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Williams Aguilera
Verified Expert in Engineering
Technical Leadership Developer
Madrid, Spain
Toptal member since September 7, 2015
Bio
Williams is an experienced developer with 20+ years in software development, spanning desktop, web, front-end, back-end, and databases, and has served as an architect, tech lead, and CTO for startups. With expertise in Node.js, Python, AngularJS, and microservices architecture, he is an IoT enthusiast, clean code advocate, and problem solver. Williams is proficient in Docker, Kubernetes, Jenkins, and MongoDB and is passionate about creating scalable, tech-driven solutions for complex problems.
Portfolio
Bobsled
Terraform, Infrastructure as Code (IaC), Jest, Node.js, TypeScript...
Nova
Node.js, MySQL, Amazon Web Services (AWS), React, SQL, CSS3...
cloud.IQ
PubSubJS, Vue, Terraform, Helm, Kubernetes, Google Cloud Platform (GCP)...
Experience
- JavaScript - 9 years
- MySQL - 9 years
- React - 8 years
- Node.js - 5 years
- MongoDB - 3 years
- Technical Leadership - 3 years
- RabbitMQ - 3 years
- Amazon Web Services (AWS) - 3 years
Work Experience
Principal Engineer
2024 - PRESENT
Bobsled
- Designed and implemented a scalable cross-cloud data sharing feature that allowed to transfer data from sftp sources to warehouses.
- Worked on improving the development process of a high-performing engineering team, improving code deployment efficiency, product communication, and production pipelines.
- Collaborated with product managers to align technical initiatives with business goals, driving the successful integration of many new features to the platform.
Technologies: Terraform, Infrastructure as Code (IaC), Jest, Node.js, TypeScript, Amazon Web Services (AWS), Amazon Simple Queue Service (SQS)
Chief Technology Officer
2020 - 2024
Nova
- Migrated and redesigned the whole platform from PHP and Clojure into Node.js and React.
- Led the engineering team and set up the Agile methodology and the remote-first, async-first way of working.
- Helped the organization create a scalable, robust, testable platform capable of handling the expected user growth.
- Set up the whole infrastructure in AWS using Terraform for IaC and managed different services such as SQS, RDS, and EBS.
Technologies: Node.js, MySQL, Amazon Web Services (AWS), React, SQL, CSS3, Agile Software Development, Scrum, HTML5, Software Architecture, Full-stack Development, React Native, TypeScript
Technical Lead
2019 - 2020
cloud.IQ
- Led the engineering team for CloudIQ in Madrid, growing and scaling the platform.
- Helped the company move forward from a startup to a more consolidated engineering division that could hold up to the industry standards.
- Collaborated with the engineers, developers, DevOps, and QA specialists, helping them set up a robust, resilient, scalable infrastructure that would perform adequately according to the company's requirements.
- Set up a fully automated infrastructure in Google Cloud Platform with Node.js. It can handle around 150 requests per second with peaks of about 300 requests per second, with the capability of scaling up and down depending on the needs.
- Coordinated and helped other engineering teams across the company.
- Built testing and quality culture cross-company, defining standards, processes, and methodologies to remotely coordinate the work.
- Developed a dashboard with Vue to manage all admin endpoints for the platform.
- Cleaned the platform code to allow it to scale without problems.
Technologies: PubSubJS, Vue, Terraform, Helm, Kubernetes, Google Cloud Platform (GCP), Google Cloud Spanner, Node.js, SQL, Agile Software Development, Scrum, Software Architecture, TypeScript, Python
Technical Lead
2018 - 2019
Denizen Financial
- Built clean and scalable APIs to support the load of a global fintech neo bank.
- Led the engineering team in developing and implementing the technologies needed to create the core bank's platform.
- Developed REST APIs with Node.js to create the core banking platform.
- Handled integrations in Node.js to communicate with external banking providers.
- Set up a resilient infrastructure using messaging queues with RabbitMQ.
- Built a whole test automation framework with Python to run automated tests in our CI.
- Helped set up a scalable, highly-available infrastructure with Kubernetes and Terraform.
- Led the implementation of Agile methodologies to manage the tech team's workload with Scrum.
- Spearheaded the creation of a back-office tool made with React and Redux.
