Sekai

Role Description We are looking for a Senior iOS Engineer to own Sekai’s iOS app and help us build a fast, polished, AI-native consumer experience. This role is for someone with strong iOS experience, good consumer product taste, and the ability to move quickly in a startup environment. You should keep up with the latest Apple platform updates, understand what great mobile apps feel like, and be excited to use AI to rethink how fast a small team can build. You will work closely with Product, Design, Backend, and Mobile engineers to improve the iOS app experience, ship new features, and help define our AI-native mobile development workflow. Responsibilities - Own and improve Sekai’s iOS app experience, quality, and release velocity - Build and ship consumer-facing iOS features with strong attention to speed, polish, and reliability - Bring modern iOS best practices and the latest Apple platform knowledge to the team - Work across native iOS, hybrid mobile, and web-based app experiences when needed - Partner closely with Product, Design, Backend, and Mobile engineers to move from idea to shipped product quickly - Use AI development tools to accelerate coding, debugging, refactoring, and product iteration Qualifications - Strong professional experience building and shipping iOS apps - Deep familiarity with Swift, iOS SDK, and modern iOS development practices - Experience working on consumer mobile apps with high standards for UX, performance, and reliability - Experience owning projects end-to-end in a startup, 0-to-1 product environment, or similarly fast-moving team - AI-native mindset: you actively use AI tools to build faster, explore better implementation paths, and improve engineering productivity - Strong product sense and willingness to work closely with design and product teams Nice to Have - Experience with social, entertainment, creator, gaming, UGC, or feed-based consumer products - Experience with React Native, Flutter, WebView, or other hybrid mobile architecture - Familiarity with Android, backend systems, or full-stack product development - Experience working on AI-native products or teams that heavily use AI in day-to-day development Benefits - Work with an AI-native team - Move fast and own meaningful problems - Flexibility to explore new ideas from an early stage

• Build and improve recommendation and search systems across feed, discovery, search, and content continuation surfaces. • Own retrieval and ranking systems, including candidate generation, embedding-based retrieval, two-tower models, ranking features, and online serving quality. • Design, launch, and analyze recommendation/search experiments end-to-end, then use the data to iterate quickly. • Improve recommendation quality for new users, new content, and fast-changing content pools. • Build user, content, creator, and session-level representations from behavioral signals. • Partner with product, data, and engineering teams to define metrics, run experiments, and ship measurable improvements to retention, engagement, and content distribution. • Build practical ML systems that can move from prototype to production quickly, with clear monitoring and evaluation. • Help shape the long-term ML architecture for AI-native content discovery.

• Lead technical execution across backend, frontend, mobile, AI, and data initiatives • Translate ambiguous product goals into clear technical plans, milestones, owners, and trade-offs • Dive deep into hard technical problems and help drive them to resolution • Partner with founders, product, design, and engineering on technical decisions • Coordinate cross-domain engineering work and remove execution blockers • Raise the bar for engineering quality, speed, reliability, and maintainability • Help define hiring needs, role requirements, interview criteria, and technical evaluation standards • Build internal AI workflows and foster an AI-native engineering culture

Role Description We are looking for a Senior Data Engineer to own the data foundation behind Sekai’s product, growth, and company decision-making. This is one of the most important infrastructure roles at Sekai. You will build the systems that help the company understand how users behave, how the product performs, and where we should invest next. This role sits at the intersection of: - Data engineering - Backend instrumentation - Product analytics - Business intelligence - AI-ready internal data tooling The ideal candidate is not just a pipeline builder — they are a product-minded data owner who can turn ambiguous consumer product questions into scalable, trusted data systems. You will work closely with Product, Engineering, Growth, and Leadership, with hands-on ownership across: - BigQuery - PostHog - Amplitude Qualifications - 5+ years of professional experience in data engineering, data platform engineering, or a closely related role. - Strong hands-on experience with SQL, Python, and large-scale analytical data systems. - Deep experience with BigQuery, including warehouse design, query optimization, and cost-aware data modeling. - Experience working with product analytics tools such as PostHog, Amplitude, or similar platforms. - Strong understanding of consumer app analytics, including funnels, retention, cohorts, activation, engagement, and user journeys. - Ability to understand business and product needs, then translate them into scalable data architecture. - Comfortable working with backend engineers on tracking, data contracts, APIs, logs, and production data flows. - High ownership mindset; able to operate independently in a fast-moving startup environment. Requirements - Experience as an early data hire or primary owner of a startup data platform. - Experience building or rebuilding a data warehouse from 0 to 1. - Background in consumer apps, social products, UGC platforms, creator tools, gaming, or mobile-first products. - Backend engineering experience or strong familiarity with backend systems. - Experience building AI-ready data workflows, internal data tools, or governed self-serve analytics systems. - Strong side projects, open-source work, or independently built data products. Benefits - Top-tier salary in the market + competitive equity - Full health insurance - Remote-first team

