Cesar is available for hire
Hire CesarCesar Enrique Diaz
Verified Expert in Engineering
Full-stack Developer
Location
Santa Fe, Santa Fe Province, Argentina
Toptal Member Since
November 15, 2012
Cesar is a seasoned web developer with extensive experience in Linux, PHP, and Rails. He loves incorporating new technologies into his work to create elegant solutions. Cesar especially enjoys working on high-traffic applications such as social network-based sites.
Portfolio
Campus Crusade for Christ, Inc. - GodTools
Ruby on Rails (RoR), API Development, PostgreSQL, HTTPS...
The Service and Connection Company
Ruby on Rails (RoR), Ruby, Tailwind CSS, HTML, CSS, Turbo, Stimulus, Devise...
Gartner - Digital Markets Engineering - Capitalizable
Ruby, Ruby on Rails (RoR), Python, Elasticsearch, Oracle, SQL, Google AdWords...
Experience
Availability
Part-time
Preferred Environment
Git, Sublime Text, Ubuntu, Linux
The most amazing...
...software I've coded was an app that worked as a versioning system for cartography maps. The app also copied map files from clients to a main server.
Work Experience
API Engineer
2023 - 2023
Campus Crusade for Christ, Inc. - GodTools
- Demonstrated expertise in Ruby on Rails (RoR) development, utilizing RoR 6, Postgres as the primary database, and Sidekiq for background job processing.
- Played a pivotal role in the development of new API endpoints, enhancing the system's capabilities for data retrieval and processing.
- Collaborated closely with teammates to identify and resolve technical issues, ensuring seamless integration of new features into the API.
- Utilized RSpec to ensure the reliability and quality of the software I developed by writing comprehensive test suites. One of my key strengths lies in my mastery of RSpec for testing.
Technologies: Ruby on Rails (RoR), API Development, PostgreSQL, HTTPS, Amazon Web Services (AWS), REST APIs, APIs, Back-end, Ruby, Ruby on Rails API
Senior Front-end/Full-stack RoR Developer
2022 - 2023
The Service and Connection Company
- Added support for checkout products from the site using the ChargeBee platform as a payment gateway. The process was made from scratch by researching and applying it to the app.
- Implemented authorization policies for visibility and accessibility to products offered on-site from scratch. There were implemented strategies through service calls and well tested with test specs in all the workflow.
- Utilized webhooks strategies to get info from ChargeBee about subscription status. Added tests to cover all the checking for subscriptions, renewal, cancellation, expiration, etc.
- Enhanced the front-end side to cover some needs like the process of visibility and accessibility checking policies or subscriptions.
Technologies: Ruby on Rails (RoR), Ruby, Tailwind CSS, HTML, CSS, Turbo, Stimulus, Devise, Pundit, jQuery, Ruby on Rails 7, Back-end Development, Payment APIs, BrainTree, Payment Gateways, Braintree API
Full-stack RoR and React Developer
2021 - 2022
Gartner - Digital Markets Engineering - Capitalizable
- Migrated Ruby on Rails software working with Google Ads.
- Worked with different RoR apps, fixing bugs and adding new features.
- Built SQL scripts to run against Oracle databases.
- Implemented tests and fixed bugs for legacy Python applications.
Technologies: Ruby, Ruby on Rails (RoR), Python, Elasticsearch, Oracle, SQL, Google AdWords, Google AdWords Scripts, AdWords API, Testing, RSpec, GitHub, Jenkins, Slack, Jira, Ubuntu Linux, Upgrades
Senior Full-stack Developer
2021 - 2021
Getaway
- Applied work on the admin app side back end, adding new features and modifying existing legacy features.
- Worked with front end by adapting new features with JavaScript using the Stimulus framework.
- Applied RSpec tests for the back end and combined with Capybara gem for acceptance front-end tests.
Technologies: Ruby, Ruby on Rails (RoR), RSpec, Heroku, PostgreSQL, Stimulus, Capybara, Travis CI, Jira, Front-end, SQL, Ubuntu Linux, HTML5
Senior Full-stack Developer
2020 - 2021
Tecstone Granite USA, Ltd.
- Built cron jobs where the goal was to process business movements.
- Developed the front end with React and Redux to accomplish different pages for the back-end control of the business.
- Created reports where the response should be a CSV file, like returning a collection of all the retailers' shipments.