- Developed a cross-platform, secure banking app using Ionic.
Technologies: Amazon Web Services (AWS), React, APIs, Kubernetes, Docker, RabbitMQ, MongoDB, Ionic, Angular, JavaScript, Node.js, CSS3, Agile Software Development, Scrum, HTML5, Software Architecture, Full-stack Development, TypeScript, OpenAI API, Python
Software Architect
2016 - 2018
Beeva
- Developed prototypes for the new digital business department.
- Created hybrid applications with Ionic and Node.js.
- Led an engineering team in developing a full-fledged banking infrastructure based on dockerized microservices, which communicate through a RabbitMQ messaging queue, orchestrate using Kubernetes, and expose externally using Kong API manager.
- Spearheaded the integration and aggregation of external banking providers through queues and REST APIs.
- Built a robust software communication infrastructure that supports banking transactions and is resilient.
- Researched and made POCs exploring the possibilities of IoT, blockchain, and new technologies in the fintech area.
Technologies: Amazon Web Services (AWS), Blockchain, APIs, Kubernetes, RabbitMQ, MongoDB, Ionic, Angular, JavaScript, Node.js, CSS3, Scrum, HTML5, Software Architecture, TypeScript
External Consultant
2016 - 2016
Gennion Solutions
- Supported the development of a custom web dashboard to show the data gathered from a sensor network for marketing purposes in a graphical way.
- Advised the engineering team on how to build the front end in a scalable way using Angular.
- Helped with the design of the back-end API to make it RESTful and follow standards.
- Worked with a custom tool building visualization widgets from the data gathered.
- Helped with the creation of data models to capture insights about the product.
Technologies: Angular, Node.js, JavaScript, CSS3, Full-stack Development
Research Engineer
2015 - 2016
Center of Biomedical Technologies UPM
- Contributed to a European Union project aimed at researching technological solutions that might improve the lives of elderly patients.
- Worked with IoT in the early detection of the frailty of elderly patients.
- Developed a hybrid app using Ionic and Angular to gather data from sensors and show the results in real time.
- Used Arduino and sensors for building a prototype to perform Gait analysis.
- Articulated with one of the top hospitals in Spain to validate the solution directly with their elderly patients.
- Wrote a paper to expose the results of the experiment and prototype.
Technologies: Internet of Things (IoT), Sensors & Actuators, Angular, Ionic, Raspberry Pi, Arduino
Full-stack Developer
2015 - 2016
BBVA
- Developed front-end platforms to visualize data gathered with IoT.
- Created hybrid mobile apps with Ionic and Angular for innovative fintech projects in the area of blockchain and smart contracts.
- Built dashboards using D3 to show IoT device information.
- Created POC leveraging blockchain (Ethereum) to book internal rooms.
Technologies: Blockchain, Internet of Things (IoT), D3.js, Node.js, Angular, JavaScript, Full-stack Development
Senior Web Developer
2015 - 2015
Any Help International
- Developed a web-based application to keep track of service behaviors through a graphical interface for a client in the banking industry.
- Consulted and advised on web technologies and recommended frameworks and methodologies to work with.
- Trained on web technologies such as jQuery, Bootstrap, and CSS3 to other members of the team.
- Modified and improved the existing development in order to ensure responsiveness.
- Trained and consulted with the client about the app development process.
Technologies: Java, CSS, HTML, jQuery, CSS3
Web Developer
2015 - 2015
It's for You
- Developed a CMS for the handling of the company's website.
- Built a responsive company website with multi-language support.
- Created an administrative area to manage the creation and configuration of QR Codes.
- Programmed a user zone, where the QR card holders could edit its content and manage the layout.
- Wrote a visualization responsive area where final users could see multimedia content that had been uploaded and download it themselves.
Technologies: MySQL, PHP, AngularJS, CSS3
Web Developer
2014 - 2015
Seeketing SL
- Developed a graphical web interface, with jQuery and kinetic, to draw and monitor crowd movements in a map through heat maps.
- Upgraded an existing platform from Bootstrap 2 to Bootstrap 3.
- Built an automatized web platform to schedule, monitor, and measure scripts that ran in the crontab of a Linux server.
- Programmed a web application to monitor the state of external nodes and check for data integrity.
