Chris is available for hire

Chris Zhang

Verified Expert in Engineering

Software Engineer and Developer

Location

Ontario, CA, United States

Toptal Member Since

August 23, 2023

Chris is a senior back-end Java developer with almost ten years of experience building efficient, scalable back-end services for eCommerce sites and the healthcare industry. He is also a fast learner with a deep knowledge of Java, Spring Boot, RESTful APIs, and microservices architecture. Chris is also proficient at implementing secure authentication and authorization mechanisms, ensuring data integrity and protection, and leveraging his strong analytical and problem-solving skills.

Back-end RESTful Web Services Java Databases Spring Java 8 Spring Boot Docker Amazon Web Services (AWS)Git REST APIs Elasticsearch AWS Glue PySpark Python Enterprise Java Beans (EJB)SoapUI MyBatis JCL

Portfolio

Shoobilee, Inc.

Spring Boot, RESTful Web Services, Chase Paymentech, PostgreSQL, Amazon EC2...

Akido Labs

Java 8, RESTful Microservices, HL7 FHIR Standard, AWS Glue, Apache Airflow...

Unitedstars International Ltd.

Spring, RESTEasy, MyBatis, MySQL, Elasticsearch, Amazon EC2, Redis...

Experience

Spring - 7 years Java 8 - 7 years RESTful Web Services - 7 years CI/CD Pipelines - 6 years Docker - 5 years Elasticsearch - 4 years Python - 2 years HL7 FHIR Standard - 2 years

Availability

Part-time

Preferred Environment

Shell, Windows, Slack, IntelliJ IDEA, Postman, SoapUI, Mirth Connect, AWS Glue, AWS Lambda, GitLab CI/CD

The most amazing...

...back-end service I've created from scratch is for Yamibuy's eCommerce site, one of the most successful apps in Asia.

Work Experience

Senior Java Software Engineer

2022 - 2023

Shoobilee, Inc.

Built a Java RESTful web service using Spring Boot, PostgreSQL, and Redis.
Implemented a payment system by integrating PayPal, Chase Paymentech Orbital Gateway, and a customer subscription system.
Wrote a shell script to deploy the back-end service to Amazon EC2.

Technologies: Spring Boot, RESTful Web Services, Chase Paymentech, PostgreSQL, Amazon EC2, Amazon Route 53, Redis, Java, Amazon Web Services (AWS), Back-end, Databases, Git, REST APIs

Senior Java Software Engineer

2019 - 2022

Akido Labs

Maintained a Java RESTful web service providing healthcare information based on the HAPI FHIR library. I introduced new features, endpoints, and bug fixes.
Managed an ETL pipeline using AWS Glue with PySpark and Apache Airflow with Python. I also leveraged Amazon CloudWatch for monitoring purposes and AWS Lambda to trigger the AWS Glue jobs and move files to FTP and Amazon S3.
Supported a data pipeline using Mirth Connect by JavaScript.
Built a NestJS common package for connecting and using RabbitMQ as a message queue service.

Technologies: Java 8, RESTful Microservices, HL7 FHIR Standard, AWS Glue, Apache Airflow, Mirth Connect, RabbitMQ, NestJS, PySpark, Python, Shell Scripting, PostgreSQL, Couchbase, Amazon S3 (AWS S3), Amazon DynamoDB, GitLab CI/CD, Jenkins, CircleCI, Docker, Terragrunt, Amazon CloudWatch, Amazon Web Services (AWS), TypeScript, Infrastructure as Code (IaC), Back-end, Databases, Git, REST APIs

Senior Java Developer and Team Leader

2016 - 2019

Unitedstars International Ltd.

Designed and built the RESTful web service from scratch with Spring, RESTEasy, MyBatis, and MySQL to distribute to ctrip.com and Alibaba.
Managed the project's progress and coordinated the team's daily work, coding the central part of the system and reviewing code from members' pull requests.
Developed and designed a responsive and efficient search system using Elasticsearch.
Handled the static data integration of several hotel providers, including data mapping, and integrated APIs from popular hotel providers into our hotel system.
Built the cache system using Redis for a better user experience.

Technologies: Spring, RESTEasy, MyBatis, MySQL, Elasticsearch, Amazon EC2, Redis, Amazon Web Services (AWS), Back-end, Databases, Git, REST APIs

Senior Software Engineer

2015 - 2016

Yami

Designed and built the RESTful service for Yamibuy, a popular online shopping website, fitting it into dynamic usages for mobile and web applications and leveraging Spring Boot, MyBatis, and MySQL.
Built a payment service for Yamibuy by integrating it with Chase Bank's gateway and PayPal.
Created an intelligent and fast search service with Elasticsearch for many products in several categories.
Developed a distributed system using NGINX as the load balancer and MySQL for replication.
Implemented a read-and-write split and a master-slave sync system, using AWS for web service deployment and website hosting and Apache Kafka as a messaging system.

