Based on our record, UX Metrics seems to be more popular. It has been mentiond 2 times since March 2021. We are tracking product recommendations and mentions on various public social media platforms and blogs. They can help you identify which product is more popular and what people think of it.
For free card sorting and tree testing (I didn't test that one personally though): https://uxmetrics.com/. Source: over 1 year ago
In case someone reads this in search of another tool, I did a search again, and found one I had missed, that actually has a usable free tier as of writing https://uxmetrics.com. - Source: Hacker News / about 2 years ago
airfocus - The first modular product management platform: Discover, learn, plan and deliver - your way.
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Proven By Users - Online Card Sorting, tree testing, first click testing and more.