stency using <strong>Feature Groups</strong> with TTL-based expiry.</li>
<li>A hybrid schema was used: feature keys stored in <strong>ZooKeeper</strong>, data stored in <strong>compact arrays</strong>.</li>
</ul>
<h3 class="anchor anchorWithStickyNavbar_LWe7" id="3-interaction-store---0th-version">3. Interaction Store - 0th Version<a href="#3-interaction-store---0th-version" class="hash-link" aria-label="Direct link to 3. Interaction Store - 0th Version" title="Direct link to 3. Interaction Store - 0th Vers