Brian Díaz, Developer in Santiago, Dominican Republic
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Brian Díaz

Verified Expert  in Engineering

Software Engineering Developer

Santiago, Dominican Republic
Toptal Member Since
September 8, 2022

Brian is an innovative developer and a problem solver. He has 8+ years of experience developing web back- and front-end services in various domains and with diverse tech stacks for startups and medium and large companies. Experienced in working with fast-moving teams and fixed deadlines, Brian is proficient in different methodologies and technologies, allowing him to learn and quickly adapt to new working environments.


Veracode Inc.
Node.js, OWASP, REST APIs, Express.js, MongoDB, SQLite, JSON Web Tokens (JWT)...
React, JavaScript, TypeScript, Node.js, Google Cloud Platform (GCP), Azure...
Potion AI, Inc
React, Node.js, Full-stack, JavaScript, SQL, Python, GraphQL, Slack, MacOS...




Preferred Environment

Slack, MacOS, Linux

The most amazing...

...project I've joined as one of the 1st engineers was involved in creating one of the top automotive startups in Brazil, which raised more than $55 million.

Work Experience

Senior Software Engineer | Content Creator

2023 - 2024
Veracode Inc.
  • Created Node.js Express Rest APIs for OWASP API Security Top 10 Course.
  • Implemented security measures outlined in the OWASP API Security Top 10 guidelines. Implemented JWT, Rate Limiters, XSS, and SQL injection security measures, among others.
  • Impressed the client with the efficiency with which these functional APIs were developed, recognizing their potential impact on the broader software engineering community.
Technologies: Node.js, OWASP, REST APIs, Express.js, MongoDB, SQLite, JSON Web Tokens (JWT), XSS Protection, SQL Injection Protection, Security

Software Engineer

2022 - 2023
  • Worked as a full-stack engineer, collaborating with clients in the US to deliver high-quality solutions.
  • Developed new features, resolved bugs, and provided ongoing maintenance for a calendar application used by a prominent TV show company in the US. Technologies utilized include React, Node.js, JavaScript, Firebase, Jest, and CircleCI.
  • Designed and implemented a secure service for sharing 3D printing resources for a medium-sized client in the US. Technologies employed include Node.js, TypeScript, NestJS, Google Cloud Platform (GCP), and JSON Web Tokens (JWT).
  • Played a vital role in the Houston team, creating a minimum viable product (MVP) for ClarityFirst, a large US-based company. Developed the application using React, TypeScript, React Query, MUI (Material UI), React Testing Library, and Lexical.
  • Led the front-end development for a major dental industry client, creating and implementing solutions using React, TypeScript, Material UI, Storybook, and React Query while transforming Figma designs into functional, responsive features.
Technologies: React, JavaScript, TypeScript, Node.js, Google Cloud Platform (GCP), Azure, Material UI, Material Design, Figma, Firebase, Jest, Storybook, React Query, REST APIs, NestJS, User Interface (UI), ECMAScript (ES6), Styled-components, React Redux, CSS, CSS3, jQuery, UI Components

Senior Full-stack Engineer

2022 - 2023
Potion AI, Inc
  • Developed new features for the AI platform using React, TypeScript, Node.js, NestJS, and GraphQL.
  • Converted Figma designs into working responsive features.
  • Fixed bugs on the back end using Node.js, NestJS, TypeScript, and GraphQL.
  • Improved the search performance by 30% by refactoring queries.
Technologies: React, Node.js, Full-stack, JavaScript, SQL, Python, GraphQL, Slack, MacOS, Chakra UI, REST APIs, Storybook, Unit Testing, Software Engineering, HTML5, ECMAScript (ES6), User Interface (UI), UI Components

Senior Front-end Engineer

2022 - 2022
OzoneAI, Inc.
  • Fixed bugs in the current platform using the Ruby on Rails framework.
  • Helped the team fix and deploy a failing application in staging and production to AWS using AWS Elastic Beanstalk, Redis, Amazon RDS, Amazon CloudFront, and Amazon EC2.
  • Added new features using React and JavaScript alongside Rails.
Technologies: JavaScript, TypeScript, React, Ruby on Rails 4, Amazon Web Services (AWS), PostgreSQL, AWS Elastic Beanstalk, Redis, Slack, MacOS, REST APIs, Storybook, Unit Testing, Software Engineering, HTML5, ECMAScript (ES6), User Interface (UI)

