Lima, Peru · Software Engineering, UPC

Backend Developer · .NET

Mathias Jave Diaz

I design secure, scalable REST APIs with ASP.NET Core and Azure for the fintech sector.

Reduced average transfer time to 1 minute per operation for Western Union.

developer.ts

const developer = {
  name: "Mathias Jave Diaz",
  university: "UPC",
  stack: ["C#", ".NET", "Azure", "SQL Server"],
  focus: ["Fintech", "Applied AI", "Security"],
  status: "currently employed",
};

01 / About

About me

From web systems for ISO 17020 inspection bodies to payment and currency-exchange platforms for Western Union.

I'm a Software Engineering graduate from UPC and a developer with over 2 years of experience in enterprise applications, currently in the fintech sector for Western Union. I'm analytical, proactive and results-oriented, focused on teamwork.

I design REST APIs in ASP.NET Core (.NET 8) with Hexagonal and layered architecture, integrate payment gateways and identity providers (Okta, CyberArk, RBAC) and work with Azure and Docker in production. My thesis applies Machine Learning and NLP to fraud prevention and was accepted for presentation at BTSym 2026.

Download CV

+2 years in enterprise applications
C# · .NET · Azure main stack
Western Union current client
Spanish · English B1 languages

02 / Experience

Experience

Building and securing web applications for the financial sector and for accredited inspection bodies.

01
ITSIGHT Consulting (client: Western Union)

Junior Software Engineer · Lima, Peru

Feb 2025 - Present
Key results
- Reduced the average WebFX transfer time to 1 minute per operation by integrating the Ligo API into a centralized payment-provider API, itself integrated into WebFX.
- Remediated 30 critical and high vulnerabilities reported by Checkmarx in the Poseidon Peru project, avoiding delays in the production release.
- Cut accounting book generation time from 5 minutes to 50 seconds per book.
- Successfully migrated 8 Visual Basic .NET modules to .NET Core 8 in the accounting and tax area, handling accounting books with over 1,000 records.
- Automated traceability reports for grouping accounting entries.
- Design and development of REST APIs in ASP.NET Core (.NET 8) using Hexagonal, MVC and layered architecture.
- System integration through REST APIs with external payment gateways (Ligo and Pago Efectivo), with custom middleware and automated billing flows.
- Implementation of authentication and authorization with identity providers (Okta, CyberArk) and role-based access control (RBAC).
- Traceability through logging to monitor and detect incidents in production and non-production environments.
- Use of Azure services in production applications: Blob Storage, Key Vault, App Service and Azure Database for MySQL.
- Maintenance of the WebFX project for web-based currency exchange, with a scalable architecture applicable globally.
- Maintenance of back-office applications with progressive .NET upgrades (5, 8 and 10) under Microsoft LTS policies, and optimization of business rules through SQL Server stored procedures.
- Migration of legacy Visual Basic .NET modules to .NET Core 8, ensuring compatibility and performance.
- Data flows and ETL processes with SQL Server and SSIS for accounting information processed by globally distributed teams.
- Requirements gathering and follow-up meetings with stakeholders to ensure technical alignment.
- C#
- ASP.NET Core (.NET 8)
- SQL Server
- SSIS
- Azure
- Okta
- CyberArk
- RBAC
- Checkmarx
- Hexagonal Architecture
02
Hiperfast SAC

FullStack Developer · Callao, Peru

Jul 2024 - Jan 2025
Key results
- Automated the search for technical inspection reports, reducing the time from weeks to 10 seconds per certificate.
- Development of web systems for ISO 17020 certificate validation and invoice control with a layered architecture in .NET Core 8 and MySQL.
- Containerization with Docker and production deployment setup, ensuring high availability and portability.
- MySQL query optimization, reducing response times and ensuring transactional integrity in critical operations.
- Technical risk assessment and implementation of security measures in production environments.
- C#
- .NET Core 8
- MySQL
- Docker

03 / Projects

Projects

A selection of client, thesis and academic work, prioritizing fraud prevention, payments and architecture.

