diff --git a/LINE_DRAWING_IMPROVEMENTS.md b/LINE_DRAWING_IMPROVEMENTS.md
index 3ee21e8..799416d 100644
--- a/LINE_DRAWING_IMPROVEMENTS.md
+++ b/LINE_DRAWING_IMPROVEMENTS.md
@@ -135,7 +135,7 @@ opacity={isSelected ? 1 : 0.85}
 
 ---
 
-### Phase 4: Endpoint Dragging
+### Phase 4: Endpoint Dragging ✅ DONE
 
 #### 4.1 Drag State
 **File**: `src/components/SvgOverlay.tsx`
diff --git a/src/app/api/annotations/[id]/route.ts b/src/app/api/annotations/[id]/route.ts
index f5c8c8d..971f071 100644
--- a/src/app/api/annotations/[id]/route.ts
+++ b/src/app/api/annotations/[id]/route.ts
@@ -3,6 +3,57 @@ import { db } from '@/lib/db';
 import { annotations } from '@/lib/db/schema';
 import { eq } from 'drizzle-orm';
 
+export async function PATCH(
+  request: NextRequest,
+  { params }: { params: Promise<{ id: string }> }
+) {
+  try {
+    const { id: idParam } = await params;
+    const id = parseInt(idParam);
+
+    if (isNaN(id)) {
+      return NextResponse.json(
+        { error: 'Invalid annotation ID' },
+        { status: 400 }
+      );
+    }
+
+    const body = await request.json();
+    const { geometry } = body;
+
+    if (!geometry) {
+      return NextResponse.json(
+        { error: 'Geometry data is required' },
+        { status: 400 }
+      );
+    }
+
+    const result = await db
+      .update(annotations)
+      .set({ geometry: JSON.stringify(geometry) })
+      .where(eq(annotations.id, id))
+      .returning();
+
+    if (result.length === 0) {
+      return NextResponse.json(
+        { error: 'Annotation not found' },
+        { status: 404 }
+      );
+    }
+
+    const updated = result[0];
+    return NextResponse.json({
+      ...updated,
+      geometry: updated.geometry ? JSON.parse(updated.geometry as string) : null,
+    });
+  } catch (error: any) {
+    return NextResponse.json(
+      { error: error.message || 'Failed to update annotation' },
+      { status: 500 }
+    );
+  }
+}
+
 export async function DELETE(
   request: NextRequest,
   { params }: { params: Promise<{ id: string }> }
diff --git a/src/components/SvgOverlay.tsx b/src/components/SvgOverlay.tsx
index 9d56c93..2c14698 100644
--- a/src/components/SvgOverlay.tsx
+++ b/src/components/SvgOverlay.tsx
@@ -30,6 +30,12 @@ interface Point {
   price: number;
 }
 
+interface DragState {
+  lineId: number;
+  endpoint: 'start' | 'end';
+  originalPoint: Point;
+}
+
 export default function SvgOverlay({
   chart,
   series,
@@ -43,6 +49,7 @@ export default function SvgOverlay({
   const [drawingLine, setDrawingLine] = useState<{ start: Point; current: Point } | null>(null);
   const [mousePosition, setMousePosition] = useState<{ x: number; y: number } | null>(null);
   const [selectedLineId, setSelectedLineId] = useState<number | null>(null);
+  const [dragState, setDragState] = useState<DragState | null>(null);
 
   // Fetch annotations
   const fetchAnnotations = async () => {
@@ -137,12 +144,35 @@ export default function SvgOverlay({
 
     setMousePosition({ x, y });
 
