diff --git a/lib/clouddrop-upload.js b/lib/clouddrop-upload.js
index 76e7ff9..25a08de 100644
--- a/lib/clouddrop-upload.js
+++ b/lib/clouddrop-upload.js
@@ -159,7 +159,7 @@ class ClouddropUploader {
     // Reuse a single buffer for all chunks (only the last chunk may be smaller,
     // in which case we slice a view). Avoids 64× 16 MB allocations on a 1 GB
     // file — real GC pressure during busy uploads.
-    const fd = fs.openSync(filePath, 'r');
+    const fh = await fs.promises.open(filePath, 'r');
     let bytesSent = 0;
     const reusableBuf = Buffer.allocUnsafe(chunkSize);
     try {
@@ -169,7 +169,7 @@ class ClouddropUploader {
         const offset = i * chunkSize;
         const remaining = fileSize - offset;
         const thisChunkSize = Math.min(chunkSize, remaining);
-        fs.readSync(fd, reusableBuf, 0, thisChunkSize, offset);
+        await fh.read(reusableBuf, 0, thisChunkSize, offset);
         const body = thisChunkSize === chunkSize
           ? reusableBuf
           : reusableBuf.subarray(0, thisChunkSize);
@@ -194,7 +194,7 @@ class ClouddropUploader {
         if (progressCb) progressCb(bytesSent, fileSize);
       }
     } finally {
-      try { fs.closeSync(fd); } catch {}
+      try { await fh.close(); } catch {}
     }
 
     // 3. Complete session — all bytes are already on the server at this point.