Thesis · BTSym 2026
ScamShield — A browser extension designed to reduce the risk of scams when making online purchases

Distributed fraud-prevention solution for e-commerce that estimates scam risk probability with Machine Learning and NLP (DistilBERT fine-tuning with PyTorch/Transformers), deployed on Azure.
- .NET Core
- Flask
- Next.js
- MySQL
- Machine Learning
- DistilBERT
- Azure
View project
Client · UDEP
Amigos UDEP Scholarship Fund — Donation platform

Donation platform with online payments through Niubiz, donation certificates stored in Azure Blob Storage, an admin dashboard with Azure AD authentication, email delivery via Microsoft Graph and reCAPTCHA.
- ASP.NET Core 8
- Clean Architecture
- Next.js
- Oracle
- Niubiz
- Azure
- xUnit
View project
Client · YAVA S.A.C.
YAVA — Corporate website

Corporate site for a fuel transport and distribution company with 39 years in the market: services, clients, policies and a contact form backed by Azure Functions, deployed on Cloudflare with CodeQL analysis in the pipeline.
- Astro
- TypeScript
- Tailwind CSS
- Cloudflare Workers
- Azure Functions
- GitHub Actions
View project
Client · HIPERFAST S.A.C.
Invoice Validation and Control

Invoice validation and control system for an inspection body with ISO 17020 accreditation, featuring state management and consumption charts.
- C#
- .NET
- Vue.js
- MySQL
- Docker
- Clean Architecture
Client · CORSERSAC S.A.C.
Report Validation

Certificate of conformity validation system for an ISO 17020 accredited body, with customer management features.
- C#
- .NET
- Vue.js
- Node.js
- MySQL
View project
UPC course
Event Space Rental App

Platform with reservation management, payment integration, and a review system. Robust architecture focused on business scalability.
- Flutter
- C#
- Firebase
- PayPal
- CQRS
- DDD
UPC course · Experiment Design
MoviRent — Electric scooter rental

Platform connecting electric scooter owners with renters, built with Experiment-Driven Development: hypotheses, experiment cards, A/B testing and BDD with Gherkin.
- Vue.js
- Flutter
- Docker
- PostgreSQL
- Render
- Gherkin
Personal project
Vivlo

Artificial Intelligence assistant focused on accompanying and caring for patients with diabetes, using foundational cloud models.
- Flutter
- .NET Core
- AWS API Gateway
- AWS Lambda
- AWS Bedrock
UPC course · 7-person team
EcoGuardian

IoT solution for agricultural monitoring with real-time alerts, personalized recommendations, and a distributed architecture.
- ASP.NET Core
- Vue.js
- Flutter
- IoT
- Stripe
- Docker
View project

04 / Stack

Tech stack

The tools I use to build reliable, secure and scalable applications.

Backend

C#
.NET Core / ASP.NET Core
.NET Framework
APIs REST
Python (Flask)
Node.js
xUnit
NUnit

Architecture

Hexagonal
Microservices
Layered
MVC
Modular Monolith
DDD
SOLID
Clean Code

Cloud (Azure)

Blob Storage
Key Vault
App Service
Azure Database for MySQL
Functions
Container Apps
Azure SQL

Security & identity

Okta
CyberArk
Auth0
RBAC
OWASP Top 10
Checkmarx

Databases

SQL Server
Azure SQL
MySQL
PostgreSQL
MongoDB
DynamoDB
Supabase
Oracle Db

DevOps & tools

Azure DevOps
CI/CD
Docker
Git
GitHub
Linux (bash)
Postman

Frontend

JavaScript
React
Next.js
Angular
HTML
CSS
Bootstrap

ETL & data

SSIS
Pandas
Power BI

AI & ML

Machine Learning
FineTuning
PyTorch
Transformers
Scikit-learn

AI-assisted development

Claude Code
OpenCode
Antigravity CLI

Methodologies

Scrum (SFC)
Kanban

05 / Training

Education & certifications

Academic background, research, certifications and awards that complement my production work.

Bachelor in Software Engineering (degree in process)

Universidad Peruana de Ciencias Aplicadas (UPC) · Lima

Mar 2022 – 2026 · Graduate, bachelor's degree in process

Thesis: “Estimating Scam Risk Probability in Digital Purchases”: a distributed fraud-prevention solution for e-commerce with Machine Learning and NLP (DistilBERT fine-tuning with PyTorch/Transformers); .NET Core / Flask backend, Next.js frontend, MySQL; deployed on Azure (Container Apps, Functions, Azure Database for MySQL).
Publication: Jave Diaz, M. A., Avila Asto, A. & Garcia Rojas, F. (2026). “Before the Click: Client-Side Analysis to Mitigate Scam Risk Probability in Digital Purchases”. Accepted for presentation at BTSym 2026.