Paulo Castro, Developer in Brisbane, Queensland, Australia
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Paulo Castro

Verified Expert  in Engineering

Software Developer

Brisbane, Queensland, Australia
Toptal Member Since
April 4, 2016

Paulo has over 20 years of professional IT experience and has worked for the most important IT vendors and companies in Latin America, the US, and Australia, always with outstanding results. His extensive background in technologies such as Ruby and Rails, PHP, .NET (C# and VB.NET), and Java has prepared him to design and architect both intricate standalone applications and complex multi-platform distributed and cloud systems.


Current Employement
Python, Amazon Web Services (AWS), PostgreSQL, Amazon RDS, Amazon Aurora, Java...
Tagr Holdings
Node.js, TypeScript, Amazon Web Services (AWS), Agile Software Development...
Agile Software Development, Amazon Web Services (AWS), React, Ruby...




Preferred Environment

PHP, React, Ruby on Rails (RoR), Ruby, Python, Amazon Web Services (AWS), Node.js, Go, Java, TypeScript

The most amazing...

...thing I've built is Vetwork, an SaaS platform for veterinary practice management.

Work Experience

Senior Software Engineer

2023 - PRESENT
Current Employement
  • Maintained and improved a set of web services built on top of AWS APIs to manage the whole company database fleet.
  • Delivered a key project related to the company's OKR on time, leading a team of three people.
  • Re-designed the agile management process for the whole team of 25 people.
Technologies: Python, Amazon Web Services (AWS), PostgreSQL, Amazon RDS, Amazon Aurora, Java, Kotlin, SQL, Agile Software Development, Amazon S3 (AWS S3), Ubuntu, Node.js, AWS Cloud Architecture, HTML, Refactoring, Database Design


2022 - 2023
Tagr Holdings
  • Built the team from the ground up as the first hiring of the technology team. Within the first five months, I was responsible for leading two senior developers to rebuild the entire platform.
  • Rolled out a completely new platform in June 2022, leveraging modern standards and technologies. The legacy product was originally built using a monolithic architecture and outdated technologies.
  • Designed, planned, and implemented a microservices architecture on top of serverless technologies with a focus on scalability, high availability, and security.
  • Created an integration layer that allows us to integrate with new point of sales systems and payment gateways in a matter of a few weeks.
  • Worked on a platform that was created with the Infrastructure as Code (IaC) approach, which allows its complete provisioning in minutes.
Technologies: Node.js, TypeScript, Amazon Web Services (AWS), Agile Software Development, PostgreSQL, Amazon Aurora, React, Stripe, Shopify API, APIs, SDKs, Redis, AWS Lambda, Amazon DynamoDB, Linux, SQL, JavaScript, Amazon S3 (AWS S3), Google API, Mobile Development, Ubuntu, AWS Cloud Architecture, GraphQL, HTML, Full-stack, Refactoring, Database Design

Senior Full-stack Developer

2017 - 2022
  • Designed, architected, and developed new features and improved the existing ones.
  • Worked closely with key partners to integrate the platform with third-party solutions like Salesforce, Salesforce Marketing Cloud, and customer legacy systems.
  • Oversaw the platform's infrastructure and security management.
Technologies: Agile Software Development, Amazon Web Services (AWS), React, Ruby, Ruby on Rails (RoR), AWS Lambda, Node.js, Go, PostgreSQL, Linux, Python 3, TypeScript, SQL, JavaScript, Amazon S3 (AWS S3), Google API, Ubuntu, AWS Cloud Architecture, GraphQL, HTML, Full-stack, Refactoring, Database Design

Senior Full-stack Ruby on Rails Developer

2008 - 2017
  • Developed new features (screens and databases) for Vetwork, a web-based veterinary solution that manages all the key areas of a veterinary practice like clients, patients, scheduling and appointment booking, invoicing, exams, clinical records, etc.
  • Designed, deployed, and maintained all AWS infrastructure to host the platform.
  • Led and coached a team of three developers. Managed sprints and reviewed code.
Technologies: Git, Amazon S3 (AWS S3), Ubuntu, SQLite, MySQL, HTML5, jQuery, Ruby on Rails (RoR), Ruby, Linux, SQL, JavaScript, Agile Software Development, Google API, AWS Cloud Architecture, HTML, Full-stack, Database Design

