diff --git a/build.rs b/build.rs
index 01afed645..2320503bb 100644
--- a/build.rs
+++ b/build.rs
@@ -1,22 +1,30 @@
+use std::fs;
 use std::path::Path;
 use std::process::Command;
+use std::time::SystemTime;
 
 fn main() {
     let dist_dir = Path::new("web/dist");
     let web_dir = Path::new("web");
 
-    // Tell Cargo to re-run this script when web source files change.
+    // Tell Cargo to re-run this script when web sources or bundled assets change.
     println!("cargo:rerun-if-changed=web/src");
+    println!("cargo:rerun-if-changed=web/public");
     println!("cargo:rerun-if-changed=web/index.html");
     println!("cargo:rerun-if-changed=web/package.json");
+    println!("cargo:rerun-if-changed=web/package-lock.json");
+    println!("cargo:rerun-if-changed=web/tsconfig.json");
+    println!("cargo:rerun-if-changed=web/tsconfig.app.json");
+    println!("cargo:rerun-if-changed=web/tsconfig.node.json");
     println!("cargo:rerun-if-changed=web/vite.config.ts");
+    println!("cargo:rerun-if-changed=web/dist");
 
     // Attempt to build the web frontend if npm is available and web/dist is
     // missing or stale.  The build is best-effort: when Node.js is not
     // installed (e.g. CI containers, cross-compilation, minimal dev setups)
     // we fall back to the existing stub/empty dist directory so the Rust
     // build still succeeds.
-    let needs_build = !dist_dir.join("index.html").exists();
+    let needs_build = web_build_required(web_dir, dist_dir);
 
     if needs_build && web_dir.join("package.json").exists() {
         if let Ok(npm) = which_npm() {
@@ -77,6 +85,49 @@ fn main() {
     ensure_dist_dir(dist_dir);
 }
 
+fn web_build_required(web_dir: &Path, dist_dir: &Path) -> bool {
+    let Some(dist_mtime) = latest_modified(dist_dir) else {
+        return true;
+    };
+
+    [
+        web_dir.join("src"),
+        web_dir.join("public"),
+        web_dir.join("index.html"),
+        web_dir.join("package.json"),
+        web_dir.join("package-lock.json"),
+        web_dir.join("tsconfig.json"),
+        web_dir.join("tsconfig.app.json"),
+        web_dir.join("tsconfig.node.json"),
+        web_dir.join("vite.config.ts"),
+    ]
+    .into_iter()
+    .filter_map(|path| latest_modified(&path))
+    .any(|mtime| mtime > dist_mtime)
+}
+
+fn latest_modified(path: &Path) -> Option<SystemTime> {
+    let metadata = fs::metadata(path).ok()?;
+    if metadata.is_file() {
+        return metadata.modified().ok();
+    }
+    if !metadata.is_dir() {
+        return None;
+    }
+
+    let mut latest = metadata.modified().ok();
+    let entries = fs::read_dir(path).ok()?;
+    for entry in entries.flatten() {
+        if let Some(child_mtime) = latest_modified(&entry.path()) {
+            latest = Some(match latest {
+                Some(current) if current >= child_mtime => current,
+                _ => child_mtime,
+            });
+        }
+    }
+    latest
+}
+
 /// Ensure the dist directory exists so `rust-embed` does not fail at compile
 /// time even when the web frontend is not built.
 fn ensure_dist_dir(dist_dir: &Path) {