Mid Backend Developer Jobs in Seattle, WA (NOW HIRING)

Job Summary:
Level is a learning technology company dedicated to helping students build real academic and life skills with confidence and joy. As a Senior Full-Stack Mobile Engineer on the Platform team, you will own end-to-end slices of Level's mobile experience, designing and implementing mobile features and backend services that enhance student engagement and experience. Your work will directly impact how quickly the engineering organization can ship mobile-enabled features.
Responsibilities:
• Design, build, and ship user-facing mobile features end-to-end — native client work on iOS and/or Android, plus the backend services and APIs that power them.
• Implement clean, readable, testable code that follows platform best practices on the client and Level's service conventions on the backend.
• Take responsibility for features from initial design through release and ongoing maintenance.
• Evolve module boundaries, navigation, state management, and offline behavior in the mobile clients.
• Make sharp build-vs-share decisions between fully native code and cross-platform approaches (Kotlin Multiplatform, shared protobuf contracts, WebViews) based on real product and engineering trade-offs.
• Design and operate backend services (Kotlin or Java on the JVM, or TypeScript) that back the mobile experience — identity, content, sync, telemetry.
• Define and own reliability targets (SLOs/SLIs) for the services you own; implement structured logging, metrics, and tracing.
• Profile, debug, and optimize performance on device — startup, memory, battery, network — and on the backend — latency, throughput, cost.
• Apply mobile security fundamentals: secure storage (Keychain / Keystore), biometric auth, transport security, and handling of sensitive user data, with particular care for student data and K-12 privacy requirements.
• Participate in incident response and post-mortems for what you own.
• Partner with product, design, web/backend engineers, infrastructure, and QA to translate product requirements into pragmatic mobile + backend designs and ship them iteratively.
• Participate actively in planning, technical discussions, code reviews, and release processes — contributing practical input on feasibility, trade-offs, and implementation details.
• Own the release pipeline for the platforms you ship on (App Store Connect / TestFlight or Play Console), including staged rollouts and production monitoring.
• Ensure high standards of performance, stability, and test coverage on the mobile codebase and the services behind it; partner with our DevProd lead on mobile test strategy in CI.
• Actively contribute to improving app architecture, technical foundations, and developer experience.
• Identify and address technical debt, production issues, and scalability concerns — leave the code better than you found it.
• Mentor mid-level and associate engineers through pairing, code reviews, and technical guidance; help shape the conventions the rest of the team adopts.
Qualifications:
Required:
• 5+ years of professional software engineering experience, including 3+ years of production native mobile development on at least one platform (Swift / SwiftUI / UIKit on iOS, or Kotlin / Jetpack Compose on Android).
• At least one shipped mobile app at meaningful scale that you contributed to end-to-end (App Store or Play Store releases, production telemetry, real users).
• Solid working knowledge of the other mobile platform (iOS or Android, whichever isn't your primary) — enough to read, review, and contribute to code there.
• Strong backend proficiency in Kotlin or Java on the JVM (Kotlin is Level's primary backend language) or TypeScript for shared platform libraries and tooling; demonstrated experience designing and operating long-lived backend services. (Kotlin shared between Android and backend is a clear plus.)
• Strong understanding of mobile application architecture and common patterns — MVVM, MVI, Clean Architecture, and modularization — and the trade-offs between them.
• Deep understanding of mobile fundamentals — concurrency (async/await, coroutines, Combine, Flow), lifecycle management, memory and battery considerations, networking, persistence, offline-first behavior, and accessibility (VoiceOver / TalkBack, Dynamic Type / large fonts).
• Solid grasp of HTTP, REST, and gRPC + protobuf — Level's primary service-contract framework.
• Working knowledge of AWS, containers (Docker / Kubernetes), and CI/CD pipelines as a consumer. Familiarity with Linkerd, ArgoCD, Terraform is a plus.
• Knowledge of mobile security fundamentals — secure key/credential storage, biometric authentication, transport security — and experience handling sensitive user data in production.
• Experience working with Git, CI/CD pipelines (GitHub Actions), and collaborative code-review processes.
• Strong testing discipline — unit, integration, UI / instrumentation — and a track record of partnering with QA/DevProd to ship reliably.
• Ownership mindset, strong problem-solving skills, and clear written and verbal communication with cross-functional teams.
Preferred:
• Direct production experience with both iOS and Android, not just literacy.
• Experience with cross-platform mobile — Kotlin Multiplatform, React Native, Flutter — and a clear point of view on when it's the right tool.
• Familiarity with App Store and Play Console review processes, privacy manifests, Data Safety declarations, and family-friendly policy requirements.
• Familiarity with OpenTelemetry and modern observability stacks (SigNoz — Level's stack — Grafana); mobile crash reporting (Sentry / Crashlytics).
• Background in EdTech, K-12, or other domains with strong privacy and accessibility requirements (FERPA, COPPA, WCAG).
• Exposure to Backstage, internal developer platforms, or other developer productivity surfaces.
• Contributions to relevant open-source projects (mobile frameworks, cross-platform libraries).
Company:
Level is a learning technology that blends proven curriculum with interactive design to aligned practice tools for students, teachers. Founded in , the company is headquartered in Austin, TX, US, , with a team of 51-200 employees. The company is currently Growth Stage.