Leon Sosa

Always willing to learn Back-End Developer with more than 5 years of experience in developing scalable and efficient solutions using technologies such as Python, Laravel, and Node.js. I have improved system efficiency by 70% by integrating third-party APIs and reduced database errors by 60%. Passionate about implementing agile methodologies and optimizing processes.

I consider myself a dynamic, committed and responsible person, capable of taking on new challenges and adapting to new work environments. I really like working remotely and meeting new people and cultures.

Full Stack developer at Epayco (2025-05 – Present)

• Designed and implemented multiple modules from scratch for transaction creation, ensuring scalability and traceability.
• Developed and maintained RESTful APIs using NestJS connected to MySQL via Prisma ORM, handling complex dual-database architecture (read/write separation with sync logic)
• Built a specialized NestJS module to read cloud-hosted.txt files, using Redis to determine which merchants to affect based on file content
• Created a shared NestJS package to eliminate redundant code across microservices, improving maintainability and team velocity.
• Used Docker extensively for local development, ensuring consistent environments and smooth onboarding.
• Integrated frontend components with a Symfony-based backend and Elasticsearch, focusing on usability and performance.
• Transitioned to frontend development for the ePayco dashboard, designing and implementing new modules using React.
• Collaborated closely with design and backend teams to deliver cohesive user experiences.

Back-end developer at Sipecom / KFC Argentina (2022-04 – 2025-02)

• Collaborate in the integration with third-party APIs, as a billing and collection solution in POS sales systems, increasing their efficiency by 70%
• I reduced by 60% the errors in the stored procedures in the database assigned to the SQL server
• Increase error detection in product information and other elements by 80% with the implementation and deployment of a Telegram boot to support the menu management system
• I managed to improve the response time of my tasks by 45% when we better implemented the agile scrum methodology as a team, performing better
• I increased the number of functionalities integrated into the production system from twice a month to three times a month through improvements in the use of the scrum methodology that positively impacted the team
• Analyze and design the best way to integrate with the company's software delivery service provider
• Continuously collaborate in the integration and improvement of existing modules according to the needs of the client in question
• Integration with APIs of delivery system providers such as Shipday and PedidosYA
• Dockerization of various artifacts that make up the environment of the company's main system

Desarrollador de back-end at Amaxonia ERP S.A (2020-10 – 2022-08)

• Contribute to 70% of the development of the system in Laravel for the management of public personnel payrolls in Panama, with the objective of calculating the amount of said payrolls
• Multiple technical supports were successfully achieved for international clients, generating income for the company
• Development of new functionalities to improve the user experience in the modules for managing schedules for controlling employee entry to the offices, for the amaxonia RP system
• Optimize the user experience in the schedule management module, reducing the time needed to record and consult schedules by 25%
• Made continuous improvements to existing modules, ensuring they met changing customer needs and improving customer satisfaction by 15%
• Creation of a mobile application developed in Flutter for use at points of sale, having as main features: purchase and sale of products, product inventory management, search engine, user login system

Software Developer at Proyectos Luccitti C.A (2018-05 – 2020-09)

• Development of a website for an English institute, improving its SEO and web positioning
• Implemented a custom WordPress theme and specific plugins to improve site functionality, including an online booking system that increased visitor conversion by 25%
• Created custom plugins to integrate specific functionalities, such as an event management system and an advanced contact form, allowing the client to manage their content more efficiently
• Participated in the implementation of usability and design improvements that resulted in a 20% increase in user dwell time on the site
• Provided ongoing technical support and maintenance for multiple websites, resolving performance and security issues that improved site stability by 30%
• Performed regular content and plugin updates to ensure websites were always up to date and secure
• Acquire and apply knowledge in web development and SEO, which allowed me to effectively contribute to projects from the beginning of my career
• I learned to work in a collaborative environment, quickly adapting to the needs of the team and clients

Universidad Bicentenaria de aragua (En curso)