Technologies: Full-stack, React, Ruby, Ruby on Rails API, Ruby on Rails (RoR), Redux, MySQL, RSpec, SQL, Sidekiq, Spree, Ubuntu Linux, HTML5
Senior Ruby on Rails Developer
2020 - 2021
Growth Constant
- Integrated the Strava API into the Ruby on Rails v.6 application, getting segments and segment efforts' information from races.
- Added testing with RSpec using the cassette strategy for taking information (answers) from Strava.
- Added a customized configuration to the administration side of the app, simplifying its development by using a gem-like rails_admin.
- Created user roles levels in the application for taking control of the front-end and back-end permissions using Pundit.
- Worked on the front-end side using Semantic UI and Haml as layout creators for the template.
Technologies: Semantic UI, Haml, Service, Docker, API Integration, APIs, RSpec, Ruby on Rails (RoR), Ruby, PostgreSQL, Back-end, Ubuntu Linux, HTTPS
Senior Ruby on Rails API Developer
2020 - 2021
MakerMonster
- Built an API in the RoR v.6 application to be consumed from mobile apps.
- Implemented TDD methodology from the very beginning to ensure code was covering expectations and to allow later code refactoring, making it more efficient, with better performance, and more understandable and clear to read.
- Implemented an admin front-end configuration for new modules just using rails_admin gem to make it available for admin role users to manage new modules from the web access side.
- Deployed on the Heroku server after every newly built module was ready to use.
- Implemented an app service for pushing notifications data to a Firebase cloud database.
Technologies: Bitbucket, Git, Heroku, Firebase, PostgreSQL, Testing, RSpec, Test-driven Development (TDD), Ruby on Rails API, Ruby on Rails (RoR), Ruby, Back-end, SQL, Ubuntu Linux, REST APIs, API Development, HTTPS
Ruby On Rails Developer
2019 - 2020
Building Intelligence
- Worked on front-end CSS styles to fix the non-looking-good views with Bootstrap.
- Added i18n translation from English to Spanish in two different apps from this company. Adapted regular View and JavaScript Angular views with i18n translation from English to Spanish.
- Set up Vagrant virtual machine environments for working with old RoR and Ruby versions, like in this case where RoR was the 2nd version in one project and 4th in the other.
Technologies: Views, Bootstrap, i18n, Vagrant, Ruby on Rails 3, Ruby on Rails 4, Ruby on Rails (RoR), Ruby, Ubuntu Linux, CSS
Web Developer
2019 - 2019
FoodSpace
- Fixed bugs in back end mainly related to bad MVC patterns and bad Active Record implementation. Supported adding new features in the back and front end.
- Built an API from scratch. Implemented TDD with RSpec and Swagger for API testing and documentation.
- Set up the Heroku staging server with the PostgreSQL database.
Technologies: Trello, APIs, GitHub, Git, Test-driven Development (TDD), Swagger, RSpec, Heroku, jQuery, JavaScript, PostgreSQL, Ruby on Rails (RoR), Ruby, Back-end, SQL, Ubuntu Linux, CSS, REST APIs, API Development
Rails Web Developer
2018 - 2019
New Ventures West
- Fixed pre-existing bugs, mainly on back-end side for a RoR 6 app.
- Supported the addition of new features, such as uploading content to Amazon S3.
- Connected the app and different 3rd-party APIs like Formstack and WordPress.
- Set up a staging server environment using Heroku .
Technologies: Trello, APIs, Bitbucket, Git, Amazon S3 (AWS S3), Heroku, jQuery, JavaScript, PostgreSQL, Ruby on Rails (RoR), Ruby, Back-end, SQL, Ubuntu Linux, Amazon Web Services (AWS), Upgrades, Databases
Web Developer
2017 - 2017
Logan
- Developed in Ruby/RoR to maintain relatively new apps. There were four apps for different purposes: some were version 4 and version 5.
- Built PostgreSQL- and MongoDB-based databases. Used Amazon S3 for file storage (mainly images, with some PDFs). Built front-end features in CoffeeScript.
- Deployed to Heroku servers. I had to configure my local environment to work with it, do database backups, and restore backups from the production server to stage server databases, among other things.
Technologies: Heroku, Amazon S3 (AWS S3), MongoDB, PostgreSQL, Ruby on Rails (RoR), JavaScript, Back-end, SQL, NoSQL, Ubuntu Linux
Ruby Web Developer
2014 - 2015
Hashdog
- Worked on Ruby on Rails, fixing different applications/bugs. Added RSpec tests to some new features.
- Worked on jQuery and CoffeeScript code. Implemented Twitter Bootstrap.
