Daniel is available for hire

Daniel Lungu

Verified Expert in Engineering

Software Developer

Bucharest, Romania

Toptal member since July 27, 2020

Expertise

Full-stack Java Spring Hibernate SQL MySQL JDBC Spring Boot REST API Front-end System Security JavaScript Git Linux Telerik

Bio

Daniel is a full-stack developer in Java technologies (Spring, Hibernate), front-end frameworks and libraries (React and Angular), and CI/CD pipelines. With over seven years of experience in developing applications for big companies such as IBM, BNP Paribas, Orange Telecom, UniCredit Bank, and startups, he has accumulated the right expertise to build, maintain, and manage a software product from the planning phase to its deployment, with the highest degree of professionalism and quality.

Portfolio

Freelancer

Redux, Stripe API, SQL, Full-stack, Java 8, Spring, Amazon Web Services (AWS)...

Orange Services

SQL, Full-stack, DevOps, Spring Boot, Java 8, Angular Material, Git, Jenkins...

IBM

SQL, Full-stack, Java, PL/SQL, Oracle Database, JavaScript, CSS, JDBC...

Experience

SQL - 7 years
Java - 7 years
Spring - 7 years
Hibernate - 7 years
Microservices Architecture - 5 years
Docker - 4 years
Angular - 4 years
React - 2 years

Availability

Part-time

Preferred Environment

Amazon Web Services (AWS), Agile, CI/CD Pipelines, Angular, React, JavaScript, Hibernate, Spring, Java, Git

The most amazing...

...platform I've developed helps sellers find the best supplier for a product and automates the client's ordering, shipping, and payment process.

Work Experience

Tech Lead | Senior Full-stack Software Developer

2020 - PRESENT

Freelancer

Worked as a tech lead on a team of five developers for a carbon analytics SaaS application. The application was developed with Spring Boot, Java 17, React, and Python and deployed to AWS in EC2 instances with Jenkins and Docker.
Developed an ergonomics SaaS application with Spring Boot, Java 17, TypeScript, Angular and deployed it to AWS with Terraform and Docker.
Built a stock market analytics platform that displays data in different charts for stock options for a specific stock symbol. The product was developed for the financial industry with Java 11, React, Spring Boot, PostgreSQL, and Highcharts.
Built a platform for sellers to find the best supplier for a product and automate the process of ordering, shipping, and paying for customers. The product was developed for the retail industry with Java 11, React, Spring Boot, PostgreSQL, and Stripe.
Developed a bot for the stock market to automate trading processes based on specific rules defined by the user in the UI. The product was created for the financial industry with Java 11, React, Spring Boot, and PostgreSQL and deployed in AWS.
Built a stock market system for a client from the financial industry. Improved the quality and the performance of the existing code and added unit and functional tests.
Oversaw an entire client's project—understood the client's needs, discussed the requirements, established the price and the deadline for new development, and delivered the solution.

Technologies: Redux, Stripe API, SQL, Full-stack, Java 8, Spring, Amazon Web Services (AWS), Agile, TypeScript, JavaScript, Stripe, Java 11, Apache Maven, Gradle, Apache Tomcat, Selenium, MySQL, PostgreSQL, Angular, React, Spring Boot, Java, Amazon EC2, Amazon RDS, Amazon S3 (AWS S3), Terraform, Linux, Cassandra, Apache Spark, Hadoop, Scala, Mockito, Microservices Architecture, MacOS, IntelliJ IDEA, Slack, Stock Market, Trading Systems, APIs, REST APIs, Web Services, Continuous Delivery (CD), Continuous Integration (CI), OAuth, OAuth 2, Node.js, Containers, Amazon EKS, Stock Trading, Banking & Finance, SCSS, Less, Front-end

Senior Full-stack Software Developer

2018 - 2020

Orange Services

Developed and maintained a device management system that manages and monitors over 10 million devices. The application is for the telecom industry and was developed with Java, Spring, MySQL, ElasticSearch, and Kafka and deployed in OpenShift.
Decoupled the user interface from the back end using REST services and migrated the application from an IaaS platform to a PaaS platform with CI/CD pipelines created with Docker, GitLab CI/CD, Kubernetes, and OpenShift.
Created a web application that simulates the TR69 protocol for testing different communication strategies with a device. The application is for the telecom industry, and it was developed with Java, Spring Boot, MariaDB, Angular, and TypeScript.
Managed a team of five members in developing a web application; established deadlines helped members in blocking points, discussed and established the requirements, monitored the development of the application, and followed Scrum methodology.
Held programming lessons for college students and participated in the interview process for a new candidate.

Technologies: SQL, Full-stack, DevOps, Spring Boot, Java 8, Angular Material, Git, Jenkins, GWT, OpenShift, Apache Maven, TypeScript, Scrum, Agile, Angular, Hibernate, Elasticsearch, Redis, Apache Kafka, MySQL, SoapUI, GitLab CI/CD, Kubernetes, Docker, Spring, Java, Mockito, Microservices Architecture, IntelliJ IDEA, Slack, APIs, REST APIs, Web Services, Continuous Delivery (CD), Continuous Integration (CI), OAuth 2, Node.js, Containers, Telecommunications, SCSS, Less, Front-end

Intermediate Full-stack Software Developer

2017 - 2018

IBM

Contributed to two applications in the banking industry's compliance division for compliance officers to determine or report if a transaction will cause income gain or loss. The application was developed in Jakarta EE, OracleDB, PL/SQL, and JSP.
Redesigned the web interface and added additional functionalities. Changed the way files were integrated into the application. Created a new module that automated the manual working process to bring stock data information into the application.
Met deadlines, provided deployment support when needed, and assisted the client in unlocking certain blocking points for the project.

