diff --git a/core/templates/partials/compose-panel.html b/core/templates/partials/compose-panel.html
index ef56c70..b7eaeee 100644
--- a/core/templates/partials/compose-panel.html
+++ b/core/templates/partials/compose-panel.html
@@ -257,6 +257,14 @@
           <div class="compose-source-badge-wrap">
             <span class="compose-source-badge source-{{ msg.source_service|default:'web'|lower }}">{{ msg.source_label }}</span>
           </div>
+          {% if msg.block_gap_display %}
+            <p
+              class="compose-block-gap"
+              title="Time since previous message in this sender block">
+              <span class="icon is-small"><i class="fa-regular fa-hourglass-half"></i></span>
+              <span class="compose-block-gap-val">{{ msg.block_gap_display }}</span>
+            </p>
+          {% endif %}
           {% if msg.image_urls %}
             {% for image_url in msg.image_urls %}
               <figure class="compose-media">
@@ -462,6 +470,20 @@
     justify-content: flex-start;
     margin-bottom: 0.36rem;
   }
+  #{{ panel_id }} .compose-block-gap {
+    margin: -0.12rem 0 0.26rem;
+    display: inline-flex;
+    align-items: center;
+    gap: 0.22rem;
+    font-size: 0.64rem;
+    line-height: 1.1;
+    color: #5f6c7d;
+    opacity: 0.95;
+  }
+  #{{ panel_id }} .compose-block-gap-val {
+    font-weight: 700;
+    letter-spacing: 0.01em;
+  }
   #{{ panel_id }} .compose-source-badge {
     font-size: 0.84rem;
     padding: 0.12rem 0.5rem;
@@ -1815,6 +1837,22 @@
         badgeWrap.appendChild(badge);
         bubble.appendChild(badgeWrap);
       }
+      if (msg.block_gap_display) {
+        const blockGap = document.createElement("p");
+        blockGap.className = "compose-block-gap";
+        blockGap.title = "Time since previous message in this sender block";
+        const icon = document.createElement("span");
+        icon.className = "icon is-small";
+        const i = document.createElement("i");
+        i.className = "fa-regular fa-hourglass-half";
+        icon.appendChild(i);
+        const value = document.createElement("span");
+        value.className = "compose-block-gap-val";
+        value.textContent = String(msg.block_gap_display || "");
+        blockGap.appendChild(icon);
+        blockGap.appendChild(value);
+        bubble.appendChild(blockGap);
+      }
       const imageCandidatesFromPayload = Array.isArray(msg.image_urls) && msg.image_urls.length
       ? msg.image_urls
       : (msg.image_url ? [msg.image_url] : []);
@@ -1858,7 +1896,7 @@
         icon.appendChild(i);
         const timeSpan = document.createElement("span");
         timeSpan.className = "compose-tick-time";
-        timeSpan.textContent = String(msg.read_display || "");
+        timeSpan.textContent = String(msg.read_delta_display || "");
         tickWrap.appendChild(icon);
         tickWrap.appendChild(timeSpan);
         meta.appendChild(document.createTextNode(" "));
@@ -1874,7 +1912,7 @@
         icon.appendChild(i);
         const timeSpan = document.createElement("span");
         timeSpan.className = "compose-tick-time";
-        timeSpan.textContent = String(msg.delivered_display || "");
+        timeSpan.textContent = String(msg.delivered_delta_display || "");
         tickWrap.appendChild(icon);
         tickWrap.appendChild(timeSpan);
         meta.appendChild(document.createTextNode(" "));
diff --git a/core/views/compose.py b/core/views/compose.py
index 60cb3d6..b5e00b2 100644
--- a/core/views/compose.py
+++ b/core/views/compose.py
@@ -730,6 +730,8 @@ def _serialize_messages_with_artifacts(
     for item in serialized:
         item["gap_fragments"] = []
         item["metric_fragments"] = []
+        item["block_gap_ms"] = None
+        item["block_gap_display"] = ""
 
     counterpart_identifiers = set(counterpart_identifiers or [])
     snapshot = (
@@ -749,6 +751,17 @@ def _serialize_messages_with_artifacts(
         current_outgoing = _message_is_outgoing_for_analysis(
             msg, counterpart_identifiers
         )
+        if (
+            prev_msg is not None
+            and prev_ts is not None
+            and prev_outgoing is not None
+            and current_outgoing == prev_outgoing
+            and current_ts >= prev_ts
+        ):
+            block_gap_ms = current_ts - prev_ts
+            serialized[idx]["block_gap_ms"] = int(block_gap_ms)
+            serialized[idx]["block_gap_display"] = _format_gap_duration(block_gap_ms)
+
         if (
             prev_msg is not None
             and prev_ts is not None