- Worked on an eCommerce Spree app, adding features that helped show clients the front-end information based on the stock in the store.
Technologies: Amazon S3 (AWS S3), Heroku, CSS, jQuery, CoffeeScript, Haml, MySQL, PostgreSQL, Ruby on Rails (RoR), Ruby, Back-end, SQL, Spree, Ubuntu Linux, REST APIs, API Development
Ruby Web Developer
2014 - 2014
Restorando
- Upgraded an existent Sinatra web app where I had to rewrite almost 60% to 70% of the base code.
- Replaced the external service with internal Ruby tools.
- Worked on different front-end small changes applying new styles provided by web designers.
- Added new test cases for changes or new Ruby code implemented.
Technologies: CoffeeScript, RSpec, MySQL, Ruby on Rails (RoR), Ruby, Back-end, SQL, Ubuntu Linux
Ruby Developer
2013 - 2014
Mediyak, LLC
- Refactored work on main Ruby libraries to order, clean, and fix them.
- Migrated the app from Ruby on Rails version 2.3.8 to 3.2.17.
- Updated the Google Data Calendar version under the leader team guide.
- Migrated the front end to Twitter Bootstrap responsive design.
Technologies: jQuery, Bootstrap, Ruby on Rails (RoR), Ruby, Back-end, SQL, Ubuntu Linux
Software Developer
2012 - 2012
Inaka
- Worked as a freelance developer for a company based in Buenos Aires.
- Created Whispers, an app to share images taken by smart phones.
- Developed the back end of the app, in which administrators verify that loaded images are correctly formatted.
- Wrote the application using Ruby on Rails 3, Riak DB, and jQuery JavaScript libraries.
- Worked on another app involving using a CouchDB database and improving software that shares messages related to MTV series episodes on Facebook.
- Built EnglishGetIt and BuenoEntonces, two sites that teach the English and Spanish languages. The apps were created on RefineryCMS using MySQL as an RDBMS.
- Adapted the original design to incorporate features such as subscription through Facebook and data extraction from CSV files.
Technologies: MySQL, CouchDB, Riak, Ruby on Rails (RoR), Back-end, SQL, Ubuntu Linux
Software Developer
2011 - 2011
Cogwise Solutions
- Worked as a freelance developer for a company based in Tennessee.
- Created a web app for online medical records that gives access to physicians, hospital staff, and patients.
- Allowed users to load their patient records, appointments, and keep track of medical procedures.
- Wrote the back end using Ruby on Rails 3 and jQuery, and deployed on Heroku servers.
Technologies: Back-end, Ubuntu Linux
Software Developer
2009 - 2011
A 4 Bandas SA
- Worked as a freelance developer for a company based in Buenos Aires, adding new features to pre-existing projects.
- Wrote features for projects such as Fotoblog (a social network), Talento Argentino, and Listas (both web applications).
- Updated Fotoblog from the first version to a second version, adding video sharing tools, functionality allowing users to make friend groups, and a Facebook wall-type feature. The app was developed using Ruby on Rails 2.3, jQuery, and MySQL DB.
- Added back-end administrator tools to Listas, a platform to share user generated lists of items that also allows users to vote, rank, and share lists. Also worked on the front end to make the design compatible with the new features.
- Developed using Ruby on Rails 2.3 at first, and then later migrating to Ruby on Rails 3. Also used jQuery MySQL in the second version.
- Added front-end and back-end tools to Talento Argentino, an application that allows people to follow popular Argentinian TV programs. The tools allowed users to load videos and administrators to approve the videos.
- Wrote the app in Ruby on Rails 3, using jQuery and MySQL.
Technologies: Git, jQuery, MySQL, Ruby on Rails (RoR), Back-end, Ubuntu Linux, CSS, HTTPS, Upgrades
Software Developer
2008 - 2011
Facultad de Ciencias Económicas
- Developed intranet apps using Ruby on Rails and coding in PHP. Used PostgreSQL and SQLite as databases. Coded in the Debian GNU/Linux environments.
- Built an intranet system to control and offer internships at Ciencias Economicas College.
- Allowed each user student to upload their CV. Teachers could view over four thousand student applications and communicate with prospective interns.
- Created a web application to organize hardware inventory in a range of locations, including factories, education buildings, and personal corporations.
- Built an intranet system for classroom booking that could also keep track of available classrooms at any given time.
Technologies: PostgreSQL, Ruby on Rails (RoR), Back-end, Debian Linux
Software Developer
2006 - 2008
Universidad Nacional del Litoral
- Created an internal web application to check the hours worked by teachers for college institutions. The system could check the start and finish times of classes and report the amount of hours worked by a teacher per month.
