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Can I code Hotjar?

Heatmaps and session recordings both come from the same trick: log DOM mutations and mouse/scroll events, replay them later. That trick is well-documented and open-source libraries already do the hard part — the weekend goes into storage and a decent playback UI.

VIBE SCORE 93/100

how this is worked out

Why CanICodeThis says Borderline

  • Recording mouse movement, clicks, and scroll position as a timestamped event stream is a solved pattern
  • Replaying that stream against a snapshot of the page (via DOM mutation recording) has mature open-source libraries behind it
  • Click-position heatmaps are just an aggregation of click coordinates rendered as a density overlay

Read before building

  • Recordings at real traffic volume generate a lot of data fast — storage and retention policy need real thought
  • Masking sensitive fields (never record what someone typed in a password or card field) has to be correct, not just present
  • Their survey and feedback-widget features are a second product bolted onto the recording engine

Bill of materials

The parts this build actually needs, each rated on its own — the average is the Vibe Score above.

Landing page99
CRUD database95
Search86

The build spec

Build me a session recording and heatmap tool: a small JS snippet that records DOM mutations, clicks, and scroll position (using an existing DOM-recording library, not hand-rolled), sends the event stream to a storage endpoint, and a playback UI that replays a session like a video. A click heatmap view aggregating click coordinates across sessions on the same page. Automatically mask input fields marked as sensitive.
categoryanalytics
time to codea weekend
Borderline
their price$32/mo · $384/yr
last checked2026-08 · source ↗

Questions

Can I code Hotjar?

Borderline. Heatmaps and session recordings both come from the same trick: log DOM mutations and mouse/scroll events, replay them later. That trick is well-documented and open-source libraries already do the hard part — the weekend goes into storage and a decent playback UI.

How much does Hotjar cost?

Hotjar costs $32/mo (about $384/yr) as of 2026-08. That's what a working rebuild would save you.

What do I lose by building it myself?

Recordings at real traffic volume generate a lot of data fast — storage and retention policy need real thought Masking sensitive fields (never record what someone typed in a password or card field) has to be correct, not just present Their survey and feedback-widget features are a second product bolted onto the recording engine

Is there a free alternative to Hotjar I don't have to build?

Yes — PostHog, OpenReplay are open-source options worth trying before you build your own. Details are in the standard parts section on this page.