Mobile Application Engineer

Sequester; United States; Remote; USD 120,000 - 180,000; Full time

Job summary

Sequester is seeking a mobile engineer to deepen native capabilities for a privacy-first vault, bridging Swift/Kotlin with a shared Flutter codebase for secure media handling and OS-level security.

You will implement native modules, debug release and beta builds, optimize media capture and background uploads, and collaborate with security teams on keychain-keystore integrations and app attestation while supporting signing and distribution processes.

Qualifications

• Strong iOS and/or Android native development experience.
• Ability to work across the Flutter boundary when features require platform code.
• Understanding of mobile security APIs such as Keychain, Keystore, and App Attest.
• Ship discipline including feature flags, staged rollouts, and crash monitoring.

Responsibilities

• Build and maintain native modules in Swift and Kotlin for camera, keychain, and OS integrations.
• Debug platform-specific bugs in release builds and OS beta previews.
• Optimize media capture, thumbnail generation, and background upload on device.
• Collaborate with AppSec on secure storage and jailbreak or root detection policies.
• Support release engineering with signing, provisioning, and store submission fixes.

Skills

iOS/Android native development

Flutter integration

Mobile security

Crash monitoring

Release engineering

Tools

Swift

Kotlin

Keychain

Keystore

App Attest

Job description

Role overview

Help deepen the native mobile capabilities of a privacy-first encrypted vault for personal photos and videos, bridging Flutter and platform APIs where users expect OS-level security, notifications, and media performance. The work centers on the intersection of native code and a shared Flutter codebase for sensitive media handling.

Responsibilities

• Build and maintain native modules in Swift and Kotlin for camera, keychain, and OS integrations.
• Debug platform-specific bugs in release builds and OS beta previews.
• Optimize media capture, thumbnail generation, and background upload on device.
• Collaborate with AppSec on secure storage and jailbreak or root detection policies.
• Support release engineering with signing, provisioning, and store submission fixes.

Requirements

• Strong iOS and/or Android native development experience.
• Ability to work across the Flutter boundary when features require platform code.
• Understanding of mobile security APIs such as Keychain, Keystore, and App Attest.
• Ship discipline including feature flags, staged rollouts, and crash monitoring.

Benefits and work setup

Remote-friendly position with global hiring and an async-first collaboration model across time zones.