👋 Hi, I'm

Martin Penabad

Backend Engineer

Building backend systems and payment infrastructure that power financial transactions.

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01.

About Me

Hi, I'm Martin—a backend engineer passionate about building systems that power the digital economy.

With over a decade in software development, I've gone from building mobile apps and interactive kiosks to architecting payment infrastructure that processes transactions at scale. Along the way I've also helped businesses grow through freelance web development and e-commerce work. Today I specialize in backend engineering for fintech, designing the secure, reliable systems that power seamless financial transactions.

When I'm not engineering payment systems, you'll find me running game servers, tinkering with Linux, pushing my limits with cross training, or breaking things in my homelab to figure out how they really work.

🎮 Game Servers🐧 Linux & Homelab🤖 AI Exploration

Technical Skills

C# / .NET Proficient

Java Proficient

Relational Databases Proficient

Swift Advanced

Android Development Advanced

JavaScript Working Knowledge

AWS Cloud Services Working Knowledge

Kotlin Working Knowledge

Docker Working Knowledge

Node.js Working Knowledge

Education & Languages

Certificate in Advanced Java Programming

Fundación Confemetal • 212 hours • 2013

Software Development (CFGS)

San Clemente • Santiago de Compostela, Spain • 2013

Languages

English & Spanish (Native) • Galician (Working) • Portuguese (Conversational)

02.

Experience

Backend Engineer

Mews

Nov 2022 - Present

Developed and maintained secure payment processing systems powering payment flows for one of the leading hospitality platforms in Europe
Integrated with third-party payment gateways to enable seamless payment operations used in thousands of hotels worldwide
Collaborated with financial and security teams to ensure compliance with the highest standards of security and regulatory requirements
Implemented scalable backend services in C#/.NET for high-throughput payment flows
Since July 2025, working with the Acquiring team on payment infrastructure in a new area of the business

C#.NETDockerAzureOpenTelemetrySQLPayment APIs

.NET Developer

STK GDC SL (Softtek)

April 2020 - 2022

Maintained and enhanced fraud detection and compliance systems for a UK-based fintech client serving millions of users worldwide
Improved transaction monitoring engine to process up to 90,000 transactions per day using C#/.NET and AWS cloud services
Managed observability stack with AppDynamics and Splunk; maintained Jenkins CI/CD pipelines and Docker infrastructure on AWS
Mentored junior developers through technical discussions and comprehensive code reviews

C#.NETAWSDockerPostgreSQLMSSQLJenkinsSplunk

Application Management Support

STK GDC SL (Softtek)

October 2019 - April 2020

Provided operations support for major Spanish multinational clothing company
Monitored system health, performance metrics, and service availability
Streamlined operational processes and implemented KPI reporting with automated alerts

Monitoring ToolsSQLOperations ManagementKPI Reporting

Tech Lead / Co-Founder

P-Dub Inc

December 2016 - September 2019

Co-founded and led technical direction for a mobile startup, architecting native apps for iOS (Swift) and Android (Java/Kotlin)
Built a gift recommendation platform with a Node.js REST API backend deployed on Microsoft Azure
Implemented online payment processing with the Redsys payment gateway
Developed a prototype using OCR to analyze utility bills and calculate household energy savings

JavaKotlinSwiftNode.jsAzureFirebaseMS SQL Server

Junior Java Developer

Zemsania - Everis SL

May 2016 - November 2019

Developed custom Java frameworks and applications for Galician Government agencies
Built healthcare integration services with HL7 messaging standards for public health systems
Implemented reporting solutions using Jasper Reports and Mirth Connect integration channels

JavaMirth ConnectHL7PostgreSQLMS SQL ServerJasper Reports

Web Developer

Freelance

January 2014 - Present

Providing PHP web development and WordPress solutions for diverse clients
Building custom WooCommerce backends and e-commerce solutions
Developing responsive web applications with modern JavaScript and CSS frameworks

PHPWordPressJavaScriptMySQLHTML/CSSjQueryREST APIs

Junior Java Developer

Plexus Technologies SL

December 2013 - November 2015

Developed enterprise software for healthcare organizations, government agencies, and private sector
Built interactive kiosk systems and queue management solutions using Java and Android
Created digital signage platforms with integrated backend services

JavaJavaScriptAndroidMySQLMS SQL ServerCSS

03.

Get In Touch

Let's Build Something Amazing Together

I'm always interested in hearing about new projects and opportunities. Whether you have a question or just want to say hi, feel free to reach out!