Software Engineer

2021 - 2022
  • Took part of the team of engineers that developed the certified refurbished admin tool as a front-end engineer, using Node.js, Express.js, React, Redux, TypeScript, JavaScript, and CSS.
  • Implemented unit tests with Jest, Enzyme, and Cypress, code coverage with Jest, and used Prettier with ESLint for code linting.
  • Maintained, added features, and fixed bugs on pages that have millions of daily views in collaboration with multiple teams.
  • Created micro frontends POCs with Webpack Module Federation and Next.js to implement in future eBay projects.
  • Implemented eBay's middleware packages for session handling and API calls in a Node.js server that runs concurrently with the front end.
  • Worked with the Venus team in implementing new components to the listing page, which has millions of views daily.
  • Collaborated with the MyEbay team in migrating legacy systems to a new architecture and redesigning my eBay pages using Marko.js, Node.js, and JavaScript.
Technologies: Node.js, JavaScript, React, Marko.js, Git, JSX, Jest, TypeScript, Express.js, ESLint, Webpack, CSS, HTML, Enzyme, Jira, Scrum, GitHub, Responsive Web Apps, Agile Software Development, SQL, Next.js, Front-end, Web Development, Slack, MacOS, NPM, Unit Testing, Software Engineering, HTML5, ECMAScript (ES6), User Interface (UI)

Software Engineer

2020 - 2021
  • Worked with a large team on the migration of a FoxPro system from a big company to a top-notch tech stack.
  • Used React, TypeScript, Redux, Sagas, Redux Observables, Less, Webpack, and Material UI in the front end.
  • Built REST APIs to handle the Node.js-based back end with NestJS, TypeScript, SQL Server, Redis, and TypeORM.
  • Created scripts that generate schema views from SQL Server into TypeORM entities.
  • Assigned as temporary tech lead for four months with an average of 92% sprint completion rate.
Technologies: Node.js, TypeScript, NestJS, React, Redux, Less, CSS, SQL Server 2015, Redis, Amazon RDS, Material UI, JSON Web Tokens (JWT), ESLint, Jest, Enzyme, Webpack, TypeORM, Bitbucket, PostgreSQL, Redux-Saga, HTML, Jira, Scrum, Git, Responsive Web Apps, Agile Software Development, SQL, Full-stack, jQuery, APIs, Front-end, Back-end, Web Development, Amazon Web Services (AWS), Slack, MacOS, Linux, Figma, Amazon S3 (AWS S3), REST APIs, Styled-components, Storybook, NPM, Unit Testing, Software Engineering, HTML5, ECMAScript (ES6), User Interface (UI), UI Components

Software Engineer

2015 - 2021
  • Started as one of the first engineers in the company that evolved into one of the major startups in Brazil and Latin America with more than $55 million raised.
  • Led the software development of numerous services and REST APIs for real-time geolocation, reporting, and mailing using Node.js, JavaScript, and TypeScript.
  • Created serverless functions for event handling with the auction platform, mailing, and financial solutions, among others.
  • Worked with notification systems using pusher, AWS Lambda, and Firebase.
  • Implemented several AWS features to manage services in the cloud, such as RDS, EC2, ECS, S3, CodePipeline, Lambda, Cognito, SES, SNS, CloudFront, and others.
Technologies: HTML, CSS, Node.js, MongoDB, TypeScript, React, JavaScript, AWS Lambda, NestJS, Koa, Express.js, Twilio API, Google Calendar API, AWS Elastic Beanstalk, Amazon Simple Notification Service (Amazon SNS), Amazon CloudFront CDN, Amazon RDS, Git, Bitbucket, JSX, Firebase, Enzyme, JSON Web Tokens (JWT), Less, PostgreSQL, Redux, Redis, NoSQL, MySQL, Jira, Scrum, YouTube API, Responsive Web Apps, Agile Software Development, Bootstrap, SQL, Full-stack, APIs, Front-end, Back-end, Web Development, Amazon Web Services (AWS), Serverless, Twilio, Startups, Slack, Linux, Figma, AWS Step Functions, Amazon S3 (AWS S3), REST APIs, WebSockets, Material UI, Styled-components, NPM, Unit Testing, Software Engineering, HTML5, ECMAScript (ES6), User Interface (UI), UI Components

