Caio is available for hire
Hire CaioCaio Kinzel Filho
Verified Expert in Engineering
JavaScript Developer
Sunshine Coast, Queensland, Australia
Toptal member since February 23, 2016
Bio
Caio is a principal engineer with nearly 20 years of experience building and scaling fintechs and startups. A ThoughtWorks alumnus, he has led engineering teams and architected payment systems for companies like Slice, Flex, and InDebted. Caio specializes in event-driven systems, orchestration, architecture, and payment solutions.
Portfolio
Slice
TypeScript, Amazon Web Services (AWS), Temporal Cloud, Stripe, Pulumi, Nx...
Forget Me Not
TypeScript, Amazon Web Services (AWS), Serverless, Pulumi, Event Sourcing...
Flex
TypeScript, Event Sourcing, Amazon Web Services (AWS), Serverless, React Native...
Experience
- Event Sourcing - 10 years
- TypeScript - 5 years
- Pulumi - 4 years
- Amazon Web Services (AWS) - 3 years
- Temporal Cloud - 3 years
Work Experience
Principal Engineer
2024 - 2026
Slice
- Changed how the company processes payments, saving us AUD 7+ million annually.
- Set up platform and data platform infrastructure, as well as initial data products, data analytics, and reports.
- Implemented event-based alerts of Airline Schedule Changes and processing rules.
Technologies: TypeScript, Amazon Web Services (AWS), Temporal Cloud, Stripe, Pulumi, Nx, Event Sourcing, Kubernetes, BigQuery, Airbyte, Amazon DynamoDB, Metabase, Tableau, Datadog, OpenTelemetry, PostgreSQL, APIs, Cloud Architecture, ETL, Large Language Models (LLMs), Python, Agentic AI, Orchestration, Workflow, GitHub
Head of Engineering
2022 - 2024
Forget Me Not
- Grew the team from two to eight engineers as a hands-on head of engineering.
- Improved build time from 45 minutes to 30 seconds, which was absolutely vital for engineering scaling.
- Introduced new ways to communicate with stakeholders, building trust with the engineering team while improving delivery.
Technologies: TypeScript, Amazon Web Services (AWS), Serverless, Pulumi, Event Sourcing, Google BigQuery, PostgreSQL, APIs, Cloud Architecture, ETL, Large Language Models (LLMs), Agentic AI, Orchestration, Workflow, GitHub, AWS Step Functions
Lead Front-end Engineer
2020 - 2022
Flex
- Developed new customer onboarding flows in new mobile apps.
- Managed bill payments and rent payment portal integrations.
- Increased app store rating from 3.2 to 4.5 within a couple of months.
Technologies: TypeScript, Event Sourcing, Amazon Web Services (AWS), Serverless, React Native, Mixpanel, BigQuery, Firebase, Cloud Firestore, Zendesk, Plaid, Analytics, APIs, Cloud Architecture, ETL, Orchestration, Workflow, GitHub
Senior Software Engineer
2019 - 2020
InDebted
- Engineered solutions across systems such as a money-movement infrastructure.
- Established style guides in the web app and set up a storybook.
- Implemented secure, self-healing, highly scalable serverless microservices.
Technologies: Amazon Web Services (AWS), Stripe, Material UI, React, Event Sourcing, Amazon DynamoDB, Serverless, Go, PostgreSQL, APIs, Cloud Architecture, Orchestration, Workflow, GitHub
Senior Full-stack Developer
2019 - 2019
SelectQuote (via Toptal)
- Added functionality to C# and Node.js projects.
- Created A/B testing variants of customer-facing pages.
- Migrated the system to a new platform.
- Improved the performance of multiple client-facing pages through code-splitting, sprites, and so on.
Technologies: SQL, Web API, C#, Node.js, GitHub
Lead Front-end Engineer
2018 - 2018
Run The Call
- Restructured the app and migrated it from Angular to React.
- Built an app-wide component library.
- Created JavaScript-side style guides.
- Fixed defects and got the app ready for production.
Technologies: Styled-components, Redux-Saga, Redux, React, PostgreSQL, Cloud Architecture, GitHub
Technical Lead
2018 - 2018
Scribe Intelligence (via Toptal)
- Architected and implemented a back-end migration to event sourcing.
- Redesigned the React front end.
- Improved the performance of the application which was rendering large datasets.
- Mentored other developers.
Technologies: Amazon Web Services (AWS), Streaming, Event Sourcing, React, Node.js, Cloud Architecture
Chatbot Developer
2017 - 2017
Cryptocurrency Chatbot Startup
- Created a chatbot prototype for cryptocurrency trading; used the tools for classification and natural language processing.
