Paulo Bing, Developer in Barcelona, Spain
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Paulo Bing

Verified Expert  in Engineering

Back-end Developer

Barcelona, Spain
Toptal Member Since
July 7, 2022

Paulo is a back-end engineer and full-stack developer with 15+ years of experience in the IT industry. He specializes in Spring Boot, Java, and JavaScript technologies. Paulo enjoys learning new tools and languages and using the common practices and methodologies in the market to deliver solutions that meet clients' requirements.


Spring Boot, Java, Docker, Spring Data, MySQL, PHP, Amazon Web Services (AWS)
Happy Cow
PHP, JavaScript, Git, PhalconPHP, Web Services, HTML5, Docker, Memcached...
Java 11, Spring Boot, Spring 5, Oracle, JavaScript 6, Node.js, GraphQL, MySQL...




Preferred Environment

MacOS, IntelliJ IDEA, Spring Boot, Jira, Slack

The most amazing...

...thing I've done is the migration of PHP microservices into a Spring Boot MS, being able to fully understand the features of the European DIY eCommerce.

Work Experience

Senior Back-end Engineer

2021 - 2022
  • Migrated the PHP microservices to Spring Boot microservices to track and return products for this DIY, home improvement, and gardening eCommerce.
  • Participated in several meetings and Scrum ceremonies with product owners and developers of the team that initially developed the PHP legacy microservices to fully understand the flow before migrating and to document it properly.
  • Reviewed code developed by other team members and suggested changes when the code was not suitable for merging with the main branch in Git.
  • Created new features and fixed bugs using Jira as a reporting tool.
Technologies: Spring Boot, Java, Docker, Spring Data, MySQL, PHP, Amazon Web Services (AWS)

Freelance PHP Full-stack Engineer

2021 - 2021
Happy Cow
  • Developed the world's most used app for searching vegan and vegetarian restaurants, shops, and other venues.
  • Created the documentation for the onboarding of new developers.
  • Implemented many features to the web application and the company's back office.
  • Participated in implementing the Veganuary hashtag campaign, which had certain special features and endorsed a plant-based diet during January.
  • Fixed the Docker configuration for the project in the local environment and documented the process, reducing dependencies for new developers when they started working.
Technologies: PHP, JavaScript, Git, PhalconPHP, Web Services, HTML5, Docker, Memcached, Redis Queue

Senior Back-end Engineer

2019 - 2021
  • Developed a customer service platform used by high-profile companies in France, Belgium, and the USA.
  • Implemented integrations with several communication channels for inbound and outbound messages from SMS, WhatsApp, Facebook Messenger, email, widgets, and the company's API.
  • Used cutting-edge technology in every single microservices or module of the project to make the application robust, fast, and secure. Technologies included Datadog, Elasticsearch, DynamoDB, and many solutions provided by AWS.
  • Participated in meetings with key users, developers, managers, and all relevant Scrum ceremonies.
Technologies: Java 11, Spring Boot, Spring 5, Oracle, JavaScript 6, Node.js, GraphQL, MySQL, Docker, Amazon Web Services (AWS), Gradle, JUnit, Behavior-driven Development (BDD), Integration Testing, CircleCI, Git, Scrum, Jira, Amazon DynamoDB, Elasticsearch

Senior Full-stack Developer

2017 - 2019
  • Developed a framework with JSF and PrimeFaces and various features for a healthcare company and fixed several bugs.
  • Started a new framework using Spring Boot to be used by the other teams in the company who developed customized software for each healthcare client in Belgium, Chile, and France.
  • Acted as a consultant for JSF, PrimeFaces, and jQuery in the company.
  • Built many solutions such as Taglibs, JavaScript functions or modules, and some CSS to help teams achieve possibilities not supported by PrimeFaces.
Technologies: Java, Spring Boot, Spring 4, Oracle, JSF, PrimeFaces, jQuery, CSS, HTML5, Apache Tomcat, Docker, Kubernetes, Apache Maven, Jenkins, Git, Git Flow, Scrum, Jira, Apache, JavaScript

Front-end Developer

2017 - 2017
Alto Analytics
  • Developed a social network data and news analyzer application used by many companies that wanted to gather posts, hashtags, and information related to a specific area of interest to support decision-making.
  • Implemented several new front-end features for the company's main product.
  • Contributed to an extra project using Canvas that served as a landing page for a new product.
Technologies: Java, Apache Struts 2, HTML5, CSS, JavaScript, jQuery, Apache Tomcat, Apache, Ant Design, Apache Maven, Web Services, CVS, Oracle, Jenkins, Jira

