Mikael Henriksson

Senior Software Developer and Designer

Skills

Languages:

Ruby, Lua, JavaScript, HTML, CSS, SQL, pSQL, ShellScript (bash fish)

Frameworks:

Ruby on Rails, RSpec, Sidekiq, Hotwired, Turbo, PostgreSQL, StimulusJS, TailwindCSS

Databases:

Redis, PostgreSQL, MySQL, MariaDB

Tools:

Docker, git, GitHub, Dokku, Terminal, Continuous Integration

Projects

Sidekiq Unique Jobsgithub.com/mhenrixon/sidekiq-unique-jobs

Ruby, Redis, Lua, Sidekiq

Prevents duplicate sidekiq job with a fancy redlock mechanism
Uses Lua scripts for performance
Been supporting it since July, 2012 when I extracted it from Sidekiq
Object oriented code base that is a pleasure to work with

Experience

HL Design & Media AB, Växjö, Sweden

2022 - Current

Remote (Employment) Senior Fullstack Developer

Upgrading Ruby on Rails from 4.1 to 6.1
Performance improvements across the entire stack.
ERP system integrations with Fortnox, Pyramid Pro Client.
Integrated with Klarna Settlements.
Reduced memory usage with 60+ percent by switching to Jemalloc.
Parallelization of background jobs.
Implemented monitoring and APM using AppSignal.
Reduced page load times by setting up cloudfront distributions for both rails assets and Amazon S3.

Pitchfish Inc, Richardson, TX, USA

2021 - Current

Remote (Founder) Senior Fullstack Developer

Greenfield rails 7.0 project using all the new rails technologies
Implemented design using TailwindCSS 3.0, Stimulus JS and Ruby on Rails 7.0 and the latest hotwire and turbo-rails for partial page updates.
Built all the initial frontend using aforementioned technologies and created a UX framework onto of TailwindCSS 3.0
Inbound and outgoing emails implementation using Postmark
Payment integration with Stripe Connect for buyers to reimburse them for their time
Payment integration with Stripe Checkout Express to allow sellers to put the money down for a pitch.
PostgreSQL for database
Redis and Sidekiq for background job processing

Nalantis, Belgium, Antwerp

2021 - Current

Remote (Contract) Senior Fullstack Developer

Greenfield rails 7.0 project using all the new rails technologies
Implemented design using TailwindCSS 3.0, Stimulus JS and Ruby on Rails 7.0 and the latest hotwire and turbo-rails for partial page updates.
Built all the initial frontend using aforementioned technologies and created a UX framework onto of TailwindCSS 3.0

mhenrixon Consulting, Blankenburg (Harz), Germany

2018 - Current

Remote (Founder) Senior Backend Developer

See all the various remote freelancing roles during this time period

HL Design & Media AB, Växjö, Sweden

2023 - 2024

Remote (Contract) Senior Fullstack Developer

Joint Academy, Malmö, Sweden

2020 - 2021

Remote (Contract) Senior Backend Developer

Upgraded the monolith to Rails 6.1.
Implemented backend for video calls, scheduled calls and call center functionality for the US market using Twilio.
Implemented custom state machines for video calls
Upgraded ruby from 2.6.1 to 2.7.2
Upgraded all the hundreds of other dependencies (ruby gems) in the monolith
Reduced production docker image size from 1,6 GB to 395 MB
Dockerized development environment, sprinkling that little Makefile magic on top of docker.
Improved test suite performance (inside docker) from 80+ minutes to ~12 minutes
Designed and built out an event-driven micro service architecture template with RabbitMQ for messages.

Wundertax Gmbh, Berlin, Germany

2020 - 2020

Remote (Contract) Fullstack Developer

Instrumental in migrating all ruby services from Gitlab, CircleCI and DEIS to GitlabCI and Kubor/ Kubernetes.
Implemented various new rules for the tax year 2019
Streamlined the development environment for all services using Docker with a little Makefile magic to create some external dependencies
Extracted core business logic from ruby gems and monolith into several new rails services
Improved testing reliability and code coverage
Upgraded all services to Rails 6.1 and Ruby 2.7.2

solarisBank AG, Berlin, Germany

2018 - 2019

Remote (Contract) Senior Backend Developer

Extracted person identifications from monolith into new service
Migrated to new person identifications service with close to zero downtime
Developed core functionality on PSD2 initiative (open banking)
Developed partner invoicing for person identifications
Developed customised signing endpoint

ProSiebenSat.1, Munich, Germany

2018 - 2018

Remote (Contract) Senior Backend Developer

Stabilisation of all systems
Developing structured logging
Setting up continuous integration
Setting up continuous delivery
Standardisation of processes
Rolled out a mongodb cluster
Developed an automated mongodb backup system

solarisBank AG, Berlin, Germany

2017 - 2018

Remote (Contract) Senior Backend Developer

Part of building a fully autonomous agile team.
Contributed greatly in overall improvements of everything from how docker is used to improving build times, test times, reliability of tests to how the team worked together.
Developed a service to handle data change requests (part of the core banking offering).
Developed a feature flags solution.
Developed an IBAN lookup and validation service.
Developed a service for screening people for PEP hits.
Developed functionality for statement of accounts.
Developed functionality for bank statements.
Developed functionality for standing orders.
Developed functionality for dealing with account limits.

