Juan is available for hire
Hire JuanJuan Mendoza
Verified Expert in Engineering
Software Engineering Developer
Bilbao, Spain
Toptal member since November 9, 2022
Bio
Juan is a self-motivated software engineer and a certified AWS architect. With more than 14 years of experience in software engineering, leading and participating in successful cross-functional teams, Juan loves to work in close collaboration with product and design teams to achieve company goals and OKRs.
Portfolio
Gartner
React, Next.js, NPM, TypeScript, CircleCI, CI/CD Pipelines, GitHub, Bitbucket...
Delivery Hero
Ruby on Rails (RoR), Spring Boot, Kotlin, React, Node.js, Microservices...
Delivery Hero
Management, Software Engineering, TypeScript, REST APIs, Docker, Docker Compose...
Experience
Availability
Full-time
Preferred Environment
Spring Boot, Java, Kotlin, Node.js, React, Amazon Web Services (AWS), Kubernetes, Terraform, PostgreSQL, Next.js, Data Modeling, Supabase, APIs
The most amazing...
...projects I've delivered helped companies reach their goals by splitting monolith systems into microservices or creating scalable solutions.
Work Experience
Lead Software Developer
2023 - PRESENT
Gartner
- Migrated the existing social network, using Next.js 14, React, and TypeScript to boost performance and organic traffic, reducing the page loading time from around 20s to 0.9s using server-side rendering and infinite scrolling on the client side.
- Implemented a new set of end-to-end (E2E) test suites to improve the quality of the project using Playwright, TypeScript, and Page Object Models, covering most of the main user flows on the site.
- Created automation to set up local environments for new developers, reducing the onboarding time from around four days to less than an hour, using a combination of homebrew and shell tools.
- Improved existing and new pipelines on our CI/CD to ensure quality at all stages of the development cycle by running all project tests in parallel and guaranteeing that all projects are properly built without errors on CircleCI.
- Shared knowledge with all front-end engineers on the use of Playwright and TypeScript as an E2E testing tool in several workshops.
- Increased code quality across projects by leveraging multiple code quality tools, such as Husky, Prettier, ESLint, lint-staged, and TypeScript, making all of these technologies work together without disrupting the current developer experience.
- Interviewed several candidates as one of the final steps of the hiring process for senior front-end and full-stack developers for the teams in the organization.
- Optimized CI/CD pipelines, improving time to market from two hours to five minutes, using GitHub Actions and AWS CDK.
- Created a scalable UI component library based on the company's design system using React, TypeScript, and CSS.
Technologies: React, Next.js, NPM, TypeScript, CircleCI, CI/CD Pipelines, GitHub, Bitbucket, CSS, HTML, JavaScript, Go, Shell, Playwright, E2E Testing, Jest, Amazon Web Services (AWS), Amazon S3 (AWS S3), Amazon Elastic Container Registry (ECR), Amazon Elastic Container Service (ECS), Amazon CloudFront CDN, MongoDB, DocumentDB, Amazon EKS, Technical Leadership, Automation, Containerization, Containers, Responsive Web Design (RWD), HTML5, Leadership, Full-stack Development, SQL, AWS Lambda, AWS Fargate, CSS3, Storybook, OpenTelemetry, Solution Architecture, Microservices Architecture, Front-end Architecture, API Integration, Web Development, User Experience (UX), User Interface (UI), Data Modeling, APIs, Chart.js, Dashboards, Analytics, Charts, Contentful, Headless CMS, MySQL, Front-end Development, Event-driven Architecture, Single-page Applications (SPA), Amazon API Gateway
Staff Software Engineer
2021 - 2023
Delivery Hero
- Developed a product from scratch that generates landing pages that are deployed in all continents and in more than 60 countries, using Gatsby, TypeScript, Cloudflare, Amazon S3, and more AWS services.
- Improved CronJobs on a legacy service using Ruby, Rails, PostgreSQL, and Kubernetes to fine-tune database interactions and redesign some of the CronJobs to add more granularity to the execution, reducing database instances and costs by 50%.
- Migrated two services (1,000 rpm) from a regional base to a country base without downtime. Implemented missing functionality, created new instances, migrated data, switched the API gateway, and imported delta data files.