Senior Back-end Engineer

2016 - 2017
eDreams ODIGEO
  • Developed internal systems for the revenue department of eDreams using mainly Java on the back end.
  • Handled support tickets by providing a solution or assigning them to the right team after checking documentation and code and contacting other teams.
  • Participated in a few business meetings with other team members or other teams to discuss possible new features.
Technologies: Java, Behavior-driven Development (BDD), Java 6, Java 8, Web Services, JBoss, Ant Design, Apache Maven, Mercurial, Oracle, Jenkins, Jira, Kanban

Senior Full-stack Developer

2014 - 2016
Travel Compositor
  • Developed an online travel agency SaaS app that integrated with 20+ providers, primarily for transportation, tickets, hotels, and payment methods.
  • Implemented the integration with four providers from scratch, participated in technical meetings with providers, wrote documentation, and conducted testing and deployment to production.
  • Scaled the business from six to 20 employees in only two years, contributing to the company receiving many awards, investments, and new clients.
Technologies: Java, JSF, PrimeFaces, Enterprise Java Beans (EJB), JUnit, Web Services, Apache TomEE, Apache Maven, MariaDB, Jenkins, jQuery, CSS, JavaScript, Bootstrap, Scrum, Jira, Amadeus

Shell Scripts to Simulate Scenarios or for Testing

Almost every project encounters time wasted on a certain step of the application usage or any day-to-day activity that can be improved by automating it.

In such situations, I create something that could simulate specific scenarios, such as shell scripts, aliases, Java batch processes, stored procedures, or customized Cucumber feature files for development purposes. The team usually likes the ideas, and people start sharing theirs in a way that sometimes what was one person's problem was also another team member's problem who created a solution for it.

The result is increased team productivity, enabling team members to focus on what matters instead of repetitive and lengthy operations prone to errors.

Feature Toggle Microservices

A Java Spring Boot-based microservices app inside a Docker Composer that used a single table with MySQL with each feature toggle key, description, and status (enabled or disabled).

I developed its first version from scratch and created endpoints to get all the feature flags and one single feature flag—cached, for the front end, or for the back end. It also enabled creating, changing, or deleting the feature flag to refresh all caches in case of an update by a database. The second version of this app also made it possible to have other parameters to determine the status of each feature flag, such as user, agency, company, and general, where the top priority of each feature was the user.

The microservices allowed the team or admins to easily enable or disable the feature in case the time for release was due, or the campaign was over. Once it was entirely on or off after a particular time, we deleted the feature toggle key and its mentions in the code to keep it clean.

Arabic Right-to-Left HTML and CSS Adjustments
A SaaS app built with JSF, PrimeFaces, Bootstrap, and CSS for travel agencies.

As the full-stack developer, I adjusted our dynamic code to Arabic and potentially other right-to-left (RTL) languages as it required several changes in CSS and HTML. We had to avoid unexpected behavior, such as strange behavior with the pictures slideshows, which we adjusted to slide LTR, or some CSS property causing something to lose its margin, disappear, or overlap with something. We also had to consider that PrimeFaces generated CSS that sometimes was tricky to handle because changing on RTL could impact the LTR languages.

We successfully delivered the expected solution with a lot of research, reading Bootstrap and PrimeFaces CSS documentation, paying attention, and conducting Selenium tests.

Reverse Engineering Microservices Migration to Java

A PHP-based microservices for product returns of an eCommerce website.

I was the back-end developer within a team responsible for migrating it to Spring Boot microservices. We gathered all the requirements from PHP microservices and designed a solution and Java architecture according to the company's guidelines. We also implemented the MS that was still used by other teams, did reverse engineering, tested the legacy MS, created as many tests as we could, and documented everything.

We finished the migration with a team of two developers in only three months, enabling us to focus on new features.
2006 - 2011

Bachelor's Degree in Information Systems

Mackenzie Presbyterian University - São Paulo, Brazil


Sun Certified Java Programmer

Sun Microsystems


REST APIs, Node.js, jQuery, Redis Queue


Git, Jira, Cucumber, Slack, Gradle, CircleCI, Apache Tomcat, Apache Maven, Jenkins, Apache, CVS, Mercurial, Docker Compose, Postman


Spring Boot, Spring, JUnit, JPA, Hibernate, JSF, Spring Batch, Spring 5, Spring 4, PrimeFaces, Apache Struts 2, Ant Design, Bootstrap, PhalconPHP, Selenium


REST, Scrum, Behavior-driven Development (BDD), Kanban, Microservices


Java, JavaScript, Java Persistence Query Language (JPQL), PHP, COBOL, C, C++, Java 11, JavaScript 6, GraphQL, CSS, HTML5, Java 6, Java 8


Spring Data, MySQL, SQL Stored Procedures, Amazon DynamoDB, Elasticsearch, MariaDB, Memcached


Oracle, Docker, Amazon Web Services (AWS), Kubernetes, JBoss


Data Structures, Shell Scripting, Integration Testing, Git Flow, Web Services, Enterprise Java Beans (EJB), Apache TomEE, Amadeus, Reverse Engineering

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