Kai Wa Chan
Verified Expert in Engineering
Software Developer
Kai is a product-focused Java back-end engineer and test enthusiast with experience in the payments and banking industry, working on mission-critical systems. At Goldman Sachs, he designed and built Kafka-based event-driven microservices to decouple lengthy business workflows, reducing onboarding time from months to ten minutes. Kai produces production-ready solutions that are functional, testable, observable, maintainable, extendable, and scalable.
Portfolio
Experience
Availability
Preferred Environment
MacOS, Windows, Git, IntelliJ IDEA
The most amazing...
...tool I've worked on is an eCommerce payment system that runs 24/7 and transacted half a million GBP sales during Black Friday in 2018.
Work Experience
Senior Team Lead Developer (Springboot and Camunda)
Ygrene Energy Fund, Inc.
- Transferred proprietary domain knowledge from the offshore Ruby on Rails development team to the product owner via Camunda BPMN.
- Coached the architect and Ruby on Rails developers on the Camunda 8 workflow development, such as Java, BPMN, and other Camunda 8 cloud services.
- Coached a DevOps engineer on Java development pipelines such as the Maven build and deploy pipeline and Dockerizing and parameterizing a Spring Boot application.
- Established the Camunda 8 Spring-Zeebe integration project base, including testing utility, capability, and workflow deployment.
- Designed and built the project funding slotting workflow and loan cost calculation workflow via Java and Camunda 8.
- Inspected and discovered major correctness and maintainability issues in Spring Boot web API for the unsecured loans product line.
Java Developer
Latch
- Implemented Dwolla integration to support standard ACH deposit and rent payments. This includes funding source imbalance handling (ACH returns), destination account management, and asynchronous notifications.
- Designed and implemented third-party lease and ledger data pipeline integration to support externalizing the rent payment service.
- Designed and implemented Stripe Checkout and multiparty payments integration to support property facility booking service.
- Implemented small front-end updates on the management and resident portal to provide rent payment user experience with Angular and React.
- Oversaw the requirement refinement, design, implementation, and testing during SDLC, working closely with corresponding parties, including the product manager, development team, security team, and QA.
Associate Software Engineer
Goldman Sachs
- Built a solution to support API and UI-driven onboarding processes to Stripe Treasury banking as a service (BaaS).
- Designed and built Kafka-based event-driven microservices to decouple lengthy business workflows, which reduced onboarding time from months to ten minutes.
- Designed and built the Camunda maker-checker workflow library and standardized the process.
- Designed and built the Camunda workflow library, handling and monitoring asynchronous acknowledgments.
- Established a behavioral testing practice and regression tool to reduce manual testing efforts.
- Researched the feasibility of a MongoDB client-side field-level encryption with Spring-data-MongoDB integration.
Software Engineer (Payments Platform)
The Hut Group
- Designed and built an API to convert custom rule expressions to trigger fraud measures (3DS, CV2) for card payments.
- Assisted a new card provider and payment 3DS 1.0 integration to enable direct card payment for specific sites to reduce transaction costs by around 2% and reduce chargebacks.
- Migrated ApplePay payment to another provider to align with the provider migration.
- Broke down and rewrote parts of a monolith toward microservices architecture to support future scaling and SaaS.
- Maintained an internal payments tool UI (payment method configuration and auditing) with AngularJS and Thymeleaf.
Experience
Client Onboarding | Transaction Banking
https://www.goldmansachs.com/what-we-do/transaction-banking/videos/digital-solutions.htmlPayments | eCommerce
https://www.thghosting.com/products/thg-commerce-platform/ACH Payment Integration | Residential Property Leasing
Loan Eligibility Checking and Slotting Process via Camunda 8
https://prequalification.ygrene.com/prequalSkills
Languages
Java, SQL, Java 11
Frameworks
Spring Boot, JUnit, Mockito, Swagger, Spring JDBC, Selenium, AngularJS, Play, gRPC, Angular, Play Framework, Spring, Hibernate
Tools
WireMock, Apache Maven, GitLab, Amazon Simple Queue Service (SQS), Git, IntelliJ IDEA, GitLab CI/CD, ActiveMQ, Kibana, Grafana, Camunda BPM, Jenkins, Terraform, Cucumber, REST Assured, Amazon Elastic Container Service (Amazon ECS), HashiCorp, GitHub
Paradigms
Object-oriented Programming (OOP), REST, Test-driven Development (TDD), Microservices, Kanban, Scrum, Continuous Integration (CI)
Other
Back-end, Workflow, Payment APIs, Message Queues, Networks, Card Payments, Finance, Digital Banking, CI/CD Pipelines, Non-blocking I/O, Zeebe
Platforms
Amazon Web Services (AWS), Apache Kafka, MacOS, Windows, Docker, Kubernetes, Linux
Storage
NoSQL, Spring Data JPA, Microsoft SQL Server, PostgreSQL, JSON, MongoDB, Databases
Libraries/APIs
PostgREST, REST APIs, API Development
Education
Bachelor's Degree in Computer Science
Cardiff University - Cardiff, Wales, UK
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