diff --git a/src/main.rs b/src/main.rs
index edfd611..a1d66ac 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -66,6 +66,8 @@ async fn main() -> std::io::Result<()> {
         .max_size(100_000)
         .to_owned();
     crate::flow_debug!("video cache initialized max_size=100000");
+    cache.spawn_hourly_cleanup();
+    crate::flow_debug!("video cache hourly cleanup task spawned");
     let _ = providers::configure_runtime_validation(pool.clone(), cache.clone(), requester.clone());
 
     thread::spawn(move || {
diff --git a/src/util/cache.rs b/src/util/cache.rs
index 28a9b52..dd69c7c 100644
--- a/src/util/cache.rs
+++ b/src/util/cache.rs
@@ -5,6 +5,11 @@ use std::time::Duration;
 
 use crate::videos::VideoItem;
 
+/// Entries older than this are considered stale and dropped.
+const ENTRY_TTL: Duration = Duration::from_secs(60 * 60);
+/// How often the background task scans the cache for stale entries.
+const CLEANUP_INTERVAL: Duration = Duration::from_secs(60 * 60);
+
 #[derive(Clone)]
 pub struct VideoCache {
     cache: Arc<Mutex<std::collections::HashMap<String, (SystemTime, Vec<VideoItem>)>>>, // url -> time+Items
@@ -55,25 +60,59 @@ impl VideoCache {
         None
     }
 
+    /// Number of entries currently held.
+    pub fn len(&self) -> usize {
+        self.cache.lock().map(|c| c.len()).unwrap_or(0)
+    }
+
+    /// Drop every entry older than [`ENTRY_TTL`]. Returns how many were removed.
+    pub fn prune_expired(&self) -> usize {
+        let mut removed = 0;
+        if let Ok(mut cache) = self.cache.lock() {
+            cache.retain(|_key, (time, _items)| match time.elapsed() {
+                // Keep entries within the TTL; drop the rest.
+                Ok(elapsed) => {
+                    let keep = elapsed <= ENTRY_TTL;
+                    if !keep {
+                        removed += 1;
+                    }
+                    keep
+                }
+                // Clock went backwards: keep the entry rather than guessing.
+                Err(_) => true,
+            });
+        }
+        removed
+    }
+
+    /// Spawn a background task that prunes stale entries once per hour for the
+    /// lifetime of the process.
+    pub fn spawn_hourly_cleanup(&self) {
+        let cache = self.clone();
+        tokio::spawn(async move {
+            let mut interval = tokio::time::interval(CLEANUP_INTERVAL);
+            // The first tick fires immediately; consume it so the cache isn't
+            // scanned the instant the server starts.
+            interval.tick().await;
+            loop {
+                interval.tick().await;
+                let removed = cache.prune_expired();
+                let remaining = cache.len();
+                // Referenced unconditionally so the bindings aren't flagged as
+                // unused when `flow_debug!` compiles to nothing (debug off).
+                let _ = (removed, remaining);
+                crate::flow_debug!(
+                    "video cache cleanup removed={} remaining={}",
+                    removed,
+                    remaining
+                );
+            }
+        });
+    }
+
     #[allow(dead_code)]
     pub async fn check(&self) -> Result<(), Box<dyn std::error::Error>> {
-        let iter = match self.entries() {
-            Some(iter) => iter,
-            None => {
-                return Err(Box::new(std::io::Error::new(
-                    std::io::ErrorKind::Other,
-                    "Could not get entries",
-                )));
-            }
-        };
-
-        for (key, (time, _items)) in iter {
-            if let Ok(elapsed) = time.elapsed() {
-                if elapsed > Duration::from_secs(60 * 60) {
-                    self.remove(&key);
-                }
-            }
-        }
+        self.prune_expired();
         Ok(())
     }
 }