Guillermo Olmos Ranalli
Senior Software Engineer
Specializing in Java, JavaScript, TypeScript
Expert in React & Spring Development
Guillermo Olmos Ranalli
Based in London, UK
Crafting digital experiences
Experience
Software Engineering Analyst
PagoNxt (A Santander Company)
June 2022 - Present
- I significantly contributed to developing high-performance financial UIs using React and Spring microservices backends.
- I have spearheaded complex platform migrations, enhancing system scalability and performance.
- I served as a primary technical reference across both frontend and backend development for a team of 10+ engineers.
- Implemented and managed robust CI/CD pipelines across changing cloud platforms.
- Designed and maintained RESTful APIs, enhancing system interoperability between frontend and backend systems.
- Mentored junior developers, facilitated knowledge transfer sessions, and conducted code reviews.
- Demonstrated exceptional adaptability and full-stack expertise.
Software Engineering Analyst · Consultant 2 Development
Santander UK Technology
September 2018 - June 2022
- Collaboratively developed and maintained four major financial frontend applications using React and Spring services, enhancing user experience and performance at branch locations and for international transactions.
- Contributed significantly to developing and improving payment systems, including CHAPS and Faster Payments, using Spring microservices to ensure efficient and reliable processing.
- Contributed to designing and developing backend microservices for fraud detection and initial data flow from Elasticsearch, enhancing data management and security.
- Developed in a diverse technology stack in an Agile environment, utilising test-driven development (JUnit 5, Cucumber, Selenium, Jest, Cypress) and pair programming to deliver robust and reliable software solutions with rapid feedback cycles.
- Specialised in payment processing standards including ISO 20022, Faster Payments, CHAPS, and BACS.
- Demonstrated technical expertise across a wide range of technologies.
Software Developer
Makers Academy
March 2018 - September 2018
- Utilised Spring Boot, Thymeleaf, and JavaScript to maintain and update a legacy UI to display payment information, ensuring consistent performance and compliance with business requirements.
- Helped with the adoption and migration to React, enhancing code maintainability and performance, and incorporating TDD and pair programming in Agile.
- Participated in the full software development lifecycle from requirements gathering to deployment.
- Followed Agile practices and engaged in pair programming and test-driven development with the development team.
- Enhanced application performance through optimization and refactoring.
Projects
Conway's Game of Life
June 2024
An interactive implementation of the classic cellular automaton, featuring a dynamic grid where users can toggle cell states. The project showcases React concepts, component-level styling, and modern deployment practices.
Photographer's Portfolio Gallery
July 2024
A responsive and interactive photo gallery for a professional photographer. This project features a masonry layout, image filtering by category, lightbox functionality, and smooth animations. It demonstrates proficiency in modern web development techniques and responsive design.