Technologies: SQL, Full-stack, Java, PL/SQL, Oracle Database, JavaScript, CSS, JDBC, Jakarta Server Pages (JSP), Java EE, Oracle, Stock Market, Web Services, OAuth, Stock Trading, Banking & Finance

Junior Full-stack Software Developer

2016 - 2017

UniCredit

Worked on a web application that facilitates file sharing between UniCredit and OeNB (Österreich Nationalbank). This application generates, edits, and converts reports from XLS format to XML format.
Developed a new web module where users can add, edit, and archive the released documentation for a software product. The product was developed with Java 8, IBM Db2, and Vaadin.
Tracked and fixed bugs using Jira as a reporting tool. Participated in Agile meetings and understood the clients' needs and requirements.

Technologies: SQL, Full-stack, JavaScript, Java 8, Java, jQuery, CSS, IBM Db2, Vaadin, JPA, Hibernate, Spring, Jakarta Server Pages (JSP), Java EE, Oracle, Mockito, IntelliJ IDEA, APIs, REST APIs, Web Services, Banking & Finance, Front-end

Junior Full-stack Software Developer

2015 - 2016

Clarisoft Technology

Worked on a clinical trial management system (CTMS) designed to accommodate regulatory compliance and enhance clinical research operations. The products are for the healthcare industry and developed with C#, .Net, SQLServer, and Telerik.
Developed and redesigned some functionality of the application based on the documentation. Redesigned the user interface based on the received documentation.
Created a cross-mobile social media application with NET. Xamarin and C#. The platform brings on the same application of all the social media platforms to facilitate following celebrities.

Technologies: SQL, Full-stack, Telerik, Xamarin, CSS, jQuery, Microsoft SQL Server, Web Forms, ASP.NET, C#, APIs, REST APIs, Web Services

Experience

Travelers

A social web platform created for travelers around the world to create content and share their experiences from a particular trip. The platform is meant to be easy to scale horizontally and fault-tolerant, with high availability in a microservices architecture. It was developed using JHipster, Spring Boot, Java 11, React, Apache Kafka, Redis, Elasticsearch, Gatling, Cucumber, OpenAPI, MongoDB, and Docker and deployed to AWS.

Money Management Platform

A platform that provides a simple way to deal with personal finances—income, expenses, and savings. It was developed with a microservices architecture using the following technologies: Java 8, Gradle, Spring Boot, Spring Cloud, Angular 5, Docker, and MongoDB.

Clinical Management Project

A project designed for private clinics to help them manage patients and appointments. It was developed with a microservices architecture using the following technologies: Java 8, Gradle, Spring Boot, Spring Cloud, Angular 5, Docker, and MongoDB.

Transforming How We Diagnose Heart Disease

I developed this project as my degree thesis. The purpose was to find new ways to determine whether a person has a heart condition or not, using radiology images and an artificial neural network trained on those images. The project was developed using Python 3.6 and TensorFlow library.

Jobzz

This platform has been designed to simplify communication between employers and freelancers. It was an excellent opportunity for me to expand my knowledge of the following technologies: Java 8, Spring Boot, Spring Security, MySQL, AngularJS, Maven, and SASS.

Education

2013 - 2017

Bachelor's Degree in Computer Engineering

University of Bucharest - Bucharest, Romania

Certifications

APRIL 2022 - PRESENT

AWS Partner: Accreditation (Technical)

Amazon Web Services Training and Certification

Skills

Libraries/APIs

JDBC, REST APIs, TensorFlow, jQuery, React, Stripe, Node.js, Stripe API

Tools

Apache Maven, IntelliJ IDEA, Gradle, Apache Tomcat, SoapUI, Cucumber, Git, GitLab CI/CD, Slack, Jenkins, Amazon EKS, Terraform

Languages

Java, SQL, Java 11, JavaScript, TypeScript, CSS, Python, Scala, C#, Java 8, SCSS, Less

Frameworks

Spring, Hibernate, Mockito, Spring Boot, Angular, Selenium, JPA, Angular Material, OAuth 2, Spring Security, AngularJS, Apache Spark, Hadoop, ASP.NET, Jakarta Server Pages (JSP), Vaadin, GWT, Redux

Paradigms

Microservices Architecture, Agile, DevOps, Microservices, Continuous Delivery (CD), Continuous Integration (CI), Scrum

Storage

MySQL, MongoDB, Cassandra, Redis, Elasticsearch, Web Forms, Microsoft SQL Server, IBM Db2, PL/SQL, PostgreSQL, Amazon S3 (AWS S3)

Platforms

Oracle, Docker, Linux, OpenShift, Kubernetes, Apache Kafka, Amazon Web Services (AWS), MacOS, Xamarin, Java EE, Oracle Database, Telerik, Amazon EC2

Industry Expertise

Trading Systems, Banking & Finance, Telecommunications

Other

Full-stack, APIs, Web Services, CI/CD Pipelines, Front-end, Stock Market, OAuth, Containers, Spring Cloud, Stock Trading, Amazon RDS

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