- Experimented with the migration and handling of big data through MongoDB.
- Created a web application that normalized and filled data gaps in a time frame through the application of models.
- Developed a Scrum-like working methodology to apply within the work team.
Technologies: Bootstrap, CSS, HTML, AngularJS, MongoDB, MySQL, jQuery, PHP
Senior Web and Mobile Developer
2011 - 2014
Insysoft
- Developed a web front-end for an ERP system using XML communication.
- Built a web help assistant for CRM, with CMS, using PHP and JavaScript, with HTML and CSS.
- Developed an Android app using Xamarin Studio and C# to support ERP features, including XML communication, Bluetooth printing, push notifications, real-time invoicing, and stock modification, among other features.
- Improved an existing application developed in C# for Windows Mobile to ensure data integrity and security.
- Trained team in different technologies such as C# and web frameworks, among others.
- Wrote and organized documentation for both new and existing projects with standard ISO templates.
Technologies: Visual FoxPro, XML, SQLite, MySQL, CSS, HTML, JavaScript, PHP, C#, Android
Web Developer
2013 - 2013
Museu da gente sergipana
- Developed an interactive web game section for children that mimics some museum installations.
- Created a web application that allowed users to upload their pictures, dress themselves in a North-East Brazilian sort of way, and download those images for themselves.
- Wrote a virtual tour for the museum, using QR codes and single web pages of information.
- Built a QR code manager that allowed for editing and customization of the looks of the QR codes and the URLs where they pointed.
- Translated all the museum plaques and information from Portuguese to both Spanish and English.
Technologies: QR Codes, CSS, HTML, JavaScript, PHP, jQuery
Project History
Content Controller
A simple AngularJS controller that handles the behavior of an image with a text creation website. It includes a variable watch, a directive to bind textarea content to an ng-model, a function to save container content as a PNG, and a simple plain JavaScript function to check for the occurrences of a substring in a string. This controller is part of a more extensive website made to create, manage, and use QR codes.
It's for You Website
Developed a website to advertise, display, and manage QR cards in multiple languages, including user area, cards, and content management. The site manager can create, edit, and delete batches of QR codes in the management area for multiple clients. The site was developed using Bootstrap 3, HTML, CSS, jQuery, AngularJS, and PHP for the back-end and MySQL for the database.
Orion Media Website
Developed a website for advertising purposes for the company Orion Media, using WordPress for content management and Bootstrap 3 to ensure the responsiveness of the site on multiple devices (not the current website).
Discovery's Group Website
Developed and managed a website for advertising purposes, including a media galleries module, using PHP, MySQL, jQuery, and Bootstrap. I also created a content handler for the self-management of the page by the owners.
Financial Retirement Calculator
Developed a retirement calculator based on parameters given by the client and embedded it on an existing WordPress website. It is responsive and mobile-adapted, and it has the option to send the results, with the embedded graph, through email.
It is created using jQuery, HTML, CSS, and a graphic framework.
It is created using jQuery, HTML, CSS, and a graphic framework.
Hidric Footprint Calculator
Developed an interactive, kid-friendly web app to calculate the amount of water used by a person daily, according to some given parameters. I created the app using jQuery, HTML, CSS, and PHP.
The app was animated, and its content and configuration were handled externally so that it could be edited easily in case of changes.
The app was animated, and its content and configuration were handled externally so that it could be edited easily in case of changes.
Game Area for the Museum
Developed the interactive game section for kids on the museum website, using web technologies such as JavaScript, HTML, CSS, and PHP, among others. This section was meant to be a digital representation of the museum's interactive installations for kids.
Tweaks and Integrations for a WordPress Site (via Toptal)
I developed a WordPress site with a PayPal gateway for payments, AngularJS integration, social media auth, and notifications in this project.
The project was already set up, so the primary task involved integrating new modules to expand the site’s functionality.
The project was already set up, so the primary task involved integrating new modules to expand the site’s functionality.
Custom Secure Forms Framework
I worked on creating a custom JavaScript framework that generated forms that were ready to be included in a secure app that was HIPAA-compliant and ready for the medical industry.
This engagement was initially just about building the forms, but by creating this framework, we delivered forms quickly, improving times by around 80%.
This engagement was initially just about building the forms, but by creating this framework, we delivered forms quickly, improving times by around 80%.
