Money, and what free means here. Clarity is free, and Microsoft's own documentation calls it "a free service forever", with no traffic limits and no sampling, across unlimited projects. There is no upgrade path because there is nothing to upgrade to. Hotjar has a free tier and is otherwise a paid product, and its plans have historically been the place where session limits bite.
Hotjar is now sold as Contentsquare. Checked on 2026-09-04: hotjar.com redirects to contentsquare.com/hotjar and its pricing page to Contentsquare's. Existing Hotjar plans still run, and their own migration table contrasts "Hotjar Free" with "Contentsquare Free", but somebody signing up today is buying Contentsquare. If you are comparing these two because you are already unhappy about that, this is the reason and it is worth saying plainly.
Thirty days. Clarity retains data for up to thirty days. That is the real cost of free, and it decides more shortlists than price does: a heatmap you cannot go back and compare against last quarter is a different tool from one you can. If your question is "what changed since the redesign", check this row before anything else on this page.
Where the data goes. Clarity's data is stored in Microsoft's Azure cloud, and for customers in the EU it is transferred to Microsoft Corporation in the United States under standard contractual clauses. Whether that is acceptable is your call and your regulator's, but it is not the same answer as "hosted in Europe" and should not be read as one.
Consent, and a trap in it. Both store things on the visitor's device, so both need a consent banner. Since 31 October 2025 Clarity requires an explicit consent signal for visitors in the EEA, the UK and Switzerland, and Microsoft documents what happens without one: a degraded mode in which every page view starts a new session. Nothing breaks and no warning appears. The dashboard fills with numbers that are simply wrong. An EU site that installs Clarity without wiring consent properly gets exactly this, and usually finds out months later.
What each one does that the other does not. Clarity has SDKs for Android, iOS, Flutter and React Native, and reports where traffic came from. Hotjar has surveys and a feedback widget, the asking-people half, which Clarity has no equivalent of; Microsoft's own blog pairs Clarity with a third-party plugin when somebody wants surveys. So the overlap is heatmaps and recordings, and on either side of that overlap they are different products.
Openness. Clarity's capture script is published under the MIT licence on GitHub; the service behind it is not, and neither tool can be self-hosted. Hotjar is not open source in any part.