+    // Handle line drawing
     if (drawingLine && activeTool === 'line') {
       const dataPoint = pixelToData(x, y);
       if (dataPoint) {
         setDrawingLine((prev) => (prev ? { ...prev, current: dataPoint } : null));
       }
     }
+
+    // Handle endpoint dragging
+    if (dragState && mousePosition) {
+      const dataPoint = pixelToData(x, y);
+      if (dataPoint) {
+        // Update annotations array optimistically for preview
+        setAnnotations((prev) =>
+          prev.map((ann) => {
+            if (ann.id === dragState.lineId && ann.geometry) {
+              const updatedGeometry = {
+                ...ann.geometry,
+                ...(dragState.endpoint === 'start'
+                  ? { startTime: dataPoint.time, startPrice: dataPoint.price }
+                  : { endTime: dataPoint.time, endPrice: dataPoint.price }),
+              };
+              return { ...ann, geometry: updatedGeometry };
+            }
+            return ann;
+          })
+        );
+      }
+    }
   };
 
   // Handle click
@@ -394,6 +424,92 @@ export default function SvgOverlay({
     );
   };
 
+  // Handle mouse down on endpoint handle
+  const handleHandleMouseDown = (e: React.MouseEvent, lineId: number, endpoint: 'start' | 'end') => {
+    e.stopPropagation(); // Prevent line click
+    const line = annotations.find((a) => a.id === lineId);
+    if (!line?.geometry) return;
+
+    const point = endpoint === 'start'
+      ? { time: line.geometry.startTime!, price: line.geometry.startPrice! }
+      : { time: line.geometry.endTime!, price: line.geometry.endPrice! };
+
+    setDragState({ lineId, endpoint, originalPoint: point });
+  };
+
+  // Handle mouse up - save dragged endpoint
+  const handleMouseUp = async () => {
+    if (!dragState || !mousePosition) return;
+
+    const dataPoint = pixelToData(mousePosition.x, mousePosition.y);
+    if (!dataPoint) return;
+
+    const line = annotations.find((a) => a.id === dragState.lineId);
+    if (!line?.geometry) return;
+
+    const updatedGeometry = {
+      ...line.geometry,
+      ...(dragState.endpoint === 'start'
+        ? { startTime: dataPoint.time, startPrice: dataPoint.price }
+        : { endTime: dataPoint.time, endPrice: dataPoint.price }),
+    };
+
+    try {
+      const response = await fetch(`/api/annotations/${dragState.lineId}`, {
+        method: 'PATCH',
+        headers: { 'Content-Type': 'application/json' },
+        body: JSON.stringify({ geometry: updatedGeometry }),
+      });
+
+      if (response.ok) {
+        await fetchAnnotations();
+        onAnnotationChange?.();
+      }
+    } catch (error) {
+      console.error('Failed to update annotation:', error);
+    }
+
+    setDragState(null);
+  };
+
+  // Render endpoint handles for selected line
+  const renderHandles = () => {
+    if (!selectedLineId) return null;
+
+    const line = annotations.find((a) => a.id === selectedLineId);
+    if (!line || !line.geometry) return null;
+
+    const start = dataToPixel(line.geometry.startTime!, line.geometry.startPrice!);
+    const end = dataToPixel(line.geometry.endTime!, line.geometry.endPrice!);
+
+    if (!start || !end) return null;
+
+    return (
+      <>
+        <circle
+          cx={start.x}
+          cy={start.y}
+          r={6}
+          fill="white"
+          stroke={line.color || '#3b82f6'}
+          strokeWidth={2}
+          style={{ cursor: 'move' }}
+          onMouseDown={(e) => handleHandleMouseDown(e, line.id, 'start')}
+        />
+        <circle
+          cx={end.x}
+          cy={end.y}
+          r={6}
+          fill="white"
+          stroke={line.color || '#3b82f6'}
+          strokeWidth={2}
+          style={{ cursor: 'move' }}
+          onMouseDown={(e) => handleHandleMouseDown(e, line.id, 'end')}
+        />
+      </>
+    );
+  };
+
   if (!chart || !series) return null;
 
   return (
@@ -411,10 +527,12 @@ export default function SvgOverlay({
       }}
       onMouseMove={handleMouseMove}
       onClick={handleClick}
+      onMouseUp={handleMouseUp}
     >
       {renderLines()}
       {renderPreviewLine()}
       {renderCursorCircle()}
+      {renderHandles()}
     </svg>
   );
 }