- Implemented chatbot memory for session support.
- Created a single-page application (SPA) in React for interacting with the chatbot.
Technologies: Redux, React, NATURAL, Natural Language Processing (NLP), Generative Pre-trained Transformers (GPT), Chatbots, Node.js, GitHub
Full-stack Developer
2017 - 2017
Ethereum Marketplace Startup
- Developed Ethereum smart contracts for a digital marketplace's payments and escrow.
- Built a back end in Node.js, MongoDB, and GraphQL.
- Created a front end in React to integrate with GraphQL using Apollo.
- Implemented the authentication system with Auth0 in React.
Technologies: MongoDB, Apollo, GraphQL, Solidity, Ethereum Smart Contracts, Redux-Saga, Redux, React, Node.js, GitHub
Senior Front-end Developer
2017 - 2017
Redizoo (via Toptal)
- Created the front end of a React app to integrate with a C# Web API back end.
Technologies: Web API, C#, Styled-components, Redux, React, GitHub
Back-end Engineer
2017 - 2017
Scribevo (via Toptal)
- Optimized the performance of a streaming back-end for speech recognition by 20x.
- Built the foundation for a test-driven development workflow.
- Decreased the operational costs of the application pipeline by improving third-party integration points.
Technologies: Amazon Web Services (AWS), IBM Watson, Docker, PostgreSQL, Streaming, Node.js
React Native Lead Developer
2017 - 2017
Clinova
- Led a small team in the development of a React Native app.
- Designed and architected the application from specs to deployment.
- Set up tests and deployment infrastructure.
- Prepared the application for internationalization and copywriting.
Technologies: Express.js, Node.js, MongoDB, Fastlane, Android, iOS, Styled-components, Redux, React Native, GitHub
Senior React Developer
2017 - 2017
University at Buffalo—SUNY (via Toptal)
- Developed a React application for music notation editing.
- Created a back-end application to handle simple APIs.
Technologies: Node.js, MongoDB, VexFlow, Enzyme, Reselect, Immutable.js, Redux-Saga, Redux, React, GitHub
Front-end Developer
2017 - 2017
Run The Call (via Toptal)
- Set up continuous integration.
- Built the foundation for unit tests and automated acceptance tests.
- Prepared the app for initial release.
- Stabilized and added features to the front-end.
Technologies: Node.js, Google Cloud, Kubernetes, Docker, GraphQL, Angular Material, AngularJS, JavaScript, GitHub
Front-end Developer
2016 - 2016
Must Win | Zenefits (via Toptal)
- Added React/Redux to the existing application.
- Implemented responsive web views using React.js and Sass under a tight deadline.
- Maintained and extended the existing Django framework and models.
Technologies: Sass, Responsive Design, Django, Python, Redux, React, GitHub
JavaScript Engineer
2016 - 2016
Must Win (via Toptal)
- Worked as a JavaScript front-end developer on an AngularJS codebase.
- Created a data metrics pipeline using InfluxDB, Docker, Grafana, and Kafka.
- Set up a unit testing framework for the Angular code base.
Technologies: User Interface (UI), D3.js, Grunt, ESLint, Restangular, Apache Kafka, InfluxDB, Docker, Grafana, AngularJS, JavaScript, Cloud Architecture, GitHub
Lead Consultant (Web Developer)
2014 - 2015
Managed Cloud Computing Provider (via ThoughtWorks)
- Implemented continuous delivery with multiple deploys a day.
- Created a dashboard for managing cloud servers, databases, and so on.
- Developed a module for the management of automatic scaling of cloud servers and nodes.
- Wrote a single-page application with a company-rolled layout framework.
- Created a pipeline with thousands of tests backing the deployment process from commit to production deploy.
Technologies: React, Node.js, Cassandra, Google Closure, JavaScript, Cloud Architecture, Python
Technical Lead
2013 - 2014
Johannesburg Stock Exchange (via ThoughtWorks)
- Introduced and established agile processes to multiple teams.
- Provided guidance for the client's technical leaders on how to incorporate processes and tools.
- Built an internal tool to remove manual workload for an important department.
- Trained client developers and testers on automated functional tests.
- Helped the business with project inception and minimal viable product specifications.
Technologies: AngularJS, JavaScript, NHibernate, Microsoft SQL Server, ASP.NET MVC, C#
Senior Web Developer
2012 - 2013
Vision Critical (via ThoughtWorks)
- Built a platform for customized survey creation.
- Created a continuous delivery pipeline.
- Implemented a polyglot persistence on MongoDB and SQL Server.
- Worked on a RESTful API for back-end services.
- Designed a functional testing suite to be used by developers and testers.