- Implemented AWS Lambda functions to replace the short URLs external providers widely used in the Delivery Hero ecosystem, saving over €1.000 per month. Used AWS Lambda, Node.js, Terraform, and Kong API Gateway.
- Created a new microservice to generate static landing pages, deprecating external providers and reducing over €5.000 in monthly costs, and improving the conversion rate by 60%. Used Spring Boot, Kotlin, React, Gatsby Drone CI, Amazon S3, and Cloudflare.
- Contributed to our load-test suite with several test scenarios where we tried to put our services under a lot of stress by simulating multiple requests growing exponentially, reaching our goal of handling 10x peak load, using Scala and Gatling.
- Redesigned all landing pages for all the different brands of Delivery Hero across the globe in 60 countries. We achieved this by offering full customization in terms of design, images, colors, fields, language, etc.
Technologies: Ruby on Rails (RoR), Spring Boot, Kotlin, React, Node.js, Microservices, Kubernetes, Helm, Terraform, PostgreSQL, Gatsby, Drone CI, Amazon S3 (AWS S3), CSS, Software Engineering, Spinnaker, Redux-Saga, REST, Kong, TypeScript, REST APIs, Docker, Docker Compose, Front-end, Redux, Amazon Web Services (AWS), AWS Cloud Architecture, Architecture, Enterprise Application Architecture, Full-stack, Storybook, Bootstrap, JavaScript Testing, Figma, Webpack, Ruby, Rust, Shell, JavaScript, Scala, Gatling, Load Testing, Technical Leadership, Automation, HTML5, Containers, Containerization, Responsive Web Design (RWD), NPM, Leadership, Full-stack Development, SQL, AWS Lambda, HTML, CSS3, Next.js, Solution Architecture, Microservices Architecture, Front-end Architecture, API Integration, Web Development, User Experience (UX), User Interface (UI), Data Modeling, APIs, Dashboards, Analytics, Contentful, Headless CMS, Event-driven Architecture, Front-end Development, Single-page Applications (SPA), Material UI, Amazon API Gateway
Engineering Manager
2020 - 2021
Delivery Hero
- Facilitated a work environment where my teams could share ideas and perform their best by promoting communication, removing roadblocks, listening to feedback on issues, and more.
- Conducted weekly one-on-one meetings and guided and mentored my team to grow their soft and technical skills, which resulted in six promotions in the individual contributor career path and one in the managerial career path.
- Defined hiring funnels for different positions in the logistics workforce. Achieving our ambitious hiring goals for six quarters in a row.
Technologies: Management, Software Engineering, TypeScript, REST APIs, Docker, Docker Compose, Front-end, Redux, Amazon Web Services (AWS), AWS Cloud Architecture, Architecture, Enterprise Application Architecture, Full-stack, Storybook, Bootstrap, JavaScript Testing, Figma, Cypress, Webpack, Technical Leadership, Responsive Web Design (RWD), Containers, Containerization, HTML5, NPM, JavaScript, Leadership, Full-stack Development, SQL, Ruby, AWS Lambda, HTML, CSS3, React, Solution Architecture, Microservices Architecture, Front-end Architecture, API Integration, Web Development, User Experience (UX), User Interface (UI), Data Modeling, APIs, Dashboards, Analytics, Contentful, Headless CMS, Front-end Development, Event-driven Architecture, Single-page Applications (SPA), Material UI, Amazon API Gateway
Engineering Lead
2017 - 2020
Care.com
- Split a monolithic application enhancing the first component of the recruitment process with an improvement of 50% in the loading time and 10% in the conversion rate, using React, Jest, and Puppeteer.
- Created a component library used across different teams, reducing the development time and achieving a better look and feel on all parts of the application. Here we used React, Emotion, and Storybook.
- Defined the scope of the project and implemented a new redesign, making sure that the whole team met our commitments on time, achieving close to 100% on-time delivery of all features assigned to the team.
- Shared knowledge by giving different workshops on front-end technologies such as React, Redux, styled-components, and Puppeteer, and on back-end technologies such as Kotlin, CircleCi, and Docker Compose.
