Marcelo is available for hire
Hire MarceloMarcelo Biffara
Verified Expert in Engineering
Full-stack Developer
Buenos Aires, Argentina
Toptal member since January 20, 2015
Bio
Marcelo is a full-stack engineer and technical lead with 15+ years building production systems in Ruby on Rails, Next.js, Python, and Node.js, now building GenAI products on top of them. He took an AI travel product from zero to MVP in under two months, rebuilt a lending platform's LLM retrieval layer from 50 to 200+ institutions, and built a Shopify app that recovered $200 million in abandoned-cart revenue. He has led teams across three continents and works from Buenos Aires on US hours.
Portfolio
solidcore holdings llc - main
CSS, Contentful, Next.js, HTML, React, TypeScript, GraphQL
Galya Travel AI, Inc.
Full-stack, Minimum Viable Product (MVP), Startups, Architecture, LangChain...
Pablo Martinez
MySQL, React, JavaScript, Next.js, OpenAI, ChatGPT API
Experience
- Ruby on Rails (RoR) - 10 years
- React - 8 years
- OAuth 2 - 8 years
- Facebook API - 8 years
- Elasticsearch - 8 years
- Node.js - 5 years
- SendGrid - 2 years
- ChatGPT API - 2 years
Preferred Environment
Git, MacOS, Terminal, Chrome
The most amazing...
...thing I've built is a GenAI pipeline that turns a single user photo into a complete, bookable travel itinerary in seconds.
Work Experience
Contentful/Next.js Engineer
2025 - 2026
solidcore holdings llc - main
- Architected and built custom Contentful content models, blocks, and Studio/Experiences workflows that gave the marketing team full self-service control over site content, cutting developer involvement in routine content updates.
- Developed and maintained the front end of a high-traffic website using Next.js, TypeScript, and Tailwind CSS, meeting Core Web Vitals thresholds and accessibility standards across the site.
- Integrated Contentful with the company's marketing technology stack (analytics, A/B testing, and personalization) via GraphQL and REST, and optimized deployment workflows across Vercel and AWS to support faster, more reliable releases.
Technologies: CSS, Contentful, Next.js, HTML, React, TypeScript, GraphQL
Senior Full-stack/GenAI Developer
2025 - 2025
Galya Travel AI, Inc.
- Led a greenfield AI travel-planning product from zero to MVP in less than 3 months, owning the technical roadmap end-to-end: architecture, stack selection, application scaffolding, and hiring recommendations for the team that would carry it forward.
- Designed and shipped a GenAI pipeline that turns user-uploaded photos into personalized, bookable itineraries. Combining vision-based aesthetic analysis with destination matching to generate a complete trip plan in seconds from a single image.
- Translated finished Figma designs into a cross-platform web and mobile application with automated booking integrations, delivering a visually polished product.
Technologies: Full-stack, Minimum Viable Product (MVP), Startups, Architecture, LangChain, ChatGPT, OpenAI, React Native, React, Generative Artificial Intelligence (GenAI), Amazon Web Services (AWS), LangGraph
Full-stack Developer
2025 - 2025
Pablo Martinez
- Rebuilt a third-party AI lending platform from the ground up as a fully owned in-house system, eliminating vendor dependency and giving the company complete control over its data, roadmap, and licensing costs.
- Expanded lender coverage from around 50 to 200+ institutions by designing a scalable ingestion and retrieval layer for lender guidelines, so loan officers get recommendations across the company's full lender network instead of a quarter of it.
- Built an AI query interface backed by a structured guideline database, cutting the time loan officers spend hunting for lender requirements from hours to seconds per query.
- Reduced guideline update turnaround from multi-day to same-day through a streamlined admin workflow.
Technologies: MySQL, React, JavaScript, Next.js, OpenAI, ChatGPT API
Lead Developer
2024 - 2025
183 Media
- Rebuilt and enhanced existing software as a Lead Full Stack Developer, creating a streamlined, custom solution from scratch. Integrated various APIs, developed a dynamic dashboard, and ensured seamless, real-time updates to voice search platforms.
- Integrated 3rd-party APIs such as Yext, Checkoutchamp, OpenAI, Klaviyo, Formsort, and Google Geocoding.
- Enabled thousands of businesses to improve their Google Business Profile and their SEO/GEO across multiple LLM services such as OpenAI, Perplexity, Gemini, and Anthropic.
Technologies: Ruby on Rails (RoR), JavaScript, React, PostgreSQL, Artificial Intelligence (AI), Software Architecture, Amazon Web Services (AWS), OpenAI, Klaviyo, Yext, checkoutchamp
Full-stack Developer
2024 - 2024
Fieldcraft, Inc.
