List of free site-reaction stuff for developerππ½
If you're looking for all programming tools around site-reaction (not just free). Check this page List of site-reaction Programming Tools

Lyket
Lyket is the simplest tool to receive immediate feedback, with like buttons that respect your visitors privacy
Tag: site-reaction
Test Up to 500 pageviews per month *

Freddy Feedback
A simple and powerful tool to get feedback from your customers. Get feedback on your product features, onboarding, pricing, marketing content, FAQs and more.
Tag: site-reaction
RESPONSES 1000 per month
USAGE in Unlimited websites Unlimited surveys Unlimited users