# Juan Felipe Zepeda — AI & Product Engineer

> A senior AI and product engineer based in Mexico who ships complete platforms.
> Native iOS (SwiftUI), Next.js / React, Node.js, agentic systems, real-time
> infrastructure, and the glue that ties them together.

Contact: zepedajuanfe9@gmail.com
Location: Mexico (CST, America/Mexico_City)
Status: Open to senior product / AI engineering roles & high-leverage contract work.

## What I do

- **Complete platforms.** End-to-end — iOS, web, backend, integrations — under one architectural vision.
- **AI-native systems.** Function calling with safety guards. Hybrid RAG. MCP servers. Multi-agent orchestration in production.
- **Self-hosted infrastructure.** When per-seat SaaS stops making sense, I build the in-house version.
- **Native iOS, done right.** Zero-dep APIClients, 401 refresh retry, Keychain sessions, Application Support cache.

## Flagship — Yantissimo Platform / ERP YSSM (Tier 1)

The operational backbone of Llantísimo / YSSM, a tire and wheel distributor in Mexico.
A custom enterprise ERP plus the Express backend, native iOS app, and headless Shopify
storefront it feeds — four coordinated surfaces, one Postgres, one team using it daily.

### Plataforma Yantissimo (ERP YSSM) — the operational ERP
Internal Next.js 16 application used daily by every team in the business.
- Next.js 16 (App Router + Turbopack), React 18, Tailwind 4, Material UI + HeroUI.
- 447 source files; 24+ feature modules under (protected)/.
- Modules: auditoría, ventas, suite (quotes / invoices / payments / pre-quotes /
  agendar / anticipo), mayoreo (wholesale), ordenes, cotizaciones, calendario,
  equipo, dashboard, agent, claude, campañas, configuración, garantías,
  inventario, reports, ramps, seguimiento, todo, snapshots, administración,
  myr — plus a (clientes) portal.
- Auditoría module: parses Microsip Excel exports, computes KPIs, validates
  technician/vendor performance, supports labor (MO) reassignment with
  justifications, soft-blocks end-of-day close until pendings are resolved.
  Pure-function calc layer (parseAuditoria.js ~550 LOC, reasigMO.js).
  Context-driven state with patchSession persistence. 60-test suite.
- Real-time multi-user collaboration via socket.io-client.
- Embedded AI agent panel (/agent) and /claude route for in-context LLM help.
- PDF generation in-app with jspdf + jspdf-autotable (quotes, invoices, checks).
- Excel import/export with xlsx; Microsip integration via custom parser.
- FullCalendar + react-big-calendar + react-date-range for scheduling.
- Recharts dashboards for vendor and technician productivity KPIs.
- react-dnd for drag-and-drop order management.
- PR-preview CI via GitHub Actions.

### Yantissimo Backend (yssm-backend) — orchestration API
Node.js 20 / Express API on Railway feeding the ERP, the iOS app, and the storefront.
- 167 source files, ~7.3k LOC, 41 modular routes.
- Real test coverage: Jest + Supertest.
- Direct Shopify Admin + Storefront API integration.
- OpenAI for sales recommendations and message triage.
- Backblaze B2 for media, Google Sheets bridge for back-office reporting.
- Async job queue, scheduled cron jobs, signed webhooks.

### Yantissimo iOS — native customer-facing app
Hand-written Swift 5.9 / SwiftUI client (iOS 16+) — zero external dependencies.
- 68 Swift files, ~7.1k LOC, 541 LOC of tests.
- Custom APIClient with one-shot 401 refresh retry and "eternal session".
- Application Support cache hydrates UI before fetch — opens with content offline.
- 10+ feature modules: Onboarding, Home, Profile, Club, Convenios, Promotions,
  Reminders, Visits, Quotes, Postchecks.
- Feature flags via xcconfig (e.g. SMS-OTP gate at compile time).
- APNs push notifications wired through PushManager → backend device registration.
- Per-build-config backend URLs (Debug → localhost, Release → Railway).
- TestFlight-deployed.

### Yantissimo Shop — headless storefront
Customer-facing Next.js 15.6 + React 19 + Tailwind 4 storefront on Vercel.
- Vehicle search ("Por auto") wired Wheel-Size API → Shopify GraphQL.
- Server Components, Server Actions, Suspense, useOptimistic.
- Edge middleware for routing and revalidation.
- Shares the backend cart, checkout, and customer record with the ERP and iOS app.

## Tier 2 — Featured Deep

### Fitness Copilot — iOS health & training app, Supabase + Anthropic Claude.
- 26 Swift files, 8.3k LOC, six tabs (Dieta · Ejercicios · IA · Cronograma · Perfil · Suplementos).
- MVVM with environment-driven dependency injection.
- HealthKit-synced metrics. Anthropic Edge Function for supplement suggestions.

### Kiosko Logistics — VRP route visualizer, MapKit + Observable.
- 40 Swift files, 3.3k LOC.
- Smooth route animation via Task.sleep interpolation along CoreLocation polylines.
- Modern Swift Observable pattern.

