AI / LLM Engineer · Senior Full-Stack (15+ years) — San Francisco, CA, US · Authorized to work in the US
AI/LLM engineer and senior full-stack engineer with 15+ years shipping and scaling production platforms. Currently founding engineer at FlooxAI, building an agentic platform (35+ connectors, 100+ tools, Claude/GPT/Gemini/Llama via OpenRouter, RAG over pgvector and Qdrant, thousands of agent runs per week) and author of Turnstile, an open-source LLM proxy that cut our AI spend ~35%. Previously: zero-downtime database sharding at Deliveroo, payments lead for 1.5M subscriptions at BarkBox, Apple/Google Wallet hotel keys across 4,000+ hotels at Canary, and founder of a 15-engineer software house. Python, TypeScript, Go, Ruby · FastAPI, Next.js, Rails · AWS. Based in San Francisco, authorized to work in the US.
Founding engineer on an agentic AI platform that connects LLMs to the business tools people already use (HubSpot, Salesforce, Gmail) and to third-party MCP servers, so agents can carry out real multi-step work.
Built the agent runtime connecting LLMs to 35+ business connectors and 100+ tools via LangChain, Composio, and third-party MCP servers — running thousands of agent runs per week.
Multi-model routing across Claude, GPT, Gemini, and Llama via OpenRouter, with RAG over pgvector and Qdrant.
Deployed Turnstile (my open-source LLM proxy) in front of production agent traffic, cutting AI spend ~35% through per-session budgets and runaway-loop detection.
Designed credit-based agent workflows for multi-step tasks: analyzing analytics and graphical data, preparing events, and drafting OKRs.
Shipped the full stack end to end — FastAPI backend, Next.js frontend, and React Native mobile.
Lead developer on the hotel guest journey — mobile room keys and the in-hotel digital compendium (upgrades, room service, amenities) — live across 4,000+ hotels.
Led development of Apple Wallet / Google Wallet mobile room keys for chains including Wyndham and IHG, integrating Apple PassKit and the Vostio and Dormakaba lock SDKs.
Owned the upgrades and room-service flows of the compendium across frontend and backend, including Stripe payments (Python, TypeScript).
Built the tipping and feedback service, integrated with Google and TripAdvisor.
Led full-stack development of tools for UK local governments to manage council homes, tenants, and tenant–council communication, built to GOV.UK standards and accessibility requirements (Ruby on Rails, JavaScript, AWS).
Led a team of 3 building and optimizing council-management tools.
Built systems for benefits and payment collection from council homes.
Brought UX and UI to GOV.UK accessibility standards, driving meaningful gains in tool adoption.
Planned and executed deployment strategies that streamlined production releases and cut downtime.
Worked across the platform for the UK's leading food-delivery service, focused on database performance and a large-scale, multi-market sharding effort (Ruby on Rails, PostgreSQL, AWS).
Drove the zero-downtime sharding of the monolithic PostgreSQL database — migrated to UUID keys and split it into 20+ shards across market areas (UK, EU, Emirates) to absorb major growth in traffic.
Cut the top-10 slowest queries from ~5s to ~350ms average through denormalization and index improvements.
Led the payments team (4 engineers, 1 QA) and was a key developer in warehouse management and fulfillment for a subscription business that grew past 2 million subscribers (Ruby on Rails, JavaScript, TypeScript, Vue.js, AWS).
Owned payments end to end for 1.5M active subscriptions — ~700K recurring charges per month across recurring and gift subscriptions, gift cards, and multiple recurrence models, integrated with Recurly.
Built the assignment logic determining which products shipped for each subscription.
Built warehouse-management and fulfillment features, integrating Pitney Bowes.
Led a team of 6 on a high-traffic marketplace for the game and hobby industry — 1,200+ online stores, ~2M orders/month, 5M monthly active users.
Built an Elasticsearch cluster with geocode search over hundreds of millions of records, cutting unified search from 20+ seconds to ~1 second.
