After watching the drone footage of San Francisco in burning orange skies due to wildfires, with the Blade Runner soundtrack playing on top of it, I decided to look for an engagement with a company helping to do something to address climate change. This is how I learned about Leap Energy which provides solutions for connecting distributed energy resources to wholesale energy markets in order to make the electric grid more resilient.

In the role of Technical Lead I focused on projects in the following two areas:

• infrastructure modernization
  • migration of the self-hosted customized VPN server to a cloud offering (vendor selection, user migration)
  • migration of the self-hosted Kafka cluster to Confluent Cloud (vendor selection, data migration, integration with the monitoring system, service migration and coordinated roll-out)
  • migration of the self-hosted elasticsearch cluster to elastic cloud (vendor selection, data migration, service migration, coordinated roll-out)
• microservice architecture modernization
  • introduction of in order to document architecture decisions
  • introduction of GRPC as a means for service-to-service communication (replacing direct database access across services and an experimental service-to-service communication via Kafka topics) between Spring Boot services
  • development of a service protocol registry and distribution mechanism (based on protocol buffers) to allow contract-first design and development of the various services
  • introduction of Gradle with Kotlin support as a build tool as a replacement to maven and porting multiple services
  • introduction of jOOQ as a replacement to Hibernate for database access

• review of the technical design of a single-node Akka application against the business objectives
• support of the project team with regard to questions and issues arising during the project with regard to the usage of Akka and Scala

• Architecture evaluation of an event-sourced system based on Apache Kafka and Kubernetes

• Troubleshooting performance issues with an Order Management System (based on Akka Cluster, Kafka and Kubernetes) and setting up a large-scale load test for the system

• The onboarding of a new strategic client on the Paidy platform brought with it stricter latency requirements (in order to meet the agreed-upon Service Level Agreement)
• The backend application built on top of Akka Cluster with cluster sharding did not deliver consistent latency in redeployment and failover scenarios
• I helped the engineering team find and understand the root cause of the latency fluctuations and guided them throughout the process of implementing a solution

Ongoing support of the engineering teams working on the next generation of the PSP (Payment Services Provider) core platform:

• architecture reviews
• design and code reviews
• performance engineering workshops

• A core application based on Akka Cluster had ongoing memory issues, requiring to run virtual machines with a lot of memory (64+ GB) as a workaround
• I held a performance engineering workshop to show the team how to use the adequate tooling for performance profiling and memory pressure analysis
• A key result of the workshop was a tenfold decrease of the JVM memory required to run the project

• I joined the Payment Services team at MOIA to help with developing the second version of the payment system based on Scala and Akka
• The system needed to enable the payment of MOIA trips and needed to integrate with multiple Payment Service Providers while providing strong consistency as well as being highly available

• Development of a template project for deploying Akka Cluster projects with Kubernetes

I supported the engineering team during the initial development of the SILO platform (based on Akka Cluster and Scala) by:

• reviewing the system architecture and technical feature designs
• providing guidance and best practices with regard to the use of Akka Cluster, Scala and Kubernetes
• developing the initial project scaffold and core application layer

• Evaluation of the deployment of a split-brain resolution solution for Akka Cluster deployed with Kubernetes on Amazon Web Services (AWS)
• At this time, there was no official support for Kubernetes deployments of Akka and therefore I proceeded to analyze the deployment model with regard to different edge-cases that could occur in a split-brain scenario

• Architecture review and code review of an Akka Cluster based application

• architecture of the new microservice-based software platform for an existing real-time communication platform
• design and code reviews
• hands-on development of the core feature set of the platform (based on Akka, Scala and Scala.js)

• This engagement was a direct result of my work on deploying Akka on the Raspberry PI
• VCharge developed an embedded system and software solution to help address the issue of maintaining the stability of the electric grid in the presence of increasing renewable generation
• During this engagement I supported VCharge in building a new version of the low-latency backend service (based on Akka) responsible for aggregating telemetry as well as actuating the IoT devices at the core of the VCharge Grid network

DIMOCO initially approached me in order to develop a prototype for an architecture evaluation with Akka Cluster to help make a decision of which technology to use (the other contending technology was VertX). I developed a software prototype deployed on multiple Raspberry PIs to demonstrate the resilience and failover capability of Akka Cluster (unplugging a network cable while transactions were being executed and showing that the processing continues and no transaction is failing makes for a good demonstration).

Akka Cluster was subsequently selected as the technology to use for developing the new version of DIMOCO?s SMS delivery platform. I supported the engineering team in the early stages of the development of the platform by:

• reviewing the architecture and the technical design
• regularly reviewing the code
• providing guidance and best practices with regard to the use of Akka and Akka Cluster

Nexxchange provides an all-in-one platform for managing Golf resorts and hotels.

I designed and implemented the online portal that aggregates the tee times of the multiple golf clubs, making them searchable and bookable.