Engineering expertise
These pages make the technical breadth behind my case studies explicit: mobile, web, APIs, databases, authentication, payments, voice and LLM integrations, cloud/release workflows, and search/distribution. Each area connects back to products that provide evidence instead of relying on a keyword list alone.
Mobile engineering
React Native and Expo engineering for production iOS and Android apps, including authentication, audio, payments, location, local persistence, testing, EAS builds, OTA updates, and App Store / Play Store release work.
Web engineering
Next.js and React engineering for workflow-heavy applications, operational dashboards, public product websites, authenticated workspaces, responsive interfaces, and search-oriented product surfaces.
Backend & data
Python, FastAPI, SQLAlchemy, Alembic, PostgreSQL, REST API, authentication, callbacks, and transactional backend engineering for real product workflows.
APIs & integrations
API engineering across FastAPI REST services, GraphQL, webhooks, callbacks, payment providers, authentication, cloud services, and third-party product integrations.
Databases & data modeling
Relational and application data modeling with PostgreSQL, SQL, SQLAlchemy, Alembic, SQLite, graph databases, local persistence, caching patterns, migrations, and transactional business state.
Voice AI & LLM products
Voice and audio application engineering across speech-to-text, Whisper, ElevenLabs Scribe v2, speaker diarization, word timestamps, acoustic emotion analysis, Gemini structured reasoning, emotion2vec, Modal model serving, audio diagnostics, LLM reasoning, and voice-product workflows.
Authentication & application security
Practical application security across OAuth, Google/Apple sign-in, access and refresh tokens, SecureStore, biometrics, password hashing, role-based access, tenant/facility isolation, KYC/KYB, and sensitive workflow controls.
Payments, FinTech & SaaS
Payment and SaaS engineering across M-Pesa/Daraja, invoice reconciliation, ledgers, callbacks, receipts, subscriptions, RevenueCat, KYC/KYB, and financial workflow design.
Testing & quality engineering
Automated testing across Playwright web E2E, Maestro mobile E2E, pytest backend/API suites, Jest and Node.js tests, React Native testing, integration tests, regression coverage, linting, type checks, and static analysis.
CI/CD & app release
Practical CI/CD and release work with Git/GitHub branches and merges, automated test gates, Vercel, Expo EAS Build, TestFlight, App Store Connect, Google Play Console, closed testing, production builds, and OTA updates.
Technical SEO & search growth
Technical SEO and intent marketing across Next.js metadata, canonical URLs, structured data, XML sitemaps, robots directives, internal linking, Google Search Console, Bing Webmaster Tools, Screaming Frog, and Google Ads search campaigns.