Role Description We are looking for a Senior Android Engineer to build the native Android foundation for Sekai’s mobile product. This is an Android-first role focused on the core app shell, native platform architecture, product quality, release reliability, and hybrid integration with React Native, Flutter, and web-based experiences. The right person has shipped real consumer Android apps, understands the Android ecosystem deeply, and can make pragmatic architecture decisions in a fast-moving startup environment. You should be comfortable working close to the OS while partnering closely with Product, Design, Backend, and Mobile teams to build a fast, polished, mobile-first consumer experience. Responsibilities - Build and own Sekai’s native Android foundation using Kotlin, Android SDK, and modern Android architecture - Design and improve the Android app shell, navigation, lifecycle handling, session management, permissions, push notifications, deeplinks, and release workflows - Create clean integration points for product modules built in native Android, React Native, Flutter, or WebView - Partner with Product, Design, Backend, and Mobile engineers to ship high-quality consumer mobile experiences - Improve Android app reliability, responsiveness, maintainability, and production quality across real-world devices - Build observability and debugging workflows for crashes, app health, release quality, and user-impacting issues - Define engineering patterns for native modules, cross-stack communication, hybrid screen ownership, testing, CI/CD, and rollout - Use modern AI development tools to move faster while maintaining strong engineering quality Qualifications - 5+ years of professional Android engineering experience - Strong hands-on experience with Kotlin, Android SDK, and production Android app development - Experience building or owning major parts of a consumer-facing Android app - Strong understanding of Android architecture, app lifecycle, navigation, concurrency, networking, persistence, dependency management, and modularization - Experience building high-quality mobile UI using Jetpack Compose and/or the traditional Android View system - Strong product sense and care for mobile user experience, polish, responsiveness, and reliability - Ability to make independent architecture decisions and clearly explain technical tradeoffs - Strong ownership mindset and ability to drive work end-to-end in a fast-paced environment - Comfortable collaborating closely with Product, Design, Backend, Mobile, and Growth teams Preferred Qualifications - Experience leading or helping lead a team to build a mobile app from 0 to 1 - Experience working in a startup or high-growth consumer product environment - Experience with React Native, including native modules, bridges, or hybrid mobile architecture - Experience integrating Flutter or WebView-based modules into native Android apps - Experience with Android performance profiling, startup optimization, memory management, UI responsiveness, crash reduction, or app health monitoring - Experience with mobile observability and analytics tools such as Firebase Crashlytics, Sentry, Datadog, Amplitude, GA4, or similar tools - Experience with feed-based, social, entertainment, creator, gaming, UGC, marketplace, or other high-engagement consumer products - Experience with Gradle, CI/CD, staged rollouts, Play Console, app signing, and release automation - Familiarity with iOS, TypeScript, React Native, Flutter, or web-based interactive content is a plus - Experience using AI coding tools such as Cursor, Claude Code, Codex, or GitHub Copilot Benefits - Top-tier salary in the market + competitive equity - Full health insurance - Remote-first team