Technologies: MongoDB, Microsoft SQL Server, JavaScript, ASP.NET MVC, C#
Technical Lead
2011 - 2012
Measured Progress (via ThoughtWorks)
- Built a rich client web application to manage custom student assessments.
- Introduced continuous integration, testing, and Agile processes.
- Developed a testing framework for a higher integration between business analysts and developers.
- Worked on a rich WYSIWYG editor with custom functions and math formulas.
- Designed the application from iteration 0 to a succesful platform.
Technologies: Microsoft SQL Server, JavaScript, NHibernate, ASP.NET MVC, C#
Senior Web Developer
2010 - 2010
World’s Largest Apparel Retailer (via ThoughtWorks)
- Created a large-scale enterprise web app.
- Worked with distributed teams on multiple continents.
- Utilized Agile and Scrum methodologies.
- Developed a plan to reduce technical debt.
Technologies: XSLT, XML, Spring, Java
Senior Web Developer
2009 - 2010
TOTVS
- Worked on a large enterprise multi-tenant software.
- Built hospital management web modules.
- Integrated with existing web services and APIs.
- Created workflows with WF and integrated it with the existing software.
Technologies: Oracle, Microsoft SQL Server, ASP.NET, C#, APIs
Lead Developer
2007 - 2009
Aguiar Express
- Gained full project life-cycle experience.
- Migrated VB6 to .NET technologies.
- Led and managed team members into Agile practices.
- Created a logistics and scheduling app to handle a multi-location store and delivery system.
- Developed the company's intranet.
- Developed a POS system in direct contact with business experts.
Technologies: Microsoft SQL Server, Firebird, ASP.NET, C#, Visual Basic
Freelance Web Developer
2007 - 2008
Conceito Web
- Developed a multitier and multitenant eCommerce application.
- Responsible for the system's architecture.
- Created a web application that could host several different "skins."
Technologies: Microsoft SQL Server, ASP.NET, VB.NET
Windows Developer
2005 - 2006
Zeta Informática
- Developed an in-house ERP system.
- Helped with source-control metrics.
Technologies: Topspeed, Clarion
Project History
Chengeta Wildlife Website
Developed this website for an NGO working on anti-poaching training in African countries.
Education
2003 - 2008
Bachelor's Degree in Engineering (Digital System Engineering)
Universidade Estadual do Rio Grande do Sul - Guaiba, Brazil
Skills
Libraries/APIs
Sinon.JS, Lodash, jQuery, React, Node.js, Google Closure, Restangular, D3.js, Immutable.js, Reselect, Web API, Stripe, Redux-Saga
Tools
Atom, Mocha, Microsoft Visual Studio, Sublime Text, GitHub, Grafana, Grunt, Fastlane, IBM Watson, Claude, BigQuery, Plaid, Nx, Tableau, AWS Step Functions
Languages
JavaScript, C#, TypeScript, HTML5, HTML, Sass, SCSS, CSS3, SQL, Visual Basic, VB.NET, Java, XML, XSLT, Clarion, Topspeed, Python, GraphQL, Solidity, NATURAL, Go, Visual Basic 6 (VB6), F#
Frameworks
ASP.NET MVC, React Native, Express.js, NHibernate, AngularJS, ASP.NET, Spring, Django, Angular Material, Material UI, ASP.NET Web API, Redux, Nancy, Rx, Bootstrap 3
Paradigms
Continuous Integration (CI), Continuous Delivery (CD), Agile Software Development, Model View Controller (MVC), Test-driven Development (TDD), Event Sourcing, Unit Testing, Acceptance Testing, REST, Responsive Web Design (RWD), Functional Programming, ETL
Platforms
Amazon Web Services (AWS), Oracle, Apache Kafka, Kubernetes, iOS, Android, MacOS, Docker, WordPress, Heroku, Windows, Mixpanel, Firebase, Zendesk, Temporal Cloud, Airbyte
Storage
PostgreSQL, Firebird, MySQL, SQLite, MariaDB, Cassandra, Microsoft SQL Server, InfluxDB, Google Cloud, Amazon DynamoDB, MongoDB, Cloud Firestore, Datadog
Other
Front-end, APIs, Cloud Architecture, Orchestration, Workflow, ESLint, User Interface (UI), Responsive Design, Enzyme, VexFlow, Styled-components, Streaming, Ethereum Smart Contracts, Apollo, Chatbots, Natural Language Processing (NLP), Serverless, Single-page Applications (SPAs), VPS/VDS, User Experience (UX), Prototyping, Generative Pre-trained Transformers (GPT), Analytics, Pulumi, Google BigQuery, Metabase, OpenTelemetry, Large Language Models (LLMs), Agentic AI
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