Freelancers learn fast
I have worked with lots of tools, on dozens of platforms. Below is a selection of them. If yours is not in there: don't worry. Freelance developers have seen it all and they are used to getting up to speed quickly in a new environment.
Bootstrap
Grunt
Gulp
HighCharts
HTML
Javascript
jQuery
jQuery UI
LESS
Responsive
SCSS
Visual Website Optimizer
AngularJS
ASP.net
Bigcommerce
CakePHP
Contentful
CraftCMS
Magento
Outsystems
React
SEOshop
Sitecore
Vue.js
Wordpress
A/B testing
Agile
CorelDraw
Git
Jira
Node.Js
Photoshop
Scrum
Subversion
Trello
Wireframing
Balsamiq