Create browser extension chrome/firefox

Hello, I am looking for someone for my project. I would like to have a browser extension/toolbar (Firefox, Chrome) programmed that compares the item immediately when shopping online and displays the cheaper price. a similar plugin is the follow

https://addons.mozilla.org/de/firefox/addon/ciuvo

https://chromewebstore.google.com/detail/ciuvo-price-comparison/cbmmkkbjmcidpennbibfkncodjenfpjh?hl=de&pli=1

see you soon, Markus