Candidate Screening Platform and Back Office
Built a modular screening platform using React and Next.js with a Node.js back end. This platform not only allows to screen applicants to Nova but also can be configured in different flavors to work for any other process for clients.
Its modules can be easily configured, moved, or even removed, for a custom experience for each user.
This platform also has a back office that allows screeners to quickly review, approve, or reject candidates using efficient UX and AI tools.
Its modules can be easily configured, moved, or even removed, for a custom experience for each user.
This platform also has a back office that allows screeners to quickly review, approve, or reject candidates using efficient UX and AI tools.
Nova Talent Mobile App
https://www.novatalent.comDevelopment of a fully functional mobile app using React Native, leveraging on the current web app they had. Since the company had a very small team, what we did was adapt both apps so that they could work seamlessly, having to maintain a single codebase, while also providing a native-like experience for users.
To-do App in Svelte for Electron
https://github.com/webnator/todo-appA sample to-do app built to explore the capabilities of using Svelte to pack an app for native deployment through Electron.
The app connects with a Node.js back end that uses WebSockets for real-time communication with the front end.
TailwindCSS was used to style the platform, and an innovative layered architecture through containers was applied for the front end to allow for scalability, testability, and modularization.
The app connects with a Node.js back end that uses WebSockets for real-time communication with the front end.
TailwindCSS was used to style the platform, and an innovative layered architecture through containers was applied for the front end to allow for scalability, testability, and modularization.
Education
2014 - 2016
Master's Degree in Software Engineering
Universidad Politecnica de Madrid - Madrid, Spain
2005 - 2010
Information Engineer's Degree in Computer Engineering
Universidad Tecnologica del Centro - Valencia, Venezuela
Certifications
JANUARY 2017 - JANUARY 2019
Certified ScrumMaster
Scrum Alliance
OCTOBER 2016 - PRESENT
C100DEV: MongoDB Certified Developer Associate Exam
MongoDB University
SEPTEMBER 2016 - PRESENT
Big Data on AWS
qwikLABS, Inc.
AUGUST 2016 - PRESENT
Serverless Design with AWS Lambda
quikLABS, Inc.
JULY 2016 - PRESENT
C100DBA: MongoDB Certified DBA Associate Exam
Mongo University
MAY 2016 - PRESENT
M202: MongoDB Advanced Deployment and Operations
Mongo University
DECEMBER 2015 - PRESENT
M102: MongoDB for DBAs
Mongo University
DECEMBER 2015 - PRESENT
M101JS: MongoDB for Node.js Developers
Mongo University
Skills
Libraries/APIs
React, Node.js, Vue, OpenAI API, jQuery, D3.js, PubSubJS, Google API, Mobile HTML5
Tools
Sublime Text 2, Git, RabbitMQ, Subversion (SVN), Google Kubernetes Engine (GKE), Helm, Terraform, Amazon Simple Queue Service (SQS)
Languages
JavaScript, SQL, CSS3, HTML, HTML5, TypeScript, PHP, CSS, Java, C#, XML, Visual FoxPro, Python, PHP 7
Frameworks
Ionic, Hapi.js, Bootstrap 3, AngularJS, Laravel 5, React Native, Bootstrap, Angular, JSON Web Tokens (JWT), Unity3D, ZURB Foundation, OAuth 2, Jest, Next.js, Svelte, Electron, Tailwind CSS
Paradigms
Agile Software Development, Scrum, Responsive Web Design (RWD)
Storage
MongoDB, SQLite, MySQL, Google Cloud Spanner, Microsoft SQL Server, PostgreSQL
Platforms
MacOS, Linux, Android, Blockchain, Arduino, Raspberry Pi, Kubernetes, Docker, Amazon Web Services (AWS), Google Cloud Platform (GCP), Visual Studio Code (VS Code), WordPress, AWS Lambda
Other
Apps, Technical Leadership, Software Architecture, Full-stack Development, QR Codes, Version Control, Internet of Things (IoT), Sensors & Actuators, Software Engineering, Computer Engineering, APIs, SaaS, PayPal, Serverless, Infrastructure as Code (IaC), User Interface (UI), Web UX, SvelteKit, WebSockets, Architecture
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