumenting mobile applications with Dynatrace or similar real-user monitoring tools.

Benefits

• Health Insurance.
• Dental Insurance.
• Vision Insurance.
• 401(k) + 401(k) matching.
• Paid time off.
• Referral Program.

About ZipStaff

ZipStaff partners with leading organizations to connect skilled technology professionals with high-impact contract opportunities. We focus on quality matches, clear communication, and long-term success for candidates and clients.