- Created a new front-end for the company’s platform based on the designs. Built integrations with the shipment and tracking service (FedEx).
- Developed payment integrations (Stripe) supporting marketplace transactions.
- Integrated an email-marketing solution using SendGrid's API.
Technologies: React, Next.js, Ruby on Rails (RoR), PostgreSQL, APIs, Tailwind CSS, CSS, FedEx API, SendGrid API, Stripe API
Svelte Developer
2024 - 2024
10% Happier, Inc.
- Applied a new design to the web application and updated the Stripe integration.
- Implemented Svelte together with Inertia to build the single-page application.
- Used Linear for ticket management and oversaw the testing process for a successful launch.
Technologies: Svelte, Tailwind CSS, Ruby on Rails (RoR), Inertia, JavaScript, TypeScript, RSpec, Capybara, Git, reCAPTCHA
Developer
2024 - 2024
MiTech Software Solutions Ltd
- Created a service for the client's CRM, enabling them to build a chatbot using WhatsApp Cloud API.
- Built a NestJS service that interacts directly with the WhatsApp Cloud API, makes it easy to send text messages, templates, and quick reply buttons, and marks received messages as read.
- Removed Twilio and its associated costs by interacting with the Meta WhatsApp Cloud API.
Technologies: NestJS, Chatbots, WhatsApp, API Integration, REST API Clients
Front-end Developer
2023 - 2023
Lingo Live Language Services, Inc
- Developed a Rails app that manages coaching engagements for thousand of users using Tailwind CSS, Rails 7, PostgreSQL, and Redis.
- Reviewed team's pull requests and deployed to production an app that serves the company's core business.
- Helped improve the codebase by implementing Ruby interactors and best practices.
Technologies: Ruby on Rails (RoR), HTML, CSS, PostgreSQL, SQL, Heroku, Tailwind CSS, SendGrid, Redis
Full-stack Developer
2022 - 2023
Nextflag S.R.L.
- Built a custom mailing library that lets users easily swap between mailing vendors.
- Integrated Sendgrid's API to replace the default SMTP email Rails integration.
- Created a custom device mailer that integrates with the custom mailing library.
Technologies: Ruby on Rails (RoR), HTML, CSS, JavaScript, Mailchimp, Postmark, SendGrid, Full-stack, Full-stack Development, Back-end, API Integration, REST API Clients
Lead Software Developer
2021 - 2023
AIIR Consulting
- Led a software development team across three continents and time zones. Designed a system architecture for a coaching platform with Fortune 500 companies. Used NextJS, RoR, PGSQL, Redis, Sidekiq, AWS ECS, and AWS EB.
- Led software development for a stress management iOS App using Swift, Ruby on Rails, PostgreSQL, Contentful, and AWS EB.
- Integrated Metabase as a dashboard and reporting system for the whole company. Embedded it into the main coaching app.
- Created a Hubspot integration allowing the coaching platform to display contract information. Created custom Hubspot cards that displayed engagement information in Hubspot from the coaching platform.
- Created Qualtrics surveys integration, allowing the coaching platform to trigger Qualtrics surveys based on events.
Technologies: Ruby on Rails (RoR), Ruby, Sidekiq, Amazon Elastic Container Service (ECS), PostgreSQL, React, Next.js, HubSpot, HubSpot CRM, Qualtrics, Node.js, Technical Leadership, TypeScript, Software Architecture, Solution Architecture, Full-stack, Proof of Concept (POC), Full-stack Development, Metabase, Technical Architecture, Architecture, Back-end, Tailwind CSS, WhatsApp, API Integration, REST API Clients
Full-stack Developer
2020 - 2021
MYRM Technologies, LLC
- Designed system architecture for a finance platform built to replace Salesforce.
- Led the front and back-end teams located in two different time zones.
- Created custom data migration tools from Salesforce files.
Technologies: React, Ruby on Rails (RoR), Redshift, PostgreSQL, Salesforce, Heroku, Full-stack, Full-stack Development, Back-end, API Integration, REST API Clients
Web App Architect
2020 - 2020
Colorado General Assembly
- Created the architecture for the new Colorado General Assembly website, consisting of an admin site, public API, search API, background workers, and a React site.
- Created an importer into Legacy for their old Drupal app, using a REST client and scheduled Sidekiq workers.
- Drafted documentation for the architecture and weekly estimations.
Technologies: Sidekiq, PostgreSQL, Elasticsearch, React, Ruby on Rails (RoR), CTO, Full-stack, Proof of Concept (POC), Full-stack Development, Software Architecture, Solution Architecture, Metabase, Technical Architecture, Architecture, Back-end
Senior Rails Developer
2020 - 2020
Booster Apps
- Created a multi-channel abandoned cart recovery app built on Ruby on Rails 6, using Shopify API, PostgreSQL, Sidekiq, Facebook API, Twilio API, and Mailgun. This app was installed by thousands of merchants and generated $200,000,000 in revenue.
