diff --git a/package-lock.json b/package-lock.json
index 48ff0a6..3a7de3f 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -15,7 +15,7 @@
         "@types/leaflet": "^1.9.21",
         "comlink": "^4.4.2",
         "geolib": "^3.3.4",
-        "gtfs-sqljs": "github:sysdevrun/gtfs-sqljs#7912bef",
+        "gtfs-sqljs": "github:sysdevrun/gtfs-sqljs#005bf84",
         "leaflet": "^1.9.4",
         "react": "^18.3.1",
         "react-dom": "^18.3.1",
@@ -3412,7 +3412,7 @@
     },
     "node_modules/gtfs-sqljs": {
       "version": "0.3.0",
-      "resolved": "git+ssh://git@github.com/sysdevrun/gtfs-sqljs.git#7912bef5dc0dc3c16cb2aa4ca19c6f03e2bcd015",
+      "resolved": "git+ssh://git@github.com/sysdevrun/gtfs-sqljs.git#005bf84de587b0730c26385fd9fb9b9273189526",
       "license": "MIT",
       "dependencies": {
         "jszip": "^3.10.1",
diff --git a/package.json b/package.json
index ffa414e..431c8c3 100644
--- a/package.json
+++ b/package.json
@@ -17,7 +17,7 @@
     "@types/leaflet": "^1.9.21",
     "comlink": "^4.4.2",
     "geolib": "^3.3.4",
-    "gtfs-sqljs": "github:sysdevrun/gtfs-sqljs#7912bef",
+    "gtfs-sqljs": "github:sysdevrun/gtfs-sqljs#005bf84",
     "leaflet": "^1.9.4",
     "react": "^18.3.1",
     "react-dom": "^18.3.1",
diff --git a/src/App.tsx b/src/App.tsx
index ebc915d..1c9c82e 100644
--- a/src/App.tsx
+++ b/src/App.tsx
@@ -160,6 +160,8 @@ function App() {
   const [loadingProgress, setLoadingProgress] = useState<ProgressInfo | null>(null)
   const [error, setError] = useState<string | null>(null)
   const [realtimeLastUpdated, setRealtimeLastUpdated] = useState<number>(0)
+  const [lastRtFetchTimestamp, setLastRtFetchTimestamp] = useState<number | null>(null)
+  const [secondsSinceLastUpdate, setSecondsSinceLastUpdate] = useState<number | null>(null)
 
   // Web Worker reference
   const workerRef = useRef<Remote<GtfsWorkerAPI> | null>(null)
@@ -341,6 +343,10 @@ function App() {
       setVehicles(sortedVehicles)
       setTripUpdates(tripUpdatesData)
 
+      // Get and store the last realtime fetch timestamp from the library
+      const rtTimestamp = await workerRef.current.getLastRealtimeFetchTimestamp()
+      setLastRtFetchTimestamp(rtTimestamp)
+
       // Update timestamp to trigger stop times refresh
       setRealtimeLastUpdated(Date.now())
     } catch (err) {
@@ -370,6 +376,25 @@ function App() {
     return () => clearInterval(interval)
   }, [gtfsLoaded, config.updateInterval, updateRealtimeData])
 
+  // Update seconds since last realtime update every second
+  useEffect(() => {
+    if (lastRtFetchTimestamp === null) {
+      setSecondsSinceLastUpdate(null)
+      return
+    }
+
+    const updateSeconds = () => {
+      const now = Date.now()
+      const seconds = Math.floor((now - lastRtFetchTimestamp) / 1000)
+      setSecondsSinceLastUpdate(seconds)
+    }
+
+    updateSeconds()
+    const interval = setInterval(updateSeconds, 1000)
+
+    return () => clearInterval(interval)
+  }, [lastRtFetchTimestamp])
+
   // Load trips for selected route (Browse Data tab)
   useEffect(() => {
     if (!workerRef.current || !gtfsLoaded || !selectedRoute || !gtfsApiRef.current) return
@@ -454,7 +479,9 @@ function App() {
                 {agencies.length > 0 && `${agencies.map(a => a.agency_name).join(', ')} - `}GTFS Real-Time Explorer
               </Typography>
               <Typography variant="caption" sx={{ opacity: 0.9 }}>
-                Explore transit data with gtfs-sqljs
+                {secondsSinceLastUpdate !== null
+                  ? `GTFS-RT: last update ${secondsSinceLastUpdate} seconds ago`
+                  : 'Explore transit data with gtfs-sqljs'}
               </Typography>
             </Box>
           </Toolbar>
diff --git a/src/gtfs.worker.ts b/src/gtfs.worker.ts
index e222fa8..f607b08 100644
--- a/src/gtfs.worker.ts
+++ b/src/gtfs.worker.ts
@@ -67,6 +67,7 @@ export interface GtfsWorkerAPI {
   // Realtime methods
   fetchRealtimeData: () => Promise<void>
   getActiveServiceIds: (date: string) => string[]
+  getLastRealtimeFetchTimestamp: () => number | null
 
   // Database methods
   getDatabase: () => Uint8Array | null
@@ -223,6 +224,13 @@ class GtfsWorker implements GtfsWorkerAPI {
     await this.gtfs.fetchRealtimeData()
   }
 
+  getLastRealtimeFetchTimestamp(): number | null {
+    if (!this.gtfs) {
+      return null
+    }
+    return this.gtfs.getLastRealtimeFetchTimestamp()
+  }
+
   getDatabase(): Uint8Array | null {
     if (!this.gtfs) {
       return null