Principal Engineer, Mobile

Slate is looking for a Principal Engineer to anchor the technical depth of the Mobile Experience pod. This is the senior-most individual contributor on the mobile team - the person who shapes architecture, sets the engineering quality bar, and personally closes the hardest technical gaps standing between our current build and a November GA launch. The Slate mobile app covers a wide technical surface: a React Native / TypeScript product layer, a custom native module for vehicle communication, a dedicated mobile backend-for-frontend, platform-level security and encryption, and integrations spanning EV charging, service scheduling, account management, and over-the-air update delivery. You need to be equally comfortable driving complex product features in React Native and reasoning through low-level native module behavior, and you should be able to step into backend service work when mobile product needs require it. You must be able to thrive and succeed in a fast-paced startup environment where your contributions have a direct impact on the company's direction and success and should not be hindered by ambiguity or competing priorities. What You Get to Do Vehicle Communication and Native Module Engineering Serve as the architectural owner of the C++ Turbo Module that bridges the React Native JS layer to the vehicle Secure Gateway Module over USB/DTLS - setting direction, leading design decisions, and being the escalation point for the hardest debugging and performance issues in the native layer. Own the TypeScript/C++ boundary defined by the TurboModule Codegen spec - vehicle data polling, UDS diagnostic requests, CAN bus messaging, OTA update management, DTC operations, and security access - and ensure the team is building to that contract correctly. Provide architectural guidance on CAN decoder design and the shared CAN message definitions package; review and approve significant changes to the vehicle communication data model. Drive the DTLS session lifecycle architecture: certificate issuance, BFF-mediated vehicle security endpoints, and cryptographic operations within the native layer. Lead the evaluation and outcome decision on protobuf-based dynamic DID mapping to align vehicle communication with the source-of-truth data model. Apply and reinforce the Definition of Done for vehicle communication PRs in code reviews; serve as the technical bar for what constitutes a well-tested, merge-ready change in the native communication layer. Mobile Application Architecture and Product Features Own the overall layered application architecture - from Presentation through Native Modules and Data Persistence - making binding calls on structure, patterns, and technology decisions as the app scales toward GA and beyond. Drive architecture and implementation across active epics: EV Charging, Service Scheduling, Vehicle Settings, and Key Management / Plugged-In flows; jump into hands-on implementation where the team needs technical leadership or the problem requires it. Set the standard for server state management patterns across the app - caching, synchronization, optimistic updates, and stale-while-revalidate behavior - and ensure consistent application across charging, vehicle data, and scheduling endpoints. Own the encrypted local storage architecture and its per-VIN partitioning scheme; provide direction on schema validation hardening across all storage reads and writes. Lead warm-start lifecycle hygiene: diagnose and resolve lifecycle risks across screens and establish preventative patterns the team applies going forward. Provide architectural direction on embedded WebView integrations - Account Management, Finance, E-Commerce - including secure session-token passing and native-to-web message bridge contracts. Own the push notification architecture end-to-end: backend integration approach, client-side token management and permission flow, deep-link routing strategy, and encryption requirements. Backend-for-Frontend and Service Integration Provide technical direction on the mobile BFF - jump in to extend or debug service endpoints for charging, service scheduling, vehicle security, and auth flows when mobile product needs it. Own the mobile API client architecture: JWT refresh strategy, API key gating, and version-safe endpoint evolution that accommodates multiple installed app versions in the wild. Drive charging API ownership resolution and close any gap between mobile BFF needs and backend service contracts. Provide technical oversight on RepairPal BFF integration, ensuring the service scheduling flow is robust to backend latency, partial failures, and slot availability edge cases. Observability, Quality, and Reliability Set the observability strategy for the mobile app: Datadog RUM configuration, structured logging architecture, and production crash reporting standards. Be the escalation point for the most severe production issue categories - native-layer crashes, DTLS session drops, and vehicle state failures - driving diagnosis and resolution across whatever layer the problem lives in. Partner with the QAM on testability: ensure new features and architectural changes are designed to be testable, provide the technical context the QA team needs to build effective test coverage, and unblock QA on gray-box testing at the vehicle communication layer. Lead performance profiling efforts using Datadog RUM: identify root causes of long JS tasks exceeding the >100ms threshold, set response time targets for user-initiated vehicle interactions, and drive the team toward those benchmarks. Build, Release, and OTA Infrastructure Own the overall build and release architecture for iOS and Android: EAS Build pipeline, provisioning lifecycle, distribution strategy, and production submission process. Set the OTA update delivery strategy: define update channels, rollout policies, and rollback procedures; make the native vs. OTA boundary call and communicate it to the team and stakeholders. Own App Store and Google Play certification readiness; resolve platform compliance issues on both iOS and Android ahead of GA submission. Technical Leadership and Cross-Team Collaboration Set technical direction for the MOB pod: produce Architecture Decision Records, lead design reviews, and surface blockers to the Engineering Lead before they become timeline risks. Mentor SDE IIs and SDE IIIs; conduct PR reviews with clear, actionable feedback grounded in established architecture and patterns. Represent mobile engineering in cross-pod and cross-discipline forums: Digital LT technical discussions, vendor security reviews, and vehicle interface definition sessions with Embedded and Vehicle Software. Actively adopt and demonstrate AI-assisted development workflows; serve as a visible example of engineering capability across the Digital org. What You Bring to the Team Required • Bachelor of Science in Computer Science, Computer Engineering, Electrical Engineering, or equivalent work experience. • 10+ years of professional software engineering experience with at least 4 years in mobile application development (iOS, Android, or React Native). • Deep familiarity with C++ native module architecture in a React Native context: sufficient to lead design decisions, diagnose native-layer crashes, and provide meaningful technical direction to engineers working in the layer - without necessarily being the primary author. • Deep React Native expertise: Turbo Modules, Expo ecosystem (EAS Build, EAS Update, Expo Router), TypeScript, and state management patterns. • Demonstrated ability to build or maintain backend services: REST API design, authentication middleware, JWT lifecycle, and integration with third-party services. • Experience with serial or embedded communication protocols: CAN bus, UDS diagnostics, DID-based data polling, or DTLS/TLS in constrained hardware environments. • Fluency with mobile security patterns: hardware-backed key management, encrypted local storage, certificate-based device authentication, and secure WebView session injection. • Strong CI/CD and release engineering skills: multi-environment build pipelines, OTA update strategy, and App Store / Google Play submission experience. • Experience with mobile observability tooling: setting up instrumentation, diagnosing production crashes, and running performance profiling. Strongly Preferred • Automotive software experience: secure gateway architectures, vehicle certificate issuance flows, or embedded cryptography. • Experience integrating EV charging networks or fleet telematics platforms. • Familiarity with Protocol Buffers or dynamic vehicle data configuration mapping. • Prior work scaling a mobile product from pre-GA to GA launch with hard date constraints. Salary Range The compensation for this position is the range Slate reasonably and in good faith expects to pay for the position taking into account the wide variety of factors that are considered in making compensation decisions, including job-related knowledge; skillset; experience, education and training; certifications; work location; and other relevant business and organizational factors. Base Pay Range (Annual) $202,610.00 - $337,684.00 USD Additional Compensation and Benefits: Slate offers a wide range of competitive benefits, including medical, dental, vision, life insurance, disability insurance, vacation, and 401k. The successful candidate may also be eligible to participate in the equity program and/or a discretionary annual incentive program, subject to the rules governing such programs.