Location: The Netherlands. I'm flexible with working hours, I usually work with clients from either Western Europe or the USA.
  Remote: Yes
  Willing to relocate: No, but willing to travel/visit
  Technologies: especially Ruby (including Ruby on Rails, Sinatra, and standalone applications), PostgreSQL, Ansible, Linux. Lots of others at the end of my comment.
  Résumé/CV: https://www.luitjes.it
  Email: lucas@luitjes.it 

* Have a slow web application that’s often down?

* Want to improve security and don’t know where to start?

* Have a legacy system that needs to be replaced?

* Are considering an acquisition but not sure about the technical side?

I can help with that. For example, in the past I have:

* Massively improved performance and reliability for a data visualization platform.

* Led a large effort to improve security for a cybersecurity SaaS.

* Built a micropayments system for a prominent media startup.

* Rebuilt an aging e-learning platform from scratch for a GDPR compliance SaaS.

* Conducted technical due diligence for acquisitions.

For more information: https://www.luitjes.it

Other tech I've worked with: Elixir, C#, Java (Spring/Hibernate), JavaScript, HTML/CSS/XSLT/XPATH/XSLFO, Elasticsearch, MongoDB, MySQL, Redis, Solr/Lucene, Graphite, Kibana, Grafana, Logstash, Icinga, Jenkins, Varnish, HAProxy, Pound, Nginx, Apache, Passenger, Vagrant, Docker, DCOS, Kubernetes, SSH, OpenVPN, TCP/IP, tcpdump/strace/lsof/etc, AWS (EC2, ELB/ALB, S3, CloudFront, Lambda, Batch, VPC, etc.