- Conducted one-on-one weekly meetings and evaluated individual contributions.
- Redesigned the onboarding funnel completely, also called new user registration, where we used a mobile-first approach and created a set of reusable components that later would improve the development speed of other teams.
Technologies: Spring Boot, Java, Groovy, Grails, React, Styled-components, Management, Software Engineering, Engineering Management, TypeScript, REST APIs, Docker, Front-end, Redux, Amazon Web Services (AWS), AWS Cloud Architecture, Architecture, Enterprise Application Architecture, Full-stack, Storybook, Bootstrap, JavaScript Testing, Technical Leadership, Responsive Web Design (RWD), Containers, Containerization, HTML5, NPM, JavaScript, Leadership, Full-stack Development, SQL, HTML, CSS3, Solution Architecture, Microservices Architecture, Front-end Architecture, API Integration, Web Development, User Experience (UX), User Interface (UI), Data Modeling, APIs, Dashboards, Analytics, Contentful, Headless CMS, Front-end Development, Event-driven Architecture, Single-page Applications (SPA), Material UI
Senior Software Engineer
2015 - 2017
Oracle
- Implemented a recommendation engine based on user activity that helped engineers and sales teams find relevant information more efficiently.
- Developed an end-to-end testing framework with Selenium, Gradle, and Java 8 that considerably reduced the number of regression bugs.
- Built a cross-platform mobile application prototype with the same capabilities as a desktop site allowing engineers to manage all their tasks on their mobile devices. Using Ionic Framework, Angular, and Cordova.
- Created a React application to request and deliver feedback on the quality and relevance of the articles in the knowledge database widely used by support and sales engineers.
Technologies: Java, React, Apex, Oracle, Oracle Database, REST, Selenium, Ionic, Angular, PL/SQL, Spring MVC, Apache Maven, Gradle, REST APIs, Full-stack, Bootstrap, Cordova, AngularJS, Responsive Web Design (RWD), HTML5, NPM, JavaScript, Full-stack Development, SQL, HTML, CSS3, Solution Architecture, Front-end Architecture, API Integration, Web Development, User Experience (UX), User Interface (UI), Data Modeling, APIs, Dashboards, Front-end Development, Single-page Applications (SPA)
Senior Java Developer | Technical Lead
2012 - 2015
Internet Brands
- Implemented a feature to compare cars increasing daily visits from 1,000 to 10,000 users, using Vanilla JavaScript, HTML, CSS, and REST services.
- Created an email campaign and templating engine that sends emails to users based on their interests in vehicles or articles on the site, fully compliant with all email clients and sites.
- Collaborated and mentored a team from the USA, Uruguay, India, and Mexico in redesigning one of the top three sites of car sales in the USA.
Technologies: Java, Groovy, Apache Velocity, CSS, HTML, Oracle Database, JavaScript, jQuery, Spring MVC, REST APIs, Front-end, Full-stack, Bootstrap, Full-stack Development, Technical Leadership, MySQL, Responsive Web Design (RWD), Leadership, SQL, CSS3, Solution Architecture, API Integration, Web Development, User Interface (UI), Data Modeling, Front-end Development
Software Development Engineer
2010 - 2012
NIC Mexico
- Completed search, registration, and management of domain names with the .mx country code top-level domain (ccTLD).
- Created a parser to consume reports of payments from several bank institutions and register fulfilled transactions.
- Trained members on front-end technologies and JavaServer Faces (JSF) framework.
Technologies: Java, JSF, JavaScript, CSS, HTML, Oracle Database, Full-stack, Full-stack Development, SQL, Web Development, User Interface (UI), Front-end Development
Software Engineer Intern
2008 - 2010
The ITESM
- Developed a site that showed the grade of the students on a specific test.
- Implemented a registration application that tracked student assistance using a barcode.
- Created an application for the teachers to upload and format data of students' grades.
Technologies: Java, Jakarta Server Pages (JSP), jQuery, JavaScript, PHP, Visual Basic, AccessData, HTML, Web Development
Software Engineer Intern
2008 - 2009
Messicom
- Implemented a module to support multiple languages throughout the application, allowing users to translate into any language, when previously it was just English <> Spanish.
