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WILLIAN CHÁVEZ

Backend Developer · AI & Machine Learning

Node.js · NestJS · Clean Architecture · El Salvador (GMT−6) · Remote-ready

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About me

WILLIAN ALEXANDER CHÁVEZ SERVELLÓN

CLASSBACKEND / AI-ML

XP3+ YEARS

SPAWN POINTEL SALVADOR

Software engineer with 3 years of experience building scalable backend systems and, more recently, digital products powered by AI and Machine Learning. Specialized in Node.js, NestJS and clean architectures, with a track record of measurable efficiency gains. I turn client needs into intuitive, reliable systems — and I am always leveling up.

SPANISHNative

ENGLISHB2

Years XP

Systems shipped

Teams

INVENTORY

Technical skills — hover an item for details

LANGUAGES

Java

JavaScript

TypeScript

BACKEND

Node.js

NestJS

REST APIs

Microservices

MVC

Message Queues

FRONTEND

React

HTML

CSS

DATABASES

PostgreSQL

MongoDB

Redis

SQL Server

DEVOPS & TOOLS

Docker

AWS

Git

GitHub

GitLab

NPM

AI & DATA

Machine Learning

Data Analysis

Predictive Models

PRACTICES

Clean Architecture

Clean Code

SCRUM

XP LEVELS

Node.js / NestJS92

TypeScript90

PostgreSQL85

Docker82

Machine Learning76

React72

Self-assessed levels based on production use over the last 3 years.

QUEST LOG

Work experience

SOFTWARE ENGINEER

Addalitica · Remote · Full-time

ACTIVE QUESTOCT 2024 – NOW

✓Build web services for financial solutions powered by AI and Machine Learning
✓Design and ship interfaces and APIs consumed as a digital product across financial-sector entities
✓Built AddaShield, an explainable fraud-risk scoring API (geospatial ML features, SHAP explanations, audit trail) — FastAPI, PostGIS and AWS (EC2, S3, SNS)
›Build Machine Learning models and run data analysis for financial predictions
›Manage and integrate systems in production environments

PROGRAMMER ANALYST

Secretariat of Innovation · Presidency of El Salvador

COMPLETEDMAR 2023 – OCT 2024

✓Built a national solid-waste tracking and control system — Node.js, TypeScript, NestJS, Docker, MongoDB
✓Handled real-time GPS ingestion with message queues and Redis streams across the national collection fleet
✓Implemented a national human-resources system with React and NestJS
✓Created an accessible system for CONAIPD for people with disabilities

LOOT:+30% EFFICIENCY+40% HR SPEED+50% ACCESSIBILITY

SOFTWARE DEVELOPER

Freelance

COMPLETEDAUG 2022 – MAR 2023

✓Designed a pharmacy web system with Node.js and TypeScript under an MVC architecture
✓Built an inventory-management and stock-control system with React, Node.js and PostgreSQL
✓Implemented a point-of-sale (POS) system for retail transactions

LOOT:+35% ORDER PROCESSING+25% STOCK ACCURACY+20% FASTER SALES

FEATURED BUILDS

Selected projects — architecture at a glance

FRAUD RISK API — ADD A SHIELD

ADDALITICA · 2024 – NOW

Explainable fraud-risk scoring API for financial institutions: geospatial ML features, SHAP explanation per decision, full audit trail.

FASTAPIMLPOSTGISSHAP

GITHUB

ADDAPSYCS — BEHAVIORAL RISK SAAS

ADDALITICA · 2024 – NOW

Multi-tenant psychometric-evaluation platform: versioned questionnaires capture answers plus behavioral events that feed credit-risk scoring.

FASTAPINEXT.JSMULTI-TENANT

GITHUB

NATIONAL WASTE CONTROL SYSTEM

SECRETARIAT OF INNOVATION · 2023

Real-time GPS monitoring of the national collection fleet (~240 trucks): WebSocket ingestion, Redis-streams fan-out, geofence/checkpoint events and batched trajectory history in MongoDB — +30% operational efficiency.

NESTJSREDISWEBSOCKETMONGODB

GITHUB

SIPS — SOCIAL SERVICE PLATFORM

FIA-UES · IN DEVELOPMENT

Digitizes the full social-service lifecycle for FIA-UES: opportunities, applications, officialization, progress reports and certification — hexagonal NestJS 11 + Next.js 16 with BullMQ and full observability.

NESTJSNEXT.JSHEXAGONALBULLMQ

GITHUB