Added frontend caching and a JSON layer to keep the high-traffic platform fast.
Led a datacenter migration of 40+ servers/instances — DNS, PostgreSQL, MySQL, EC2, and S3.
Founder & Lead Engineer — RubyThree Information Services
Feb 2010 — Oct 2015
Dublin, CA
Founded and ran a software house of 15 engineers delivering Ruby on Rails APIs, JavaScript frontends (React, Angular, Ember.js), and native iOS (Swift, Objective-C) and Android apps for clients.
Hired and led a team of 15 engineers across backend, web, and mobile delivery.
Hands-on architecture and delivery lead for client projects from Rails APIs through React/Angular/Ember frontends to native iOS and Android apps.
Freelance Software Engineer — Self-employed
2008 — Feb 2010
Web development for clients in PHP, Perl, and JavaScript.
02Public work
Open Source
Turnstile — session-layer circuit breaker for LLM / agent traffic
A transparent streaming proxy between an app and any LLM provider that meters every agent session in real time and trips a circuit breaker the instant one session goes rogue (a runaway agent loop or a blown budget) — without taking down the rest of the app. Drop-in (swap one base URL, no SDK changes), session-precise, fail-open. Running in production at FlooxAI, where it cut AI spend ~35%.
Go data plane (stdlib only): streaming proxy, provider adapters for OpenAI, Anthropic, Gemini, and OpenRouter, session resolution, metering/pricing, and synchronous pre-execution enforcement.
~6 µs median added latency, self-instrumented, with a CI latency gate that fails the build on regression.
FastAPI control plane (PostgreSQL, Redis) and Next.js dashboard with live telemetry over WebSocket; raw prompts and API keys are never persisted.
03Capabilities
What I build
/Backends & APIs
FastAPI services
Production APIs with JWT auth, SQLAlchemy 2 + Alembic migrations, PostgreSQL, REST + WebSocket — deployed behind nginx + systemd.
Event-driven microservices
Several small services around an Events API hub with webhook dispatch and a JWT authority — for when one monolith isn't the right shape.
Background jobs
Celery + Redis for long-running and scheduled work: enrichment pipelines, async LLM calls, and fan-out tasks.
/Web, Mobile & TypeScript
Next.js web apps
App Router + React 19, TypeScript, Tailwind, shadcn. Typed API clients, zod validation, and HTTP + WebSocket against the backend.
React Native mobile
Cross-platform apps with HTTP + WebSocket + FCM push, deep links, and App Store / Play Store releases via fastlane.
Typed end to end
TypeScript from the API contract through the client — domain types mirror the backend models so the whole stack stays honest.
/AI & Agents
Agentic apps with LangChain
Persistent LLM chat where the model calls tools wired to real services and the database, with replies streaming token-by-token over WebSocket.
Tool-calling on real data
LangChain @tool wrappers over service operations, context-injected user + DB session — the model acts on real records, never raw SQL or secrets.
Third-party tools via Composio
Web search, Gmail, Slack and more as fallback tools alongside native ones, enabled per-deployment from a DB-backed admin registry.
/Product surfaces
Visual page / storefront builder
Composable page components with a drag-and-drop admin canvas and a public renderer — non-devs compose pages from typed blocks.
Ecommerce + Stripe
Product catalog, cart, checkout, and orders — with Stripe payments, saved cards, and subscriptions.
Organizations & multi-tenancy
Orgs, members, roles, and invitations — the backbone for B2B and team-based products.
Media, tags & domains
Org-scoped media on S3, polymorphic tagging, and in-app domain registration + DNS through a registrar API.
/Ship & operate
Domain → production, end to end
Register a domain, deploy API + frontend to a server, wire DNS, and serve over HTTPS — automated. (This very site shipped that way.)
Operations & reliability
CI/CD, health checks, CORS, staging/rollback, backups, Sentry, transactional email, security headers, and rate limits.