diff --git a/package.json b/package.json
index 652f4cc..83f5616 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@drop-oss/droplet",
-  "version": "3.4.0",
+  "version": "3.5.0",
   "main": "index.js",
   "types": "index.d.ts",
   "napi": {
diff --git a/src/version/backends.rs b/src/version/backends.rs
index 12e1983..cdf78ce 100644
--- a/src/version/backends.rs
+++ b/src/version/backends.rs
@@ -111,6 +111,17 @@ impl VersionBackend for PathVersionBackend {
 
 pub static SEVEN_ZIP_INSTALLED: LazyLock<bool> =
   LazyLock::new(|| Command::new("7z").output().is_ok());
+// https://7-zip.opensource.jp/chm/general/formats.htm
+// Intentionally repeated some because it's a trivial cost and it's easier to directly copy from the docs above
+pub const SUPPORTED_FILE_EXTENSIONS: [&str; 89] = [
+  "7z", "bz2", "bzip2", "tbz2", "tbz", "gz", "gzip", "tgz", "tar", "wim", "swm", "esd", "xz",
+  "txz", "zip", "zipx", "jar", "xpi", "odt", "ods", "docx", "xlsx", "epub", "apm", "ar", "a",
+  "deb", "lib", "arj", "cab", "chm", "chw", "chi", "chq", "msi", "msp", "doc", "xls", "ppt",
+  "cpio", "cramfs", "dmg", "ext", "ext2", "ext3", "ext4", "img", "fat", "img", "hfs", "hfsx",
+  "hxs", "hxr", "hxq", "hxw", "lit", "ihex", "iso", "img", "lzh", "lha", "lzma", "mbr", "mslz",
+  "mub", "nsis", "ntfs", "img", "mbr", "rar", "r00", "rpm", "ppmd", "qcow", "qcow2", "qcow2c",
+  "squashfs", "udf", "iso", "img", "scap", "uefif", "vdi", "vhd", "vmdk", "xar", "pkg", "z", "taz",
+];
 
 #[derive(Clone)]
 pub struct ZipVersionBackend {
@@ -189,7 +200,12 @@ impl VersionBackend for ZipVersionBackend {
         continue;
       }
       results.push(VersionFile {
-        relative_filename: name.into_iter().map(|v| *v).fold(String::new(), |a, b| a + b + " ").trim_end().to_owned(),
+        relative_filename: name
+          .into_iter()
+          .map(|v| *v)
+          .fold(String::new(), |a, b| a + b + " ")
+          .trim_end()
+          .to_owned(),
         permission: 0o744, // owner r/w/x, everyone else, read
         size: size.parse().unwrap(),
       });
diff --git a/src/version/utils.rs b/src/version/utils.rs
index 7288465..40c2073 100644
--- a/src/version/utils.rs
+++ b/src/version/utils.rs
@@ -10,7 +10,9 @@ use napi::{bindgen_prelude::*, sys::napi_value__, tokio_stream::StreamExt};
 use tokio_util::codec::{BytesCodec, FramedRead};
 
 use crate::version::{
-  backends::{PathVersionBackend, ZipVersionBackend, SEVEN_ZIP_INSTALLED},
+  backends::{
+    PathVersionBackend, ZipVersionBackend, SEVEN_ZIP_INSTALLED, SUPPORTED_FILE_EXTENSIONS,
+  },
   types::{ReadToAsyncRead, VersionBackend, VersionFile},
 };
 
@@ -33,6 +35,8 @@ pub fn create_backend_constructor<'a>(
   };
 
   if *SEVEN_ZIP_INSTALLED {
+    /*
+    Slow 7zip integrity test
     let mut test = Command::new("7z");
     test.args(vec!["t", path.to_str().expect("invalid utf path")]);
     let status = test.status().ok()?;
@@ -40,6 +44,18 @@ pub fn create_backend_constructor<'a>(
       let buf = path.to_path_buf();
       return Some(Box::new(move || Ok(Box::new(ZipVersionBackend::new(buf)?))));
     }
+     */
+    // Fast filename-based test
+    if let Some(extension) = path.extension().and_then(|v| v.to_str()) {
+      let supported = SUPPORTED_FILE_EXTENSIONS
+        .iter()
+        .find(|v| ***v == *extension)
+        .is_some();
+      if supported {
+        let buf = path.to_path_buf();
+        return Some(Box::new(move || Ok(Box::new(ZipVersionBackend::new(buf)?))));
+      }
+    }
   }
 
   None