- Developed a new CMS module to create static content as landing pages.
- Simplified several modules of our custom CMS which helped with code maintainability and reduced bugs overall.
Technologies: PHP, CakePHP, JavaScript, jQuery, Linux, LAMP, Apache, MySQL, CSS, HTML, Web Development
Experience
Minimalist Personal Website
http://grekz.comI created an extremely minimalist website in less than a day using Gatsby, React, TypeScript, Cloudflare, Amazon S3, and pnpm. I had been postponing the creation of a portfolio site and one that could contain all the places where people can contact me. I finally managed to do a quick proof of concept, and this is the result.
Care.com: Landing Page and Registration of New Users
https://www.betreut.de/de-de/join-nowA React, Redux, and styled-components application that was split from a monolithic service. We improved the front-end stack, introducing React and Redux for user enrolment and to the whole European branch of the company, reducing load time by 50% and improving the completion rate by 10%. I was involved in this project's plan, design, implementation, and delivery phases.
Delivery Hero: Static Landing Page Creator
https://rider.foodpanda.com.tw/Dodo is a static landing page creator developed to replace the existing WordPress solution. On the back end, we used Kotlin, Spring Boot, and PostgreSQL, while on the front end, we used React and Gatsby. To generate and publish the pages, we used Drone CI. I participated on both sides of the application development process. The Rider Food Panda is an example of a page developed with Dodo.
Gartner.com: Migration of Private Social Network to Next.js 14
https://www.gartner.com/peer-communityA React Native for Web social network for top-level executives, created by one of the biggest IT firms in the world.
I was involved in the full-stack migration from React Native for Web to Next.js 14. We improved loading time from 20s to under 1s, increased traffic by +300%, and reduced the time to market for new features from two hours to under five minutes.
The platform runs on AWS, using AWS S3 to store assets, AWS ECS Fargate to run the container of the application, GitHub Actions as a CI/CD tool, React and TypeScript for the front end, Next.js as a framework, MongoDB as a database, Go as a back-end API, and AWS CDK as infra as code.
I was involved in the full-stack migration from React Native for Web to Next.js 14. We improved loading time from 20s to under 1s, increased traffic by +300%, and reduced the time to market for new features from two hours to under five minutes.
The platform runs on AWS, using AWS S3 to store assets, AWS ECS Fargate to run the container of the application, GitHub Actions as a CI/CD tool, React and TypeScript for the front end, Next.js as a framework, MongoDB as a database, Go as a back-end API, and AWS CDK as infra as code.
Delivery Hero: Hiring Platform
The hiring platform designed for Delivery Hero, a leading global food delivery company with operations in over 70 countries, has successfully streamlined and optimized recruitment processes for both the company and job seekers.
Leveraging technologies such as AWS, Cloudflare, React, Kotlin, Ruby on Rails, and PostgreSQL, this platform offered a user-friendly interface, powerful search capabilities, robust reporting and analytics tools, mobile responsiveness, enhanced candidate experience, scalability to accommodate diverse company needs, ongoing support and maintenance, and robust security measures.
As a result of this innovative solution, Delivery Hero has received millions of applicants across all continents, significantly reducing time-to-hire, increasing applicant quality, and improving overall recruitment efficiency, ultimately leading to a more productive and successful workforce.
Leveraging technologies such as AWS, Cloudflare, React, Kotlin, Ruby on Rails, and PostgreSQL, this platform offered a user-friendly interface, powerful search capabilities, robust reporting and analytics tools, mobile responsiveness, enhanced candidate experience, scalability to accommodate diverse company needs, ongoing support and maintenance, and robust security measures.
As a result of this innovative solution, Delivery Hero has received millions of applicants across all continents, significantly reducing time-to-hire, increasing applicant quality, and improving overall recruitment efficiency, ultimately leading to a more productive and successful workforce.
Oracle: Global Sales Engineering Platform
A global sales engineering management platform for Oracle, enabling efficient scheduling, meeting preparation, knowledge sharing, and product presentation support for sales teams across the organization.
