KARL VAILLANT

As a senior freelancer with experience in startups, I brought my knowledge and advices in setting the clean architecture pattern within the stack. I ramped up into the codebase in a 4h and pushed my first big optimization query reducing database query execution time by 5. I introduced some best practises in terms of development pattern and fixed some performances ou bug issues. Another tasks I had to tackle was to get rid of the bottleneck from the discord bot listening to events from more than 7,5K guilds. Thus, I made a discovery to find the best solution, I made a PoC and then developed the production ready solution to scale discord bot horizontally and vertically.

I gave advice on how to better design the architecture for the backend services to make them more reliable and scalable. Apart from this, I also worked on some web3 feature.

#nodejs #redis #postgresql #discord #web3 #solidity

In order to acquire knowledges on banking subjects and build from scratch a new online banking platform, I joined back the banking team. As a senior developer with experience in architecture design, I was in charge of designing and building from the ground the platform that will become a core banking sas. We set up a fast scalable and reliable micro-services platform in a domain driven design architecture pattern. We developed with the CQRS pattern + event sourcing within our services following the best practises.  I had to translate large business rules in the banking system into user stories and then technical detailed implementation tasks. As a senior member, my team trusted me on auditing, realising spikes on tools that would help our Dev experiences and  setting them up in our platform (like Auth0, roles management, kafka, event storage or design pattern for event replays)

#scrum #ddd #k8s #kafka #graphql #nodejs #postgresql #reactjs #banking

Commited as a lead developer for the payment services team, I’m was part of a team of 4 developers (2front, 2 backend), 1 designer and 1 product manager. My journey, consisted in helping my teammates moving forward on our payments services solution (employees expense claims reimbursements, supplier invoices, card transactions), playing for the team, taking ownership on projects and removing impediments. I developed on my own a new micro-service based on Dwolla environment (handling bank wire transfer between parties) and help the team integrate this provider in the spendesk app. While tackling multiple productions issues, I was in charge of getting my team work smoother (scrum rituals, virtual team building, technical workshop,  personal improvement session) so that we reached each of our sprint goals. Multiple successful projects were released to production (ship small & fast) thanks to my team commitment.

#scrum #kubernetes #github-actions #nodejs #postgresql #reactjs #banking #ddd #docker #es6 #swagger #micro-services

Inside the core-banking team, I worked as a senior NodeJs BackEnd developer. My team is in charge of extracting the core-banking from the monolith app and develop from scratch the new banking micro-services architectures.  I had to develop and manage the micro-services (koajs, events, swagger-doc, unit tests and REST apis) hosted on aws and deployed with terraform. I modelized some of the data structures on PostgreSQL, Redis and prepared the event-sourcing architecture to facilitate the intregation of KafKa. I built a few features on the GraphQL API (with Apollo)

In the meantime, I had to worked on the frontend app web application in ReactJs which communicate through REST and GraphQL api to the backend services.

#scrum #terraform #github-actions #nodejs #postgresql #reactjs #banking #event-driven #docker #es6 #swagger #micro-services

I developed backend services for the ios mobile App Elityz. I created some REST APIs for the mobile app and I realized automated tasks for computing operations. I had to add external services mapping. I maintained the platform up-to-date and fixed bugs on a daily basis.

#es7 #node #firebase #nosql #rest

Integrated in the IV2 marketplace team (nearly 30 engineers), I worked inside the development team as a senior backend/frontend developer and DevOps expert. My Scrum team which was compound of  one product owner, one scrum master, an agile coach and five developers was committed to the scrum framework guidelines (Sprint planning, daily meeting, sprint review & retrospective). We also used Kanban to reduce as much as possible the bugs stock. My developer job was divided into two main parts. Firstly, I worked, on a daily basis, on the sprint backlog items implementing functionalities on the product backend (es6, nodejs, moving from monolith to microservices, RESTFul APIS, JWT, mongodb, postgresql, docker) and Front (ReactJs, webpack, babel), unit tests (mocha, jest, commitizen, eshint). Secondly, I was responsible for the DevOps methods for our team and had to set up/enhance the automated build/deploy processes (CI/CD on Jenkins with groovy scripts, gitlab, ansible, docker , rancher and kubernetes) and management the platform tools (upgrade, experiments).

#scrum #devops #nodejs #postgresql #mongo #reactjs #kubernetes #rancher #ansible #docker #es6 #kanban

I developed back services for the ios mobile App Elityz. The services was developed on firebase cloud functions (push notif, automatic matches between profiles, distance calculation,etc)

#es7 #node #firebase

For this small mission, I realized a web administration application to handle mobile datas with the firebase framework and React/redux. I integrated the material-ui components to get a smoother visual user interface.

#es7 #react #redux #material-ui #firebase

Inside the operational service team, I worked as a senior NodeJs BackEnd developer for Frichti. I had to develop and manage many micro-services (koajs, websocket and REST) hosted on aws and orchestrated with kubernetes, docker. I modelize some of the data structures on PostgreSQL, Redis and RabbitMQ, Bull to be compliant with the event sourcing and CQRS. I needed to configure the CD/CI for my projects with automated tools: Jenkins, scripts, circle-ci and test-units. I also deployed some of the best practises of the codebase with eslint, docker-compose and ES6 features. On the other hand, I worked on a frontend backoffice web application in ReactJs/Redux and webpack.

#scrum #nodejs #postgresql #rabbitmq #reactjs #kubernetes #docker #es6 #rest

Mobile app development for community network for associations. Development of secure REST API endpoints with NodeJS and Express, a webAdmin interface (bootstrap, jQuery and AngularsJs), a web application PWA (web.pickasso.io) and a webportal (open.pickasso.io) . Establishment of Big Data using Couchbase and ElasticSearch. Setting up the Continuous Integration processes with unit tests, auto deployment, docker, code quality indicators, wikis, fail-over tools.

Working on this private project on GitHub using best practises et version management.

Administration and monitoring of the production platform on AWS. I developed different scripts for deployment automation and platform supervision.

#Node.js #Express #Couchbase #Amazon web services #Elasticsearch #Continuous integration #Bootstrap3 #Docker #AngularJS #Bash