Joaquín is available for hire
Hire JoaquínJoaquín Omar Tumas
Verified Expert in Engineering
Full-stack Developer
Buenos Aires, Argentina
Toptal member since July 28, 2026
Bio
Joaquín is a web UI developer with over 10 years of experience building large-scale web applications for clients, including theDifference, Grupo Montalto, and Roche Sequencing Solutions. His primary expertise is in React, Angular, and TypeScript for bioinformatics and healthcare industries, where he thrives in fast-paced, collaborative environments. Joaquín delivered UIs with 1+ million lines of code while at Roche Sequencing Solutions.
Portfolio
Grupo Montalto
Next.js, OpenAI, Gemini API, Supabase, Redis, Vercel, AI Development...
theDifference
React, Next.js, Node.js, Auth0, WordPress, CSS Animations, Web Security...
Altoros
Front-end, JavaScript, Angular, Node.js, TypeScript, HTML5, CSS, Full-stack...
Experience
- Linux - 20 years
- Front-end - 15 years
- Node.js - 10 years
- Computer Science - 10 years
- React - 8 years
- Next.js - 6 years
- LLM Agents - 2 years
- AI Development - 1 year
Preferred Environment
AI Development, NeoVim Text Editor, OpenCode
The most amazing...
...web application I've built is a large-scale UI with over 1 million lines of code for Roche Sequencing Solutions in the bioinformatics domain.
Work Experience
AI Developer
2025 - 2025
Grupo Montalto
- Led software planning and development for a geriatric assistant webapp with an interactive voice-driven AI assistant.
- Built a Next.js webapp deployed on Vercel with Supabase, Redis, and Vercel Object Storage.
- Integrated OpenAI and Gemini APIs into the application.
- Developed system features to provide resident information, send Telegram emergency alerts, and maintain a control panel with conversation logs and residence-based management.
- Coordinated a 4-person team including a product owner, electronic engineer, and QA engineer.
Technologies: Next.js, OpenAI, Gemini API, Supabase, Redis, Vercel, AI Development, TypeScript, HTML5, Artificial Intelligence (AI), Web Development, MVP Design
Senior Full-stack Developer
2022 - 2025
theDifference
- Completed development of web applications for various projects, ensuring delivery deadlines were met.
- Created animated interfaces with seamless transitions, scroll-controlled animations, diverse graphics, and real-time visualizations.
- Achieved pixel-perfect design consistently across all delivered web applications.
- Handled web security, including 3rd-party authentication and Auth0 flows.
- Integrated WordPress and managed Node.js servers with and without Next.js.
- Coordinated with designers, project managers, and clients to meet expectations.
Technologies: React, Next.js, Node.js, Auth0, WordPress, CSS Animations, Web Security, Full-stack, Web Development, MVP Design, Vercel, Figma to React
Senior Full-stack Developer
2017 - 2021
Altoros
- Built several apps and was part of different teams with English-speaking clients.
- Worked as an interviewer, building materials, and interviewing new employees, all with good results, as we hired good candidates even when they got nervous or had other difficulties in the interviews.
- Participated in the team designing the new career paths for all employees, which required defining clear goals and ways of measuring them.
Technologies: Front-end, JavaScript, Angular, Node.js, TypeScript, HTML5, CSS, Full-stack, Web Development, MVP Design
Senior Web UI Developer
2017 - 2019
Roche
- Implemented UI and UX requirements with unit and integration tests, assuring a very high quality bar for delivered code in the bioinformatics domain.
- Worked with the Cucumber (FLOSS library for e2e testing) team to implement improvements on their library that were beneficial to our tasks.
- Coordinated daily with several different teams to achieve the best results. I gave a company-wide presentation on our work and developments.
Technologies: Unit Testing, Integration Testing, Bioinformatics, Full-stack, Web Development
Full-stack Web Developer and Architect
2016 - 2017
Kidloom
- Developed a Python API using the Google App Engine stack and JavaScript with a custom library-based stack.
- Handled back-end and front-end technical maintenance and development decisions.
- Maintained and deployed several flash and web-based games.
Technologies: Python, Google App Engine, JavaScript, Architecture, HTML5, CSS, Full-stack, Web Development
Senior Front-end Web Developer
2013 - 2015
Hinch.as
- Developed the client-side web interface built on AngularJS.
- Developed JavaScript tools for project management and data migrations.
- Analyzed potential user load and studied measures to optimize application performance.
- Led the team and made important architectural decisions.
Technologies: Angular, JavaScript, Linux, Full-stack, Web Development
Senior Programmer and System Administrator
2010 - 2013
Batanga Media
- Designed and developed a web platform for a radio service with on-demand music listening.
- Researched and implemented bleeding-edge technology to build an SPA that would stream audio to thousands of people.
- Built an in-house event-driven architecture that could provide strong parallelism and allow us to build a Spotify-like interface 10 years before Spotify.
Technologies: HTML5, JavaScript, Backbone.js, Full-stack, Web Development, MVP Design
Experience
Show and Games Rental for Kids
https://rulinymeterete.com.ar/A Next.js website developed for an entertainment company specializing in magic, circus, comedy, and improvisation performances for events of all sizes and audiences of all ages. The site features polished UX patterns, is hosted on Vercel, and integrates Mailgun for reliable contact form submissions. Built using an LLM-assisted workflow with significant human refinement, it delivers a seamless, fully responsive experience across desktop and mobile devices.
Education
2009 - 2011
Bachelor's Degree in Information Technology
University of Buenos Aires - Buenos Aires, Argentina
Certifications
JULY 2026 - PRESENT
Digital Security and Privacy for Individuals and Organizations
FLACSO Ecuador
Skills
Libraries/APIs
React, Node.js, Backbone.js
Tools
Auth0, OpenCode
Languages
JavaScript, TypeScript, Python, Perl, HTML5, CSS
Frameworks
Next.js, Angular
Platforms
Vercel, Linux, WordPress, Mailgun, Google App Engine
Paradigms
Unit Testing, Test-driven Development (TDD)
Storage
Redis
Industry Expertise
Bioinformatics
Other
Front-end, Architecture, NeoVim Text Editor, Full-stack, Artificial Intelligence (AI), Web Development, MVP Design, CSS Animations, Web Security, OpenAI, Gemini API, Supabase, AI Development, Web3, Computer Science, LLM Agents, Figma to React, Integration Testing, IT Security, Data Privacy
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