- Worked to build a web application for the control of a sports campus. Refactored code and implemented view tests for the project using SimpleTest with PHP.
- Helped develop a web application used to make polls for the institution. Created the statistics module which was used to generate XLS files and graphic reports.
Technologies: PostgreSQL, Debian Linux, PHP, MySQL
Software Developer
2004 - 2006
Instituto Provincial de Estadisticas y Censos
- Developed stand-alone software using Visual Basic 6.0 and Access 97 to format files for cartographic maps.
- Contributed to the software, which was used as a version control of digital map files. Specifically, it functioned to copy, control, and version files on client machines, employee PCs, and the file hosting server.
- Created an admin section to control which users were allowed to work on maps and a client machine section to control which PC clients were allowed to manipulate certain files.
- Developed a separate, small application using PHP and MySQL to make keep track of people working for the institution in 2006.
Technologies: Microsoft Access, Visual Basic
Software Developer
2003 - 2004
Infosoft Studios
- Worked on web development of a back-end app for a college social network using PHP and MySQL.
- Wrote the back end of a website to allow administrators to easily upload content.
Technologies: MySQL
Experience
Rails 5 API with a React/Redux UI
Web form where the user (a physician) enters as input patient information and a list of ingredients with associated amounts, and receives as output a PDF with the patient information and ingredients.
Whisper
http://whisper.shAn app used to check pictures uploaded to a server from smartphone apps that we also developed. I built the login, the list of images to check, and a user list that admins could manage.
MakerMonster
For this project, the intention was to build an API in Ruby on Rails 6 using a TDD methodology from the very beginning to complete every task assigned by making expectations pass tests. As an RoR developer, and besides the API work, I implemented admin front-end configuration for new modules using RubyGem. The project was deployed to Heroku servers. Also, a service for pushing data to Firebase databases was implemented. With tests covering almost all API endpoints, it was a good option to refactor code for better performance and comply with Ruby's good practices.
Skills
Languages
Ruby, CSS, SQL, JavaScript, HTML5, Visual Basic, CoffeeScript, Haml, SCSS, Python, HTML, PHP, GraphQL, TypeScript
Frameworks
Sinatra, Ruby on Rails (RoR), Bootstrap, Swagger, Ruby on Rails 4, Ruby on Rails 3, Redux, Stimulus, Capybara, Tailwind CSS
Other
Back-end, Back-end Development, HTTPS, Payment APIs, BrainTree, Payment Gateways, Upgrades, APIs, i18n, Views, API Integration, Service, Semantic UI, Computer Engineering, Spree Commerce, Full-stack, Front-end, Google AdWords Scripts, Ruby on Rails 7, CI/CD Pipelines
Libraries/APIs
Ruby on Rails API, Sidekiq, Google API, Facebook API, jQuery, REST APIs, API Development, Braintree API, React, Google AdWords, AdWords API, Devise, Pundit, Node.js
Tools
Vagrant, Git, Emacs, Cucumber, Capistrano, Microsoft Access, Sublime Text, RSpec, Bitbucket, Trello, GitHub, Spree, Chrome Developer Tools, Vim Text Editor, Basecamp, Travis CI, Jira, Jenkins, Slack, Turbo, Docker Compose
Paradigms
Functional Programming, Agile Software Development, Test-driven Development (TDD), Testing, Behavior-driven Development (BDD)
Platforms
Ubuntu Linux, Linux, Amazon Web Services (AWS), Docker, Firebase, Heroku, Ubuntu, Debian Linux, Oracle
Storage
SQLite, PostgreSQL, MySQL, Databases, Amazon S3 (AWS S3), MongoDB, CouchDB, Riak, NoSQL, Elasticsearch
Education
1997 - 2003
Bachelor of Technology Degree in Computer Engineering
Facultad de Ciencias Hidricas - Universidad Nacional del Litoral - Santa Fe, Argentina
Certifications
DECEMBER 2023 - PRESENT
Understanding TypeScript
Udemy
OCTOBER 2023 - PRESENT
NodeJS - The Complete Guide (MVC, REST APIs, GraphQL, Deno)
Udemy
JUNE 2020 - PRESENT
Docker for the Absolute Beginner - Hands On - DevOps
KodeKloud via Udemy
FEBRUARY 2019 - PRESENT
The Complete React Developer Course (w/Hooks and Redux)
Udemy
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