Zoolutions AB,, Landsbro, Sweden

2007 - 2018

Remote (Founder) Senior Backend Developer

See all the various remote freelancing roles during this time period

Reevoo Ltd, London, England

2016 - 2017

Remote (Contract) Senior Backend Developer

Performance and scalability improvements to the systems that handle grouping of product reviews
Designed and implemented a logging, monitoring and alerting system for standardized logging (See https://github.com/reevoo/sapience-rb for more info)

Kisko Labs, Helsinki, Finland

2014 - 2017

Remote (Contract) Fullstack Developer

Implemented recurring card payments for PRO Accounts with Stripe
Ongoing performance optimizations
Upgraded Ruby on Rails from 3.2 to 4.2
Implemented Gym membership billing with Stripe

Cubits, Berlin, Germany

2016 - 2016

Onsite (Employment) Senior Backend Developer

Integrations with third party payment systems.

Crealytics GmbH, Berlin, Germany

2015 - 2016

Onsite (Employment) Senior Backend Developer

Improved Continuous Delivery by creating a true pipeline using Jenkins and Jenkins Workflow
Designed and implemented a Message Bus using Kafka on Apache Mesos
Improved the local workflow with docker-compose
Implemented NewRelic monitoring for all microservices recording cross application transactions
Designed a reverse proxy/api gateway using Kong
Designed the backend implementation of an activity feed

Hero Gaming AB, Malmö, Sweden

2013 - 2015

Remote (Contract) Senior Backend Developer

Designed and implemented payment transactional system; a scalable design created with the intent that newer and less experienced developers could access and change without effecting performance or extendability
Automated server provisioning using chef
Developed full test coverage for server configuration for both unit and integration tests
Optimized CasinoSaga API to serve up to 2500 requests per minute on a single physical host
Optimized the seamless wallet servers to respond in average 100-200ms per money transaction
Developed API integrations from AngularJS to said API
Developed integrations with gaming providers in AngularJS

Form26 Ltd, Richardson, TX, USA

2011 - 2014

Remote (Founder) Fullstack Developer

Created http://taskk.it using Ruby on Rails, PostgreSQL a program that automatically fills allotted “time to spend on tasks” based on custom algorithms (patent pending)
Created http://wodstack.com using Ruby on Rails, PostgreSQL and and Elastic Search. WODstack was later sold to a Finnish company (Kisko Labs) and all customers migrated to WODconnect http:// www.wodconnect.com

HL Design & Media AB, Växjö, Sweden

2012 - 2013

Remote (Employment) Senior Fullstack Developer

Developed a highly scalable localization backend for the flagship WM3
Optimized server processing times approximately 75% for WM3
Developed a widget based intranet using AngularJS

Arne Johanssons Fastighetsservice AB, Lammhult, Sweden

2007 - 2013

Remote (Contract) Fullstack Developer

Designed and developed an invoice management system using .NET 2, NHibernate and SQL Reporting Services for BI and invoice generation, installed on customer’s private machine running in UltiDev Cassini Web Server

Evry One, Växjö, Sweden

2011 - 2012

Remote (Employment) Senior Software Developer

System developer on Jeeves
Developed a mobile web application for internet explorer mobile / windows ce 5
Onsite SQL performance optimizations for customer located in central Manhattan, New York

Play'n GO, Växjö, Sweden

2010 - 2011

Remote (Employment) Senior Software Developer

Developed a Ruby-on-Rails e-commerce system for Opticians reseller with focus on ease of use for placing orders
Designed and developed a security system for a Windows Form app with corresponding WCF service
Integrated payment solutions and game providers into existing backend system to provide PNG’s customers required payment options
Upgraded existing web application to .NET 4, NHibernate 3, and MVC 3
Developed an integration with ATG into existing backend systems
Set up continuous integration environment with possibility of 1-click deployments and upgraded to .NET 4.0
Developed payment and shipping modules for a PHP e-commerce application
Managed various required upgrades and major maintenance tasks for proper scalability
Designed SMS billing application to build away errors from current system
Created a 3-tier subscription based app for mobile applications and web applications

Numo Solutions AS, Oslo, Norway

2008 - 2010

Onsite (Employment) Senior Software Developer

Substitute CTO / Tech Lead (February – May 2009) of a company rebranding project
Designed and developed billing system, a CMS for mobile web, and upgraded core projects from .NET1,0 to .NET 3.5, and a highly scalable enterprise contact backup system
Migrating/upgrading the production database from MS SQL Server 2005 to MS SQL 2008 to make use of CDC to push data to a separate reporting environment

C. Gunnarssons Verkstads AB, Vislanda, Sweden

2007 - 2008

Remote (Employment) Software Developer

System design and development when upgrading one of CGV’s old customers from using a VB6 application to control their saw mill to use a new .NET app with thin clients running a remote app on a Windows 2008 Server instance

Wadley Enterprises, Brisbane, Australia

2005 - 2007

Onsite (Employment) Fullstack Developer

Design and developed an online based purchase order system
Designed and developed a try & buy webshop for the system
Automated deployment for the customer at sign up
Creation of website, database, and an initial company/department and admin user