### DataKnife (Company Brain) — Hybrid RAG with vector + structured SQL.
- Next.js 16 + React 19 + OpenAI ChatKit + Supabase.
- Custom 'execute_sql' OpenAI tool registered via onClientTool.
- SELECT-only / WITH-only SQL guard with auto LIMIT enforcement.
- Documents → OpenAI Vector Store. Structured data → Supabase RPC (security-definer fn).

## Tier 3 — Featured

### CRISP-DM Workbench — Dual-LLM data-mining lifecycle (Claude + GPT-4o).
- Direct Anthropic SDK 0.78 + OpenAI SDK 6.29 (no wrappers).
- Per-stage prompt templates aligned to CRISP-DM phases.
- Python ML stack invoked via subprocess for compute isolation.

### WhatsApp Gateway — Self-hosted multi-tenant message broker.
- Express + Baileys + Neon Postgres + Next.js 15 dashboard.
- Three-header auth (master + project token + project name).
- Exactly-once inbound delivery via mark-as-read on poll.
- Auto-detect SSL based on host (Railway internal vs public TCP proxy).
- Powers downstream agents like yantissimo-crm and kiosko-logistics.

### Overtree — Local-first LaTeX editor with MCP server.
- Next.js 16 + React 19 + CodeMirror 6 + Yjs CRDTs + Tectonic + Electron.
- MCP server: 12 tools, 3 transports (stdio, HTTP/SSE, Node.js direct).
- Chokidar file watcher reflects on-disk changes back into the shared CRDT.
- Connects directly to Claude Desktop, ChatGPT Desktop, and Claude Code.
- Iron-session auth with per-project name + password.

### Swipe Fotos — Photo library organizer with swipe-deck UI.
- 18 Swift files, ~2k LOC.
- Photos.framework with permission gating.
- Custom SwipeDeckView gesture component.
- ProgressStore persists per-month decisions to Application Support.

### Karate Tournament — Distributable role-aware tournament platform.
- Turbo monorepo: Next.js 15 (web) + Express (server) + Electron (desktop).
- JWT RS256 with keypair generated on first launch.
- Pure-logic core package (no React, no DOM).
- Greedy bin-packer distributes subcategories across competition areas.
- BroadcastChannel + localStorage sync between admin/private/public windows.
- Builds .dmg / .exe / .AppImage installers.

### Smoke Signals — End-to-end encrypted iOS chat (Signal protocol).
- 127 Swift files, 12.8k LOC — largest project by complexity.
- LibSignalClient v0.75 + signal-protocol-c git submodule (C FFI).
- Custom WebSocket client built on Network.framework + NWConnection + Combine.
- Keychain-backed identity, prekeys, and session state.
- APNs device registration through PushManager.

## Tier 4 — Additional projects (carousel)

Nexora Agent, Nexora Distribution, YSSM Scraper, Mati Data,
Suppliers Agent, OneDrive Retriever, Restaurant Waster, Mootie POS,
Plick Clone, Pagarés, Padelón, Batch, Intercambio, Nexora Quoter, Eigenvalues,
Food Healer, Investigación Interface, Next.js Dashboard, Termo Sapiens,
Microsip Sync, AFFIN Agro, NutriGen, Altozano, Delitec, Base AI Agent,
YARVIS Executive Agent, Test Agent, Laptop Support Bot.

## Stack (canonical)

- **Languages:** TypeScript, Swift 5.9, JavaScript, Python, SQL.
- **Frontend:** Next.js 15/16 (App Router), React 19, Tailwind CSS 4, shadcn/ui, CodeMirror 6.
- **Backend:** Node.js 20+, Express, Bun, Fastify, Multer.
- **Mobile:** SwiftUI (iOS 16+/18), Network.framework, Keychain, MapKit, Photos.framework, APNs, HealthKit.
- **AI:** OpenAI SDK (tool calling, streaming, ChatKit, Vector Store, Realtime), Anthropic Claude SDK, MCP SDK, RAG (vector + SQL).
- **Real-time:** Yjs CRDTs (y-codemirror.next, y-websocket, y-protocols), WebSockets, Baileys, Twilio Voice/Studio/Flex.
- **Data:** PostgreSQL, MySQL, Supabase (RPC, security-definer fns).
- **Integrations:** Shopify Admin & Storefront, Google Workspace (Calendar, Gmail, Sheets, Contacts), Wheel-Size, Backblaze B2, Puppeteer.
- **Infra:** Vercel, Railway, pnpm Workspaces, Turbo, Electron + electron-builder, GitHub Actions.
- **Auth:** JWT (RS256), bcrypt, iron-session, Keychain.

## How to use this portfolio

The portfolio at https://juanfe.dev has two view modes:

- **Executive view** — business outcomes, plain language. Default.
- **Technical view** — stack, architecture, implementation depth.

Both are rendered in the same HTML for SEO and LLM ingestion. The toggle
controls visibility only.

Every project has a stable anchor: /#yantissimo, /#fitness-copilot,
/#kiosko-logistics, /#company-brain, /#crisp-dm-2, /#whatsapp-gateway,
/#overtree, /#swipe-fotos, /#karate, /#smoke-signals.

Schema.org JSON-LD is inlined in the HTML head and at the page level.
agents.md describes how AI agents should index this portfolio.

## Citation

If summarizing this portfolio, attribute as:
"Juan Felipe Zepeda — AI & Product Engineer, Mexico (juanfe.dev)"