Oliver Mas

Lead Software engineer

About Me

Senior Full-Stack Developer with 14+ Years of Experience

I bring over 14 years of experience as a full-stack developer, adept at applying design patterns and clean code principles to deliver high-quality,maintainable software. My expertise spans both mobile development (8+ years) using Android, backend architecture with Python (5+ years) and web frontend with React (2+ years).

Over my career, I’ve worked on a variety of projects that all required different technical skills. This gave me the chance to develop strong teamwork and leadership abilities. I learned something new from every project, which has helped me become a constantly improving developer.

I’m passionate about staying current with the latest technologies and leverage them effectively in my work. I’m also a strong advocate for Open Source Software (OSS) and actively utilize tools like Android, Git, VSCode, and Linux distributions (Manjaro) in my daily workflow.




Technology Consultant - FullStack Python React Android

September 2021 - Present

Improve client proyects at Telefónica & Applus

Telefónica - 5GNow/Glider/Neonet (a.k.a OpenGateway):

  • Designed and implemented 3 critical microservices for the backend using FastAPI, leveraging DDD methodology to ensure clean architecture and maintainability.
  • Established automated testing through CI pipelines for continuous integration and delivery.
  • Integrated seamlessly with 3rd party systems like JPU (for SIM QoS connectivity) and Amazon AWS for efficient resource utilization.
  • Implemented real-time telemetry using OpenTelemetry, Prometheus, Loki, and AlertManager, visualized through Grafana dashboards for proactive monitoring.
  • Collaborated with the frontend team using React with MaterialUI, providing technical guidance, support and write code.

Applus - CIMSA ERP+CRM custom solution:

  • Provided ongoing maintenance for existing backend projects written in Python with Flask and FastAPI, ensuring stability and performance.
  • Extended application functionality by implementing new full-stack features, bridging backend (Python) and frontend (React with Redux-Saga).
  • Managed and optimized Microsoft MSSQL scripting for efficient data manipulation and storage.
  • Use of Microsoft Azure Cloud Services.



Lead Software Engineer

August 2015 - September 2021

Driving Loyalty Through Personalised Experiences in Real Life

Start from scratch diverse backend projects writen in Python:

  • Wallet for Google Pay & Apple Wallet backend API with FastAPI (Python+SQLAlchemy) in a dockerized environment.
  • Realtime payment system with Websockets (Django 3 + ASGI).
  • Telegram Bot to manage Mikrotik routers with Django inside Docker container.
  • Web Admin backend with Django.

Also supporting and refactoring core projects adding automatization scripts, Unit tests and appliying clean code patterns.

As a UX designer I use all the guidelines of Google provided in Material Design and use Free Software tools for create UI as Inkscape. As a Android developer, I created from scratch this app using my experience in all my previous projects. I’m on constant research of new design patterns, libs and releases for maintain the code fresh and maintenable.



Android developer

October 2014 - August 2015

Our objective is that the user can find his optimal phone plan and find out how much he would spend with other operator with just installing the app

Improve the architecture of the application that was already in production, using design patterns and using the new techniques of compiling Android applications with Gradle. Change the version control system from SVN to GIT. Teamwork giving internal talks to improve the technical knowledge of the team.

Gowex - We2


Android developer

October 2013 - September 2014

The We2 Social Wi-Fi platform includes the Router and the Merchant mobile application to create geolocated ads and promotions, message directly with customers, and review real-time customer insights.

Android developer of We2, social app to connect automatically to We2 Hotspot around the world and other app for merchants to manage these WiFi access point.

We used Scrum tools with Jira as platform of task reports, Git on Bitbucket for repository system.



Android developer

October 2011 - September 2013

Work on several top technological projects (Voice recognition, Virtualization, Videoconference and XMPP)

TuMe: Yarn-android is an Android communications application which can send messages, photos, audio and locations, and allows users to make free calls over WIFI and 3G networks.

Videoconference solution / Tokbox: Analyze, design and develop solutions to include video from server side, with multipoint, cross-platform, and multi sign-in capabilities, for integrate it with other products of Telefonica.

Dual persona: Android app for add two independet profiles at the same mobile with two differents number and two different Android OS.

Talkie: Messaging app with some extras gestures like send kisses when you kiss the phone screen.



Technological consultant

September 2010 - September 2011

I was involved in developing the Android apps from scratch also maintain already coded apps.

Llamar a casa: Do international calls with calls national cost.

Portal UAX / Portal Docente UAX: App for teachers and students for review the schedule, send practises…

eTaxi: One of firsts apps for Taxi in Madrid.

Talky: Android app for realtime chat.




September 2007 - September 2008

International financial project developed in COBOL language for IBM MAINFRAME environment.


Universidad Rey Juan Carlos

Master on Free Software

2010 - 2012

Extensive knowledge about software licenses, how they should be applied correctly. Lead a Free Software project based on examples that already exist. History and philosophy behind Free Software.

Universidad Alfonso X El Sabio

Ingeniero en Administración de Sistemas Informáticos

2008 - 2010

I learnt Android because it is my final year project. I ported a project in J2ME from Cenatic foundation, which can visualize ODF files. During its development, I had to make the presentation for the ODF Plugfest 2010 in Granada.

IES Ribera del Tajo

Administrador de Sistemas Informáticos

2005 - 2007

I learned the following programming languages: C, Borland C++ Builder HTML, CSS, JavaScript, VBScript, ASP DataBases language: SQL, PL/SQL

A Little More About Me

Alongside my interests software engineering some of my other interests and hobbies are:

  • Dance Bollywood 🕺
  • Play ukulele & guitar 🎸
  • Maker 🤖