Full-stack RoR Senior Developer

2015 - 2015
NPGL (via Toptal)
  • Developed in Ruby on Rails for a public and internal system.
  • Developed in Node.js to support matches during 2015 season.
  • Provided Heroku environment support.
  • Developed and supported using RoR and AngularJS.
  • Developed and supported GridTV using PHP and MySQL.
Technologies: Amazon Web Services (AWS), Heroku, PostgreSQL, AngularJS, Ruby on Rails (RoR), Ruby, Linux, SQL, JavaScript, Agile Software Development, Amazon S3 (AWS S3), Node.js, HTML, Full-stack, Database Design

Tiger Team

2010 - 2015
  • Supported Latin American customers.
  • Worked with entire IBM middleware stack.
Technologies: Middleware, Microsoft SQL Server

Senior RoR Developer

2011 - 2011
LeadtrackPro (via Toptal)
  • Optimized and migrated Leadtrackpro, a system to manage property grant tracking and reports originally built on ColdFusion, to Ruby On Rails.
Technologies: Git, SQLite, jQuery, Ruby on Rails (RoR), Ruby, MySQL, Linux, SQL, JavaScript, HTML, Full-stack, Database Design


2007 - 2010
  • Provided specialized architectural expertise in Fusion middleware.
Technologies: Oracle Fusion Middleware


2006 - 2007
Altran Group
  • Provided services as an SOA specialist.
Technologies: Service-oriented Architecture (SOA), TIBCO, webMethods, SQL, Microsoft SQL Server, Database Design

Senior Developer

2002 - 2005
  • Developed a new capture platform for Intervalor, a service consulting for financial companies. The platform was for credit requests responsible for managing the entire request lifecycle through credit delivery.
  • Built a new advocacy office management system responsible for running contentious charges.
Technologies: Microsoft SQL Server, Web Services, ASP.NET, C#, Microsoft Visual Studio, SQL, JavaScript, HTML, Full-stack, Database Design


Project stack: Ruby On Rails, jQuery, HTML5/CSS, MySQL, SQLite, Ubuntu, Amazon Web Services (EC2, RDS, EBS, S3) and Git


Project stack: RoR, AngularJS, Node.js, PHP, PostgreSQL, MySQL, Heroku, AWS


Project stack: RoR, MySQL, Angular.JS, AWS

Vegan Snack Packs

Project stack: Ruby On Rails, MySQL, Spree Commerce, Wombat, Amazon Web Services

Cricket Victoria (Australia)
Project stack: CakePHP, MySQL, jQuery

Site Done Right
Migration from old Ruby On Rails to PHP and Smarty technologies.
2004 - 2008

Bachelor's Degree in Information Technology

FASP - Brazil


Offensive Security Exploit Developer Certification

Offensive Security


Offensive Security Certified Professional

Offensive Security


Certified Associate in Python Programming - PCAP

Python Institute


Certified Information Systems Security Professional



Oracle Certified Associate, Java SE 8 Programmer



AWS Certified Solutions Architect Professional

Amazon Web Services


React, Google API, jQuery Mobile, jQuery UI, jQuery, Node.js, Stripe, Stripe API, API Development, Shopify API


Git, Adobe Photoshop, Chef, Basecamp, Microsoft Visual Studio, Vagrant, GitHub, GitLab, Bitbucket


Ruby on Rails (RoR), CakePHP, Bootstrap, ASP.NET, AngularJS, PhoneGap, Kendo UI, Telerik Kendo UI, React Native


HTML5, JavaScript, CSS3, C#, Ruby, SQL, PHP, Python, Python 3, GraphQL, HTML, TypeScript, XML, Go, Java 8, Java, Kotlin


Service-oriented Architecture (SOA), Agile Software Development, Object-oriented Programming (OOP), Event-driven Programming, Penetration Testing, Agile, Refactoring, Database Design, Mobile Development


Ubuntu, Heroku, WordPress, Amazon Web Services (AWS), Linux, AWS Lambda, webMethods, Telerik


SQLite, PostgreSQL, Amazon S3 (AWS S3), MySQL, Microsoft SQL Server, Amazon Aurora, Redis, Amazon DynamoDB


Software Development, Web Services, AWS Cloud Architecture, Web Security, Application Security, Information Security, Full-stack, APIs, Web Development, PayPal, API Integration, Cordova, TIBCO, Oracle Fusion Middleware, SDKs, Amazon RDS

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