Jonathan Andres Garay Mendoza
Verified Expert in Engineering
Ruby Developer
Chihuahua, Mexico
Toptal member since June 16, 2014
Jonathan is a senior back-end engineer with 15 years of experience in Ruby on Rails and Elixir. He is an expert in payment systems and PostgreSQL, with deep experience in high-volume data pipelines, ETL, and performance work on large production codebases. Most recently, he has been building AI-driven data platforms that prepare complex datasets for LLM workflows. Jonathan also maintains open-source libraries in the payments space and delivers on time without cutting corners on quality.
Portfolio
Experience
- Ruby - 15 years
- Ruby on Rails (RoR) - 15 years
- PostgreSQL - 15 years
- Java - 10 years
- Elixir - 6 years
- Spring - 6 years
- React - 5 years
- Backbone.js - 2 years
Preferred Environment
MacOS, Git, Emacs, SOLID Principles, Claude Code
The most amazing...
...thing I've worked on is the development of a payment portal for a large Mexican bank.
Work Experience
Senior Software Developer
Healthkey
- Re-architected the ETL ingestion pipeline in Elixir/Phoenix, designing a more scalable and fault-tolerant data flow that improved reliability and throughput for high-volume ingestion workloads.
- Built and optimized high-performance data pipelines powering AI-intensive applications, ensuring large datasets were processed, transformed, and delivered efficiently to downstream ML consumers.
- Redesigned the data ingestion architecture by partitioning a 1TB+ monolithic PostgreSQL table into subject-specific partition tables, dramatically improving query performance and making the system easier to maintain and scale.
- Built ETL ingestion on Amazon SQS and Lambda, and contributed architecture recommendations that helped DevOps improve the PDF-processing Lambda's reliability and throughput.
Senior Full-stack Developer
FilmFreeway
- Built a legacy app, modernizing the basic testing infrastructure. We also improved user interaction capabilities to understand better how users and customers actually use the products and applications across all products and applications.
- Implemented a UTM-like tracking cookie for the marketing products.
- Oversaw the migration and launch of a major Ruby on Rails upgrade.
Software Engineer
POTLOC
- Architected and implemented high-performance ETL pipelines, significantly reducing data processing time.
- Led back-end optimization initiatives focusing on data processing and system efficiency.
- Refactored the core Ruby codebase, resulting in significant improvements in memory efficiency.
Ruby Developer
Valence Labs, Inc.
- Worked on the back end, implementing new functionalities.
- Migrated implementations from Ruby to Elixir and performed database optimizations.
- Implemented facilities to process large amounts of transactions per minute.
Senior Software Engineer
Michelada.io
- Implemented asynchronous video and data processing using Node.js.
- Developed front-end functionality using React for a hiring management platform.
- Supported and modified Spree Commerce plugins for a variety of clients.
- Created full API and iOS applications from scratch for a Trello-like startup.
Software Engineer
Stowaway Cosmetics
- Maintained the subscription workflow for Spree and ensured the overall functionality of the site. Added unit and behavior tests to enhance the project's reliability.
- Extended Spree to create custom features for the admin.
- Created a public Spree API to create a React front end for the store.
- Provided general support for the existing legacy code.
Senior Software Developer
1A Auto de Mexico
- Contributed to the new e-commerce Java-based portal.
- Created a completely new product involving an ETL and other data conversion technologies.
- Created the vendor's dedicated interface infrascructure.
- Added Ansible and Docker deployments for some projects.
- Provided general data processing and transformation of the business.
Software Developer
Crowd Interactive
- Performed as a consultant for StyleVie, a Ruby on Rails-based eCommerce platform.
- Collaborated as a consultant and Ruby on Rails back-end developer for GoPago. Migrated the architecture from Rails 2 to Rails 3. Implemented the customers' menu editor.
- Served as a consultant and Ruby on Rails back-end and front-end developer for BillFloat.
- Created an iOS client for retrospectus.com, an in-house application.
Senior Software Developer
SERLOCC
- Developed the Chihuahua local government vehicle plates registration program.
- Implemented integration with tax department POSs for the Chihuahua local government pin pad.
- Created the Chihuahua local government online tax payment system.
System Administrator
Total Automation and Controls
- Created the company ERP.
- Handled the email, file sharing, and LDAP servers.
Junior PHP Developer
Conorte Alsuper
- Supported the provider inventory page.
Skills
Libraries/APIs
REST APIs, ActiveRecord, React, Backbone.js, Stripe, Shopify API, Node.js, React DnD, Vue, jQuery, CocoaPods, Devise, Ruby on Rails API
Tools
Emacs, Claude Code, Adobe Photoshop, IDEA IDE, Zsh, Fireworks, Git, Apache Solr, Spree, Hotwire, Amazon Simple Queue Service (SQS)
Languages
Elixir, Ruby, PHP, CoffeeScript, SQL, JavaScript, Java, TypeScript, CSS, HTML, Bash, Objective-C, Erlang, Perl
Frameworks
Spring, Spring MVC, Ember.js, Ruby on Rails (RoR), Laravel, Cocoa Touch, Cocoa, Sinatra, ReactiveCocoa, Phoenix, Spring Boot, Tailwind CSS, .NET, Jakarta Server Pages (JSP), JSF, Qt, CodeIgniter, Core Data
Paradigms
MVC Design, Functional Programming, Model View Controller (MVC), Functional Reactive Programming, Service-oriented Architecture (SOA)
Platforms
Heroku, MacOS, Linux, Amazon Web Services (AWS), iOS, Docker, Percona, Oracle, Android, Windows, Ubuntu, AWS Lambda
Storage
PostgreSQL, Databases, Elasticsearch, CouchDB, MySQL, Microsoft SQL Server, PostGIS, MariaDB, Redis Cache
Other
SOLID Principles, APIs, Back-end, Full-stack Development, Deployment, Architecture, API Integration, LLM Integration, Workflow Automation, Artificial Intelligence (AI), AI Integration, LLM Agents
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