This innovative solution was instrumental in fostering a more effective and collaborative working environment. The platform allowed us to customize our meetings based on the needs of each team, ensuring that every meeting was tailored to its specific audience and purpose. Moreover, it facilitated seamless knowledge sharing across different Oracle products, providing support for product presentations and promoting comprehensive understanding among sales teams.
This innovative solution was instrumental in fostering a more effective and collaborative working environment. The platform allowed us to customize our meetings based on the needs of each team, ensuring that every meeting was tailored to its specific audience and purpose. Moreover, it facilitated seamless knowledge sharing across different Oracle products, providing support for product presentations and promoting comprehensive understanding among sales teams.
Education
2005 - 2009
Bachelor's Degree in Computer Science
Instituto Tecnológico y de Estudios Superiores de Monterrey (ITESM) - Monterrey, Mexico
Certifications
MAY 2020 - PRESENT
Computer Vision Expert | Nanodegree Program
Udacity
APRIL 2020 - PRESENT
Reactive Architecture: Domain Driven Design - Level 2
Lightbend
APRIL 2020 - PRESENT
Course Artificial Intelligence Foundations: Neural Networks
LinkedIn Learning
APRIL 2020 - PRESENT
Reactive Architecture: Reactive Microservices - Level 2
Lightbend
APRIL 2020 - PRESENT
Reactive Architecture: Introduction to Reactive Systems - Level 2
Lightbend
APRIL 2020 - PRESENT
AI Programming with Python | Nanodegree Program
Udacity
JANUARY 2020 - JANUARY 2023
AWS Certified Solutions Architect Associate
AWS
Skills
Libraries/APIs
React, REST APIs, Node.js, jQuery, Chart.js, Redux-Saga, Playwright
Tools
JavaScript Testing, Kong, Docker Compose, Figma, Helm, Terraform, Flyway, Apache Maven, Gradle, Google Analytics, Webpack, NPM, CircleCI, GitHub, Bitbucket, Shell, Amazon Elastic Container Registry (ECR), Amazon Elastic Container Service (ECS), Amazon CloudFront CDN, AWS CLI, Gatling, Apache, Amazon EKS, AWS Fargate, AWS Cloud Development Kit (CDK), Amazon CloudFront
Languages
Java, CSS, HTML, JavaScript, SQL, HTML5, Kotlin, TypeScript, Ruby, CSS3, Python, Groovy, Apex, Go, Rust, Scala, PHP, Visual Basic
Frameworks
Bootstrap, Next.js, Spring Boot, Redux, Cypress, Material UI, Ruby on Rails (RoR), Grails, Selenium, Ionic, Angular, Spring MVC, Apache Velocity, JSF, Jest, CakePHP, AngularJS, Jakarta Server Pages (JSP), Swagger, Tailwind CSS
Paradigms
REST, Enterprise Application Architecture, Responsive Web Design (RWD), Microservices Architecture, Microservices, Management, Event-driven Architecture, E2E Testing, Load Testing, Automation
Platforms
Amazon Web Services (AWS), Contentful, Oracle, Docker, Kubernetes, Drone CI, Spinnaker, Oracle Database, Linux, LAMP, AccessData, AWS Lambda, Vercel
Storage
PostgreSQL, Amazon S3 (AWS S3), PL/SQL, MongoDB, MySQL, Oracle Database Tuning
Other
Software Engineering, Programming, Software Architecture, Front-end, AWS Certified Solution Architect, AWS Cloud Architecture, Architecture, Full-stack, Storybook, Technical Leadership, Full-stack Development, Leadership, APIs, Solution Architecture, Front-end Architecture, API Integration, Web Development, User Experience (UX), User Interface (UI), Data Modeling, Dashboards, Headless CMS, Front-end Development, Single-page Applications (SPA), Containers, Analytics, Charts, Amazon API Gateway, Gatsby, Computer Vision, AI Programming, Neural Networks, Artificial Intelligence (AI), API Gateways, Styled-components, Engineering Management, CI/CD Pipelines, PNPM, Cloudflare, Cordova, DocumentDB, Containerization, ESLint, GitHub Actions, Debugging, Cloud, Amazon RDS, OpenTelemetry, Supabase
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