- Built the intake agent: roof photos in, damage assessment and a draft claim out.
- Shipped real-time AI chat on Claude and OpenAI with Python Lambdas on AWS SAM, plus ElevenLabs voice input that cut manual data entry by 60%.
- Led the V2 redesign: 20+ screens to shadcn/ui and Tailwind. Core Web Vitals up 45%, bundle down 35%.
12
years shipping production software
20+
apps in production
50K+
active users on apps I shipped
+35%
signup conversion at Paiv
Built for Paiv · Bridgestone · Bestway · AF Blakemore · Sugro · DroneAdair · UltiStay · Scoutedby
Selected work 05 projects
Motion studies rebuilt from the products I worked on. Client UIs stay private.
DroneAdair
Operations platform for commercial drone teams: flight logs, inspection reports, FAA compliance and computer-vision defect detection.
- Bootstrapped from zero as front-end lead.
- CI/CD that took Valari releases from every 2 weeks to every 2 days.
UltiStay
A rental marketplace in the Airbnb mould, on web and mobile.
- Took it from first architecture decisions to production release.
- One of 5+ products I led at Valari, alongside KilterRewards and rTurn.
UK wholesale
Trade ordering for Bestway, AF Blakemore and Sugro, used by thousands of independent retailers.
- Built 8 production apps across web and mobile.
- Shipped 4 to the App Store and Google Play, with 50K+ active users.
Bridgestone AG Tyres
Agricultural tyre pressure app for field technicians in the UK.
- Built and shipped it to the App Store and Google Play.
What you get 04
01
AI in production
Streaming LLM chat, RAG, voice and agents with tool use, running for paying customers on AWS. I care about evals and latency as much as the prompt.
02
The whole stack, one owner
React and React Native in front, Node, Python and GraphQL behind, AWS or GCP underneath. I can take a feature from Figma to the App Store.
03
A lead who still writes code
Led the Philippine team at Paiv through 2 major releases. Mentored 4+ engineers there and 4 at Valari through reviews and pairing.
04
Remote by default
Shipping with UK teams since 2018 and US teams since 2021. Working in UTC+8 and used to overlapping with US and UK hours.
Experience 2014 to now
2023 to nowSenior Fullstack EngineerPaiv (formerly GoGamify) · Remote, US
- Led the Philippine engineering team through 2 major platform releases; mentored 4+ developers.
- Built the roofing inspection and claims platform (reports, damage estimates, carrier submission) across iOS, Android and web.
- Shipped real-time AI chat on Claude and OpenAI with Python Lambdas and AWS SAM; RAG and agentic responses in production.
- Integrated ElevenLabs speech-to-text and text-to-speech, cutting manual data entry by 60%.
- Self-serve onboarding with Stripe billing, OTP auth, Meta Pixel and SMS automation: signup conversion up 35%.
- Cut load times 40% with caching, code splitting and GraphQL query work; V2 redesign lifted Core Web Vitals 45%.
2021 to 2022Front-End LeadValari Solutions · Minnesota, US
- Led the front end of 5+ web and mobile products from concept to production: DroneAdair, UltiStay, KilterRewards and rTurn.
- Built CI/CD and deployment automation that cut the release cycle from 2 weeks to 2 days.
- Mentored 4 developers through code review and pairing; wrote backend services in NestJS, Django and FastAPI.
2018 to 2021Fullstack EngineerRNF Digital / B2BStore · Leamington Spa, UK
- Built and maintained 8 production apps for UK wholesale clients including Bestway, AF Blakemore and Sugro.
- Shipped 4 mobile apps to the App Store and Google Play, including Bridgestone AG Tyres, with 50K+ active users.
- Set the Redux and MobX state patterns used across the company.
2017 to 2018Senior Fullstack Engineer, FE LeadScoutedby · Remote
- Led the school, student, admin and quiz platforms; ran code reviews and delivery.
- Migrated from MeteorJS to React, Node and GraphQL: 3x faster app, 10x faster feature work.
- Mentored junior developers and 2 interns.
2016Web Application DeveloperVeuta · Remote
- Built every front-end feature of an automated social messaging platform, including sentiment analysis and engagement workflows.
2014 to 2016Freelance DeveloperMesh Motion, MobileAds, Cynder
- Fleet management, responsive ad sites, prototypes and a team collaboration platform.
Stack 06 areas
- AI
- Claude · OpenAI · AWS Bedrock · RAG pipelines · Agents and tool use · MCP · Evals · ElevenLabs
- Frontend
- React · Next.js · TypeScript · Tailwind CSS · shadcn/ui · Redux · MobX
- Mobile
- React Native · Expo · Flutter · iOS · Android · Detox · Maestro
- Backend
- Node.js · GraphQL · NestJS · Python · FastAPI · Django
- Data & cloud
- AWS Lambda, SAM, Cognito, S3, DynamoDB, Amplify · PostgreSQL · Redis · MongoDB · GCP · Firebase
- Product
- Stripe billing · RevenueCat · Meta Pixel · Feature flags · CI/CD
About David 05 questions
David Lopena is a software engineer and AI engineer with 12 years of experience building web, mobile and AI products for companies in the US, UK and Asia, including LLM features, RAG pipelines and AI agents running in production.
Who is David Lopena?
David Lopena is a software engineer and AI engineer with 12 years of experience building web, mobile and AI products for companies in the US, UK and Asia. He currently builds AI claims tooling at Paiv, where he leads the Philippine engineering team.
What kind of AI engineering does David Lopena do?
He builds AI features that run in production: real-time LLM chat on Claude and OpenAI, retrieval-augmented generation (RAG), voice input with ElevenLabs, and agents with tool use, deployed on AWS. At Paiv he built an intake agent that turns roof inspection photos into a damage assessment and a draft insurance claim.
What is David Lopena's tech stack?
TypeScript, React, React Native and Next.js on the front end; Node.js, Python, GraphQL, NestJS and FastAPI on the back end; AWS, GCP and Firebase for infrastructure; Claude, OpenAI and AWS Bedrock for AI.
Is David Lopena available for hire?
Yes. He is open to software engineering and AI engineering roles, full-time or contract, working remotely from UTC+8 and used to overlapping with US and UK hours.
How do I contact David Lopena?
Email [email protected] or message him on LinkedIn at linkedin.com/in/david-lopena. His résumé is available as a PDF on davidlopena.com.
Hiring an engineer?
Let's talk.
Open to software engineering and AI engineering roles. Full-time or contract, remote. It's --:-- for me right now (UTC+8).