Technologies: Spring Boot, MyBatis, RESTful Services, MySQL, Amazon EC2, NGINX, Elasticsearch, Chase Paymentech, Apache Kafka, OAuth, Amazon Web Services (AWS), Back-end, Databases, Git, REST APIs

Senior Software Engineer

2013 - 2014

CIeNET Technologies

Participated in developing and maintaining a B/S network system made by Ericsson. This system evolved into two distinct approaches to managing network elements made by different manufacturers, such as Redback and Marconi.
Implemented a JBoss application server using Java EE and Enterprise Java Beans (EJB) technology to manage the end-to-end service and communication over various network elements.
Gained experience in the Spring framework and CI/CD pipelines.

Technologies: Java, IP Networks, Network Management Stations (NMS), Enterprise Java Beans (EJB), Spring, CI/CD Pipelines

Software Developer

2005 - 2013

Beijing JBridge Information Technology

Acted as a design leader, managing a team of ten members.
Developed a major module for a web management system, transforming it from Apache Struts and Oracle into a new system based on Seam, MyBatis, and NonStop.
Built a management system for supermarket stock and designed a batch system using shells, scripts, and SQL. Handled code design, code development, and function testing.
Participated in maintaining a client-server management system for some hospitals based on VB.NET, handling code development and testing.
Contributed to developing a logistics system based on Java EE using JSP, C, JCL, and Oracle databases. Handled preliminary design, detailed design, test case design, code development, and function testing.
Maintained a logistics system based on COBOL, handling preliminary design, detailed design, test case design, code development, function testing, technical support, and training.

Technologies: COBOL, VB.NET, Java, Hibernate, Java EE, MyBatis, Seam, SQL, C, JCL

Experience

A RESTful Back-end Service for Yamibuy

https://www.yamibuy.com/

A RESTful back-end service and search engine that I designed and built from scratch for Yamibuy, a famous Asian online shopping website. I fitted it into dynamic usages for mobile and web applications, using Spring Boot, MyBatis, and MySQL.

A Data Pipeline for a Healthcare Group

A data pipeline I built for processing healthcare information. It was developed from scratch using AWS Glue with PySpark and Apache Airflow with Python to transform the healthcare data. I also used Amazon CloudWatch for monitoring purposes and AWS Lambda to deliver the data to FTP and Amazon S3.

A Search Engine for Yamibuy

https://www.yamibuy.com/

After the fast growth of the quantity of the products, we needed to optimize the search engine. So, I introduced Elasticsearch in our architecture for the fast searching response of our astronomical products in many different categories.

Skills

Languages

Java, COBOL, Java 8, C#, Python, C++, VB.NET, SQL, C, TypeScript

Frameworks

Spring, Hibernate, Spring Boot, NestJS, Seam

Libraries/APIs

Mirth Connect, RESTEasy, REST APIs, MyBatis, PySpark, Terragrunt

Tools

Shell, IntelliJ IDEA, Postman, SoapUI, AWS Glue, GitLab CI/CD, Git, RabbitMQ, Slack, NGINX, Apache Airflow, Jenkins, CircleCI, Amazon CloudWatch, JCL, Kibana

Paradigms

HL7 FHIR Standard

Platforms

Windows, Java EE, Amazon EC2, Docker, Amazon Web Services (AWS), AWS Lambda, Apache Kafka, Oracle

Storage

Elasticsearch, PostgreSQL, Databases, MySQL, Couchbase, Amazon DynamoDB, Amazon S3 (AWS S3), Redis

Other

CI/CD Pipelines, RESTful Services, RESTful Web Services, Back-end, RESTful Microservices, Shell Scripting, IP Networks, Network Management Stations (NMS), Enterprise Java Beans (EJB), Chase Paymentech, OAuth, Amazon Route 53, Computer Science, FTP, Infrastructure as Code (IaC)

Education

2001 - 2005

Bachelor's Degree in Computer Science

Hebei University of Technology - Hebei, China

Collaboration That Works

How to Work with Toptal

Toptal matches you directly with global industry experts from our network in hours—not weeks or months.

Share your needs

Discuss your requirements and refine your scope in a call with a Toptal domain expert.

Choose your talent

Get a short list of expertly matched talent within 24 hours to review, interview, and choose from.

Start your risk-free talent trial

Work with your chosen talent on a trial basis for up to two weeks. Pay only if you decide to hire them.

Top talent is in high demand.

Start hiring