Available for freelance projects

Andrés Buelvas

Full Stack Developer · Integrations, Automation & AI

Node.jsReactTypeScriptPythonAWSAI · LLM

Who I am

About me

7+years of experience

Computer Engineer with 7+ years building scalable backend systems, fintech platforms and AI-powered pipelines. Specialized in microservices, event-driven architectures and LLM integration.

Available for freelance projects

Download CV

Education

2013–2019

Computer Engineering

Universidad Simón Bolívar

2025

Diploma in Software Architecture & Cloud

Pontificia Universidad Javeriana

What I do

Services

API integrations

I connect your app, store or website with the tools your business uses: Stripe, Plaid, CRMs, ERPs, payment gateways or any REST or SOAP API.

n8n automations

I automate repetitive work like lead follow ups, reports, notifications and invoice processing, so your team saves hours every week.

AI features

Chatbots, data extraction from PDFs and images, document classification, and help choosing the right model without overspending.

Full stack apps

From a single feature to a complete MVP, with Python and Node.js backends and React or Next.js frontends.

Shopify & WordPress

Custom features, theme and plugin fixes, and integrations with your other tools.

Mentoring

One on one mentoring for junior developers, in English or Spanish: code reviews, architecture and building real projects together.

Tell me what you need and I'll reply with a simple plan and a fixed price

Contact me →

My journey

Experience

Apr 2025 – Present

NextFaze

Backend Engineer

Backend engineering focused on AI-powered document intelligence and enterprise systems integration, working across LLM pipelines, OCR providers, and middleware automation.

NestJSFastAPILangChainAWSClaude

Apr 2019 – Jan 2025

SmartHop

Software Engineer IC5 / Engineering Manager

Six years across three roles growing from engineer to tech lead, building a Fintech platform for trucking fleet management.

Node.jsReactMongoDBRedisStripe

Jul 2018 – Apr 2019

CIDITEL-VE / Latinux Inc

Backend Engineer

Backend development for academic systems at a Venezuelan technology company.

PythonWeb2pyBootstrap

Apr 2018 – Jul 2018

Simon Bolivar University

Support Assistant

Support role developing internal academic management systems at Venezuela's top engineering university.

PythonWeb2pyBootstrap

Apr 2025 – Present

NextFaze

Backend Engineer

Backend engineering focused on AI-powered document intelligence and enterprise systems integration, working across LLM pipelines, OCR providers, and middleware automation.

NestJSFastAPILangChainAWSClaude

View all experience →

Technologies

Skills

Frontend

React

Next.js

TypeScript

Tailwind

Remix

Redux

Backend

Node.js

NestJS

Python

FastAPI

Express

Kafka

Infrastructure & DB

PostgreSQL

MongoDB

Redis

MySQL

Docker

AWS

AI & LLM

Claude

OpenAI

LangChain

LALangfuse

MCMCP

Automation & CMS

N8n8n

WordPress

WooCommerce

Shopify

Wix

Tools

Git

GitHub

Stripe

Vercel

Datadog

Jest

My work

Projects

Document Parser

Featured

18 document types classified with over 90% accuracy

AI-powered document processing pipeline supporting 18+ document types using a 10-stage orchestration architecture, hybrid LLM classification and a self-training loop with LLM-as-Judge evaluation.

PythonFastAPIOpenAIClaudeLangChainLALangfuseAWSDocker

EzzyGas

Featured

Mobile app, admin dashboard and real time pump communication in one platform

Fuel management and fintech platform built as a multi-app monorepo (backend, mobile, admin web, station gateway) with a multi-tenant financial system, real-time hardware communication and full cloud infrastructure on AWS.

NestJSNext.jsREReact NativePostgreSQLRedisAWSStripePLPlaid

SmartHop Fintech

Featured

ACH payment system used by 30 to 50 companies

Fintech platform with ACH payments (SmartPay), double-entry accounting ledger, UNIT API integration, fuel cards, payroll and billing modules serving trucking fleets across 30–50 active SaaS clients.

Node.jsReactMongoDBGraphQLRedisStripePLPlaid

AR Management System

Bidirectional AR integration system connecting ServiceChannel (facility management) with FSG (ERP), automating work order data flow end-to-end using Hexagonal Architecture and XState state machines.

NestJSTypeScriptRabbitMQPrismaPostgreSQLRedisDockerDatadog

Photo Post

Social media REST API with 5 independent microservices (auth, users, posts, likes, gateway), Kafka for async event-driven communication, per-service Redis caching and Docker Compose containerization.

Node.jsExpress.jsKafkaRedisDockerJWTJest

CQRS Blog Engine

CQRS-based blog platform with an API Gateway as single entry point, MongoDB for reads, MySQL for writes and RabbitMQ for event-driven synchronization between services. React + TypeScript frontend.

Node.jsTypeScriptReactMySQLMongoDBRabbitMQ

ClueGarden

SaaS subscription platform with Stripe Checkout, Billing Portal and webhook event processing for full subscription lifecycle management, Firebase Authentication and Firestore mirroring for low-latency reads.

Node.jsExpress.jsFirebaseStripeHeroku

Personal Portfolio with AI Assistant

Personal portfolio built with Next.js 15 App Router, hybrid SSR/CSR architecture, AI chat assistant powered by Claude Haiku with tool-calling, bilingual support (ES/EN) and custom design system.

Next.jsTypeScriptReactTailwind CSSAnthropic SDK

Document Parser

Featured

18 document types classified with over 90% accuracy

AI-powered document processing pipeline supporting 18+ document types using a 10-stage orchestration architecture, hybrid LLM classification and a self-training loop with LLM-as-Judge evaluation.

PythonFastAPIOpenAIClaudeLangChainLALangfuseAWSDocker

EzzyGas

Featured

Mobile app, admin dashboard and real time pump communication in one platform

Fuel management and fintech platform built as a multi-app monorepo (backend, mobile, admin web, station gateway) with a multi-tenant financial system, real-time hardware communication and full cloud infrastructure on AWS.

NestJSNext.jsREReact NativePostgreSQLRedisAWSStripePLPlaid

SmartHop Fintech

Featured

ACH payment system used by 30 to 50 companies

Fintech platform with ACH payments (SmartPay), double-entry accounting ledger, UNIT API integration, fuel cards, payroll and billing modules serving trucking fleets across 30–50 active SaaS clients.

Node.jsReactMongoDBGraphQLRedisStripePLPlaid

View all projects →