- Implemented Twilio API to send SMS and WhatsApp messages.
- Integrated the Facebook Messenger API to send messages with discounts and checkout links.
- Executed the Mailgun API to send discounts and checkout links.
- Integrated with the Shopify API to get abandoned carts sessions.
Technologies: Mailgun, Twilio API, Facebook API, Shopify API, Ruby on Rails (RoR), Full-stack, Full-stack Development, Back-end
Back-end Engineer
2019 - 2020
ShowplaceHQ
- Created the MVP for a new platform connecting brands with Airbnb hosts using Ruby on Rails, React, ElasticSearch, and PostgreSQL.
- Retrieved data from Airbnb listings parsing the HTML response and extracting information from tags and JSON data.
- Implemented Facebook and Google authentication using OmniAuth.
- Implemented the SendGrid API using templates for transactional emails.
- Created a model for storing images—with original, mid, and thumbnails resolution—uploading all versions to AWS S3.
- Created an AWS infrastructure, setting up EC2, RDS, S3 and loading balancers. Set up SSL configuration, Nginx, and Unicorn.
Technologies: Amazon Web Services (AWS), GitHub, MySQL, Ruby on Rails (RoR), Ruby, Contentful, Heroku, Proof of Concept (POC), Back-end
Lead Developer
2018 - 2018
Puragraft
- Created a Ruby on Rails 4 web app for order analysis and detecting anomalies, implementing Devise for user authentication.
- Created the Excel file import process using AXLSX gem, building customer statistics, and exporting them to PDF using PDKit.
- Generated reports, using Axlsx, in CSV format to show the order analysis, anomalies, and confidence rate.
Technologies: SendGrid, Microsoft Excel, MySQL, Ruby on Rails (RoR), Ruby, Full-stack Development, Full-stack, Software Architecture, Solution Architecture, Metabase, Technical Architecture, Technical Leadership, Architecture, Back-end
Lead Developer
2015 - 2018
Email Delivered
- Built the CSV contact importer process supporting CSV files with over 2 million rows.
- Developed the contact search engine, supporting millions of documents.
- Created an AB testing email engine, supporting automatic AB testing and winner selection.
- Built the smart marketing campaign engine, supporting dynamic campaign flow and timed delayed campaigns.
- Developed smart list segmentation, creating dynamic lists based on custom properties (field values, engagement history, tags, custom fields).
Technologies: Amazon Web Services (AWS), Bootstrap, Redis, MySQL, Elasticsearch, Ruby on Rails (RoR), Ruby, Full-stack Development, Full-stack, Software Architecture, Solution Architecture, Metabase, Technical Architecture, Technical Leadership, Architecture, Back-end
Senior Software Engineer
2013 - 2015
Keepcon
- Created a Ruby gem that reads user-generated content from Facebook pages and inserts them into a proprietary API.
- Developed a Ruby on Rails website to manage and map Facebook pages to user accounts.
- Built a Ruby gem that listens to tweets in real time and inserts them into a proprietary API.
- Programmed a Ruby gem that reads comments from Disqus and inserts them into a proprietary API and, after they are processed, posts moderation results back to Disqus.
- Wrote a Ruby on Rails website for Facebook Page Insights.
- Created a Ruby gem that reads sitemaps and looks for Facebook comment boxes and imports their comments into a proprietary API.
Technologies: Bootstrap, jQuery, Redis, MongoDB, ActiveMQ, Ruby on Rails (RoR), Ruby
Software Developer
2012 - 2013
DC Group Argentina
- Maintained the DescuentoCity website written in Ruby on Rails.
- Created a mailer process to send a custom newsletter to 300+ thousand users using Amazon SQS and multiple AWS workers.
- Integrated Facebook into the website, allowing users to like and comment on each deal, using Facebook JavaScript SDK.
- Built an administration website using Ruby on Rails, Bootstrap, jQuery, and MySQL.
- Coded a deal-sorting algorithm based on user views/clicks.
Technologies: Amazon Web Services (AWS), jQuery, MySQL, Ruby on Rails (RoR)
Software Developer
2012 - 2013
Graion
- Created an Entity Framework extension to generate classes based on a stored procedures result.
- Maintained an ASP MVC online platform for managing television ad placement.
- Implemented a Lucene.net search engine library in a services marketplace site.
- Created a mobile-based website for wine store order processing.
- Created an MVC website to compare real estate property prices based on multiple factors.