Full-stack Developer

2018 - 2018
  • Worked with US clients using the Ruby on Rails framework.
  • Developed new functionalities for fintech and healthcare portals.
  • Fixed issues and migrated the legacy Rails app to newer versions.
Technologies: Ruby, Ruby on Rails 4, JavaScript, jQuery, HTML, CSS, Redis, PostgreSQL, RSpec, Ruby on Rails 5, Slack, Linux, Heroku, REST APIs, Unit Testing, Software Engineering, HTML5, ECMAScript (ES6), User Interface (UI)

Reporting Tool for Delta Dental

Led the front-end development of interactive business analytics using React, TypeScript, and React Query. Brought Figma designs to life by creating UI components with Material UI, making sure they look great on all screen sizes and devices.

I implemented flexible integration, robust authentication, powerful reporting, data privacy, and custom branding. I integrated Bold BI reports to enhance IBA's reporting capabilities. The application was hosted securely on AWS for scalability.

Also, I documented the project and laid the groundwork for future enhancements.

Calendar App for ITV

Added new features, fixed bugs, and maintained and refactored the Calendar App for a large TV-show company in the US using React, Node.js, JavaScript, Firebase, Jest, and CircleCI. This project included a undo and redo cache implemented with Redux and and HTML to PDF rendering tool.

Laser GG Sharing Service
Created a secure REST API to share 3D printing resources for a medium client in the US using Node.js, TypeScript, NestJS, GCP, and JWT. The service has been successfully used every day by thousands of users.
2010 - 2015

Bachelor's Degree in Computer Systems Engineering

Pontifical Catholic University Mother and Teacher - Santiago, Dominican Republic


Introduction to OpenAI API & ChatGPT API for Developers



NestJS Zero to Hero - Modern TypeScript Back-end Development



Node.js, React, REST APIs, React Redux, Twilio API, Redux-Saga, YouTube API, Google Calendar API, Marko.js, jQuery, React Query, React Testing Library


Slack, Git, GitHub, Bitbucket, Jira, Figma, AWS Step Functions, NPM, Amazon Simple Notification Service (Amazon SNS), Amazon CloudFront CDN, JSX, Webpack, CircleCI, RSpec


JavaScript, HTML, HTML5, ECMAScript (ES6), TypeScript, SQL, CSS, Less, Ruby, Python, GraphQL, CSS3


Unit Testing, Agile Software Development, Scrum, Design Patterns


MongoDB, PostgreSQL, NoSQL, MySQL, Amazon S3 (AWS S3), Redis, SQLite, SQL Injection Protection


NestJS, Redux, Bootstrap, Koa, Express.js, JSON Web Tokens (JWT), Material UI, Jest, Next.js, Ruby on Rails 4, Ruby on Rails 5


MacOS, Linux, Firebase, Heroku, Amazon Web Services (AWS), Twilio, Google Cloud Platform (GCP), AWS Lambda, AWS Elastic Beanstalk, Vercel, Azure


Software Engineering, Web Development, Full-stack, APIs, Front-end, Back-end, User Interface (UI), Material Design, TypeORM, Enzyme, Responsive Web Apps, Serverless, Startups, WebSockets, Styled-components, Storybook, UI Components, Amazon RDS, ESLint, Software Design, Computer Science, Algorithms, SQL Server 2015, Google Cloud Functions, Chakra UI, OpenAI GPT-3 API, OpenAI GPT-4 API, BI Reporting, OWASP, XSS Protection, Security

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