Role Description We are looking for an AI-native Mobile Engineer to help build the next generation of Sekai’s mobile experience. This role is focused primarily on React Native development. You will work on core mobile product surfaces, improve performance and quality, and help us build a fast, polished, mobile-first consumer app. You should care deeply about user experience, move fast, and be comfortable using AI tools as part of your daily engineering workflow. The right person is product-minded, strong in ownership, and excited to work across product, design, and engineering in a fast-moving startup environment. Experience with Android Native development is a strong plus, especially if you have worked on mobile performance, startup speed, scrolling performance, memory usage, crash rate, ANR, or low-end Android device optimization. Responsibilities - Build and ship React Native mobile features end-to-end across Sekai’s core consumer experience - Work on high-impact product surfaces such as feed, discovery, creation, play experience, sharing, onboarding, retention, and user engagement - Improve mobile app performance, stability, responsiveness, and overall product quality - Debug and fix production issues quickly, with strong judgment around user impact and prioritization - Collaborate closely with Product, Design, Backend, and Growth to turn product ideas into shipped mobile experiences - Integrate React / web-based interactive content into the mobile app experience where needed - Use analytics, logs, crash reports, and user feedback to identify and solve mobile product issues - Use AI aggressively in day-to-day development, debugging, prototyping, testing, and iteration - Help shape Sekai’s long-term mobile architecture as the product scales Qualifications - 3+ years of professional software engineering experience, ideally with mobile or consumer-facing products - Strong hands-on experience with React Native - Strong proficiency with TypeScript / JavaScript - Experience shipping production mobile apps on iOS and/or Android - Good understanding of mobile app architecture, navigation, state management, API integration, release cycles, and app store deployment - Strong product sense and care for user experience, especially on mobile - Able to debug issues independently and move quickly from problem discovery to shipped fix - Highly AI-native, with strong familiarity using modern AI coding tools such as Cursor, Claude Code, Codex, or similar tools - Strong ownership mindset and ability to drive work end-to-end - Comfortable working in a fast-paced startup environment with ambiguity Preferred Qualifications - Experience with Android Native development, especially Kotlin, Java, Android SDK, or Jetpack Compose - Experience optimizing Android performance, including startup time, scrolling performance, memory usage, crash rate, ANR, and low-end Android device performance - Experience building or maintaining hybrid mobile architectures, including React Native + native modules, WebView integration, or native bridges - Experience with Flutter, especially migrating from Flutter to React Native or maintaining apps across multiple mobile stacks - Experience with mobile-first consumer products, social products, UGC platforms, gaming, entertainment, creator tools, or feed-based apps - Experience with mobile analytics, crash reporting, and performance tools such as Firebase, Amplitude, GA4, Sentry, Datadog, Android Studio Profiler, or similar tools - Experience at an early-stage startup or high-growth consumer company - Strong side projects, open-source contributions, or independently shipped apps are a plus Benefits - Top-tier salary in the market + competitive equity - Full health insurance - Remote-first team

• Own some key areas of Sekai’s consumer product experience, including creation, discovery, feed experience, sharing, retention, and creator/player engagement • Turn ambiguous user problems into clear product hypotheses, priorities, requirements, and execution plans • Analyze user behavior, funnels, retention, engagement, feedback, and product metrics to identify opportunities • Define success metrics for product launches and experiments • Work closely with engineering, design, data, growth, and operations to ship quickly • Use AI tools to accelerate research, product thinking, data analysis, prototyping, documentation, QA, and execution • Communicate clearly on priorities, blockers, trade-offs, decisions, and next steps

• Own end-to-end design across key product surfaces on mobile and web • Drive UX for major product flows and make clear product experience decisions • Improve the overall quality, clarity, and polish of the product • Define and evolve product DNA, visual language, interaction patterns, and design systems • Work closely with founders, product, and engineering to shape and ship new experiences • Use modern AI and design tools to explore, prototype, and iterate quickly

• Build and ship product features end-to-end, with most of the role focused on new feature development • Debug and fix production issues quickly, with strong judgment around user impact and prioritization • Partner closely with Product to turn ideas into shipped experiences and contribute to product direction and user experience decisions • Use AI aggressively in day-to-day development, debugging, prototyping, and iteration • Move quickly across the stack to improve product quality, speed, and usability • Help the team ship faster through strong execution, ownership, and product-minded engineering

• Designing and owning our agent harness layer • Building long-horizon agentic workflows with maximal autonomy • Developing robust evaluation and quality loops, including eval harnesses, regression testing, and failure taxonomies • Designing model strategy: routing, benchmarking, reliability, and cost/latency optimization • Creating debuggable agent systems with tracing, metrics, alerts, and observability • Researching novel approaches and shipping them to production