Technologies: JavaScript, jQuery, Bootstrap, Microsoft SQL Server, .NET, C#
Software Developer
2011 - 2012
Metrogames
- Created a business intelligence web panel for online Facebook games.
- Built a custom reports platform where users were able to share their reports with other users.
- Wrote a batch process to move and compact SQL server table information to archive tables.
- Developed an online dashboard that aggregates multiple game information.
- Programmed a tool to import users' friend lists from the Facebook API and generate a custom report to analyze game acquisition virality.
Technologies: jQuery UI, jQuery, Web MVC, Microsoft SQL Server, C#
Software Developer
2008 - 2010
Axoft
- Implemented AFIP (government) web services in an invoice system.
- Modernized the system UI, adding new DevExpress .NET components.
- Maintained SQL stored procedures. Custom Views and migration files.
- Created a custom reporting tool in C# using DevExpress components.
- Implemented an LA POS (credit card) payment system in the invoicing system.
Technologies: Microsoft SQL Server, C#, .NET
Experience
Coachingzone: A Coaching Platform for a Company That Serves Fortune 500 Clients
https://aiirconsulting.com/A Ruby on Rails and React coaching platform. As the lead developer, I managed three teams across multiple continents, designing the architecture and the infrastructure. The application helped various types of users, such as HR roles, coaches, coachees, account managers, and administrators.
Showplace HQ
http://www.showplacehq.comA platform that connects brands with Airbnb super hosts built on Ruby on Rails and React. It allows brands to create their campaigns and give away products to Airbnb hosts for free in exchange for content creation and other custom requirements.
Shopify Abandoned Cart Recovery Tool
A Ruby on Rails web app for merchants that allows users to recover abandoned cart sessions by letting them subscribe with an opt-in pop-up using different channels like SMS, WhatsApp, Email, Facebook Messenger, and push notifications.
B2B Marketplace
This is a Next.js and RoR B2B marketplace for food and agriculture, connecting the supply chain and helping suppliers and growers connect with buyers.
I helped expand the functionality for direct offers and requests and improved their search engine to include location filters.
I helped expand the functionality for direct offers and requests and improved their search engine to include location filters.
Education
2010 - 2014
Bachelor's Degree in Computer Engineering
Universidad Abierta Interamericana - Buenos Aires, Argentina
Skills
Libraries/APIs
Facebook API, HTML Offline API, jQuery, React, Ruby on Rails API, Stripe API, Shopify API, Twilio API, Sidekiq, SendGrid API, X (formerly Twitter) API, Mongoid, jQuery UI, Node.js, WhatsApp API, OpenAI Assistants API, Inertia, Plaid API, FedEx API
Tools
ChatGPT, Sublime Text, Git, Microsoft Excel, GitHub, Mailchimp, ActiveMQ, Capistrano, NGINX, SendGrid, Terminal, Amazon Elastic Container Service (ECS), Qualtrics, RSpec, Plaid
Languages
JavaScript, SQL, HTML, Ruby, Unicorn, Transact-SQL (T-SQL), C#, CSS, GraphQL, TypeScript, Python
Frameworks
Ruby on Rails (RoR), ASP.NET MVC 5, OAuth 2, Bootstrap 3, Sinatra, AngularJS, Ember.js, Tailwind CSS, Bootstrap, Ruby on Rails 5, .NET, Chrome, Next.js, NestJS, Svelte, Capybara, Redux, React Native, LangGraph
Platforms
Heroku, Docker, MacOS, Ubuntu, Mailgun, Amazon EC2, Twilio, Amazon Web Services (AWS), Visual Studio Code (VS Code), Contentful, Salesforce, HubSpot, Klaviyo, Yext, Shopify
Storage
Elasticsearch, PostgreSQL, Databases, Microsoft SQL Server, MySQL, Amazon S3 (AWS S3), Redis, NoSQL, MongoDB, Redshift
Paradigms
REST
Other
Back-end, Proof of Concept (POC), Full-stack Development, WhatsApp, API Integration, REST API Clients, Technical Leadership, Technical Architecture, Architecture, CTO, Metabase, Software Architecture, Solution Architecture, Full-stack, OpenAI GPT-3 API, Chatbots, OpenAI, APIs, ChatGPT API, Web Servers, LangChain, Prompt Engineering, AI Agents, Supabase, FastAPI, Web MVC, Amazon Route 53, Computer Engineering, Postmark, HubSpot CRM, OpenAI GPT-4 API, Large Language Models (LLMs), reCAPTCHA, Web Scraping, Website Data Scraping, Artificial Intelligence (AI), Minimum Viable Product (MVP), Startups, Generative Artificial Intelligence (GenAI), checkoutchamp, Shopify SEO
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