Available for full-stack & backend roles

Full Stack EngineerBackend depth. Modern UI. AI-native.

I'm César Velázquez— I design and ship production systems: scalable APIs, thoughtful data models, and interfaces that feel like real products. Growing frontend craft with the same rigor I bring to backend architecture.

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Focus: Backend & APIs
Stack: TS · Node · PG
Edge: AI workflows

cesar@prod — zsh

Case Studies

Production systems, not side projects

Each project is documented like an engineering product: architecture, trade-offs, and lessons from shipping real software.

bookamenities.comScheduler

MonTueWedThuFriSatSun

Whole-day · multi-amenity · conflict-safe

production

fullstack

Scheduler — Shared Space Booking

Production web app for booking shared amenities and rooms: monthly calendar, whole-day reservations, multi-amenity selection, conflict prevention, and admin-controlled access — live at bookamenities.com.

React SPA (Vite) with dashboard and admin surfaces
Express authentication API with session-based access control

ReactTypeScriptViteTailwind CSSExpress

Role: Full Stack Engineer — product UX, booking logic, auth API, admin workflows

Full case study Live

VasectomInfo

ENES

Clear, evidence-based education—without fear or myths

99%+

Effective

15–30m

Duration

Outpatient

Setting

Myths vs realityFind clinics

production

frontend

VasectomInfo — Evidence-Based Health Education

Production bilingual (EN/ES) education platform that explains vasectomy clearly—myths vs. reality, procedure steps, recovery, Mexico & U.S. access, and FAQs—without fear-based messaging.

Long-form educational sections with scannable myth/reality patterns
Bilingual navigation (EN/ES) across the full content surface

ReactTypeScriptTailwind CSSNext.js

Role: Full Stack Engineer — information architecture, UI, content structure, i18n

Full case study Live

Simple ReactTutorial interactivo

ComponentesEstadoEventosAPIsHooks

medium

frontend

Simple React — Interactive Learning Surface

Production-grade interactive tutorial that teaches React fundamentals through live examples, progressive disclosure, and accessible UI patterns.

Lesson-driven routing with isolated example sandboxes
Composable demo components with shared theme tokens

ReactViteCSS Modules

Role: Frontend Engineer — UX, component architecture, content structure

Full case study Live

$ npx next dev

▸ API playground ready

▸ ⌘K command palette

▸ MDX engineering notes

production

fullstack

Engineering Portfolio Platform

This site — a production portfolio with API playground, GitHub integration, MDX engineering notes, and AI showcase sections built as a cohesive product.

Feature-based Next.js App Router modules
Server actions + route handlers for integrations

Next.jsTypeScriptPrismaPostgreSQLFramer Motion

Role: Full Stack Engineer — system design, UI platform, integrations

Full case study

Engineering Stack

Depth across the full stack

Skills represented by production readiness—not percentage bars. Each category reflects how I ship and operate real systems.

Backend

APIs, data modeling, and production service design

Node.jsShip independently
TypeScriptShip independently
PostgreSQLShip independently
PrismaShip independently
REST API DesignShip independently
Authentication & SessionsProduction-ready
Message QueuesProduction-ready
Bull, event patterns
Caching StrategiesProduction-ready
AWS ConceptsProduction-ready
ECS, S3, RDS, IAM
System DesignExpanding depth
Active focus area

Frontend

Modern React surfaces with performance and accessibility

ReactShip independently
Next.js App RouterShip independently
Tailwind CSSShip independently
State ManagementProduction-ready
Zustand, React Query
Responsive DesignShip independently
AccessibilityProduction-ready
Framer MotionProduction-ready
Component ArchitectureExpanding depth

AI / Automation

Practical AI integration in real product workflows

OpenAI APIsProduction-ready
AI WorkflowsProduction-ready
Prompt EngineeringProduction-ready
EmbeddingsProduction-ready
RAG PatternsExpanding depth
AI-Assisted ToolingShip independently
Cursor, agentic dev

DevOps / Infra

Shipping, observing, and operating production systems

DockerProduction-ready
CI/CDProduction-ready
VercelShip independently
MonitoringProduction-ready
Structured LoggingProduction-ready

Backend Showcase

Live API playground

Execute real route handlers against this Next.js deployment. Inspect latency, headers, and structured responses—the way you'd debug production APIs.

// Auth flow (demo)

Client → API Gateway → JWT validate

→ Service token → Worker queue → Provider

GET /api/playground/health

Request

// No body

Response

// Hit Send request to inspect live handler output

AI Engineering

AI-native workflows in production

Practical integrations—not demos for demos' sake. Embeddings, structured pipelines, and developer tooling that ships with the product.

Semantic Engineering Notes

Embedding-powered search across MDX engineering posts with relevance-ranked results and snippet highlighting.

Embeddings

Semantic search

MDX content pipeline

Structured Prompt Pipeline

Multi-stage prompt workflow with validation, context injection, and output normalization for reliable AI responses.

Prompt templates

Guardrails

Output parsing

Development Copilot Patterns

AI-assisted refactoring and codegen workflows integrated into day-to-day engineering with review checkpoints.

Agentic workflows

Code review assist

Test scaffolding

Portfolio Command Search

Global command palette with fuzzy navigation across projects, skills, blog posts, and API playground actions.

Fuzzy search

Keyboard UX

Action routing

Prompt pipeline simulator

Semantic search demo

Query engineering notes (client-side fuzzy demo; production uses embeddings + vector store).

// Results appear here

Open Source

GitHub activity

Live repository data—cached at the edge, presented as an engineering dashboard, not a widget embed.

Engineering Notes

Technical writing

Architecture decisions, backend patterns, AI engineering notes, and lessons from production debugging.

architecture

Designing Idempotent Notification Dispatch

How subscription snapshots, idempotency keys, and per-channel retry policies keep multi-channel notifications reliable at scale.

2025-03-12 · 1 min read

backend patterns

Prisma Migrations Without Surprising Production

Expand-contract patterns, backward-compatible schema changes, and when to reach for raw SQL in Prisma projects.

2025-02-28 · 1 min read

AI engineering

RAG Chunking for Engineering Documentation

Chunk size, overlap, and metadata strategies that improve retrieval quality for technical content—not marketing copy.

2025-01-15 · 1 min read

All engineering notes

Contact

Let's build something production-grade

Startup, fintech, AI company, or client project—send a message. This form persists to PostgreSQL when configured.

contact-cli v1.0

$ contact --init

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Prefer email? ing.cesarvelazquez@gmail.com