Senior Mobile Engineer (Swift and/or Kotlin)

• At least 6 years of native mobile development, including at least 3 years in Swift (iOS) and/or Kotlin (Android).
• At least two apps shipped to production and maintained through multiple releases.
• Deep knowledge of one platform: for iOS, SwiftUI, UIKit, Swift Concurrency or Combine, and the Xcode toolchain; for Android, Jetpack Compose, Kotlin Coroutines and Flow, Android Jetpack, and Gradle. Working understanding of the other platform.
• Hands-on experience with mobile security in regulated environments, including OAuth2 / OIDC, strong customer authentication flows, secure storage, certificate pinning, OWASP MASVS, and resolving pen-test findings.
• Solid testing and CI/CD practice, including XCTest or JUnit, UI and snapshot tests, automated pipelines, code signing, store submission and release management.
• Ability to own architecture decisions and safely refactor large legacy codebases, with measurable improvements in build time, crash rate or release cadence.
• Experience designing or integrating a server-driven UI framework, including component schemas, a client renderer, schema versioning and A/B-tested layouts; understanding of where SDUI is suitable and its limitations, including offline use, performance and accessibility.
• Daily use of coding agents and copilots; understanding their failure modes and reviewing AI-generated code to the same standard as other code.
• Experience with REST and GraphQL API integration, OpenAPI contracts, and working with backend teams on API design.
• Experience delivering apps in banking, insurance, fintech or healthcare, including PII handling and regulatory constraints such as PSD2 / SCA and GDPR.
• Clear communication with non-engineers, explaining trade-offs to a product owner and estimating honestly.
• Full professional fluency in Polish and English.

Nice to have:

• Mobile payments integration with Apple Pay, Google Pay or BLIK.
• Accessibility auditing experience with VoiceOver or TalkBack.
• Tech lead or team lead experience on a client-facing engagement.
• Experience building team AI tooling, such as custom agents, MCP servers, or codebase-specific skills and prompts.
• Experience shipping an SDUI-based app at scale or contributing to an open-source SDUI framework.

• Design and build native apps in Swift (SwiftUI, UIKit) and/or Kotlin (Jetpack Compose), including new features, legacy code modernisation and justified rewrites.
• Own platform architecture, including modularisation, MVVM, Clean Architecture, TCA, dependency injection, offline-first approaches and data-sync strategies.
• Build and evolve server-driven UI (SDUI): design component schemas with backend teams using JSON or Protobuf, own client-side rendering, and manage schema versioning, backward compatibility and fallbacks.
• Use coding agents and copilots such as Claude Code, Cursor and GitHub Copilot for implementation, refactoring, test generation and code review; verify their output and help the team adopt this practice.
• Integrate backend services using REST, GraphQL and gRPC, and secure apps with OAuth2 / OIDC, biometrics, secure storage (Keychain, Keystore), certificate pinning, root and jailbreak detection, and OWASP MASVS.
• Set and enforce engineering standards covering code review, unit, UI and snapshot tests, CI/CD with Fastlane, GitHub Actions, Azure DevOps or Bitrise, signing, and App Store and Google Play release management with phased rollouts.
• Build observability and product quality practices covering crash reporting, analytics, feature flags, performance and startup-time budgets.
• Deliver accessibility to WCAG 2.2 / EN 301 549 standards and localisation for regulated clients.
• Work with client product owners, designers, backend engineers and QA; estimate, plan and demo work to stakeholders.
• Mentor mid-level engineers, raise standards across the mobile practice, and support proposals and pre-sales demos.