Santiago Perez, Developer in Caracas, Venezuela
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Santiago Perez

Verified Expert  in Engineering

Full-stack Developer

Caracas, Venezuela
Toptal Member Since
March 23, 2021

Santiago is a full-stack developer with over six years of experience delivering high-quality software for clients in the United States, Mexico, and Germany. Santiago specializes in Ruby on Rails and React and enjoys transforming loose ideas and user feedback into actionable requirements and readable, well-tested code.


Ruby on Rails (RoR), Stimulus, Hotwire
React, Ruby on Rails (RoR), Python, Full-stack, Banking & Finance, Finance
Meet Edgar
Ruby on Rails (RoR), React, RSpec, Jest, Full-stack




Preferred Environment

MacOS, Git

The most amazing...

...thing I've built, as a solo developer, was a full personal finance tracking app using Ruby on Rails.

Work Experience

Full-stack Developer

2022 - PRESENT
  • Built an MVP for an accounting and invoice reconciliation service.
  • Built integrations with fiscal and banking information providers to automate invoice reconciliation.
  • Created a full system for a B2B payments wallet and applied for a Mexican IFPE license (pending).
  • Created an integration with the Mexican central bank's (Banxico) instant payments platform (SPEI) through a third-party provider.
Technologies: Ruby on Rails (RoR), Stimulus, Hotwire

Technical Lead

2021 - 2022
  • Helped grow a B2B payments app from tens to hundreds of business clients, moving in the tens of millions of USD through our rails.
  • Grew a team of three up to 10+ engineers, leading the sourcing and interviewing process.
  • Provided mentorship and architectural feedback to the team, helping implement better continuous delivery practices, on top of individual contributions to new features and improvements.
Technologies: React, Ruby on Rails (RoR), Python, Full-stack, Banking & Finance, Finance

Full-stack Developer

2020 - 2021
Meet Edgar
  • Built the back end for multi-user collaboration and several parts of the front end for the said feature.
  • Improved integrations with LinkedIn by allowing a separate connection for personal and organization accounts.
  • Improved test coverage by introducing integration tests for GraphQL endpoints and React components.
Technologies: Ruby on Rails (RoR), React, RSpec, Jest, Full-stack

Full-stack Developer

2018 - 2020
  • Added a collaboration functionality to allow multiple users to configure and manage a form.
  • Implemented file uploads to the form-endpoints using ActiveStorage and S3.
  • Integrated Slack and Google Sheets to enable syncing form submission to these services.
  • Incorporated a drag-n-drop form builder to allow non-technical users to create forms.
Technologies: Ruby on Rails (RoR), JavaScript, RSpec, Capybara, Full-stack

Full-stack Developer

2018 - 2018
  • Updated an analytics report generation tool to use a GDPR-compliant service.
  • Worked remotely as part of the team for their Berlin office.
  • Tracked and fixed bugs and minor improvements on a set of Ruby on Rails and React apps.
Technologies: Ruby on Rails (RoR), React, Full-stack

Full-stack Developer

2017 - 2017
Talent Hack
  • Developed a full MVP for a job board for the fitness industry as a solo developer.
  • Added a search-and-filtering functionality to help fitness professionals find job openings.
  • Built an interview appointment system to make it easier for managers to handle applications.
Technologies: Ruby on Rails (RoR), React, RSpec, Full-stack

Front-end Developer

2016 - 2016
  • Helped develop the front end of the web application using Angular 2 that also consumed a REST API.
  • Created an availability calendar for tour providers to configure their schedules.
  • Designed and implemented a library to simplify the consumption of the API from the front end.
Technologies: Angular, Node.js

PocketPatch is a Ruby on Rails web application for personal finance management. It allows users to connect their bank accounts through Plaid and classifies their expenses automatically using a machine learning (ML) model.

I built both the main Ruby on Rails application that interfaces with Plaid and serves the UI and a small service that hosts the ML models (ClassyMoney).

Rails by Example
A compilation of Ruby on Rails example apps that showcase small problems I've had to solve with Rails. I hope to grow it over time and eventually add more detailed explanations through a blog. So far, I have published three repositories and have code for the other three examples that I still need to clean up.


I built, for personal use, this simple calendar with a to-do list, a day planner, and a habit tracker using Ruby on Rails. It was mostly an experiment for using Hotwire and the latest tooling for Rails front-end interactions but I'm still working on improving it.


A small Flask-based service to categorize (classify) financial transactions according to a user's previous categorization. It provides an endpoint to fit a machine learning model and one to make predictions with it. It complements PocketPatch.
2013 - 2017

Engineer's Degree in Systems Engineering

Universidad Metropolitana - Caracas, Venezuela


React, Scikit-learn, Plaid API, Node.js


RSpec, Git


Ruby on Rails (RoR), Capybara, Stimulus, Flask, Angular, Jest


Ruby, JavaScript, Python

Industry Expertise

Banking & Finance


Database Design


Heroku, MacOS




Full-stack, Computer Science, Finance, Unix Shell Scripting, Hotwire

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