diff --git a/backend/converter.py b/backend/converter.py
index c4e3eb4..070ba1d 100644
--- a/backend/converter.py
+++ b/backend/converter.py
@@ -77,6 +77,11 @@ def extract_if_needed(filename: str) -> Path:
     if not shutil.which(tool):
         raise RuntimeError(f"Extraction tool '{tool}' not found on host")
 
+    # Determine extraction base: use the file's parent directory
+    # (handles both tmp/in/ and tmp/{guid}/in/ paths)
+    extract_base = filepath.parent
+    extract_base.mkdir(parents=True, exist_ok=True)
+
     # Directory stem: strip extension(s)
     stem = name
     for e in sorted(tool_map, key=len, reverse=True):
@@ -85,7 +90,7 @@ def extract_if_needed(filename: str) -> Path:
             break
 
     # If already extracted, skip re-extraction
-    expected_dir = STAGING_IN / stem
+    expected_dir = extract_base / stem
     if expected_dir.is_dir() and any(
         f.suffix.lower() in DISK_EXTENSIONS
         for f in expected_dir.rglob("*")
@@ -94,12 +99,11 @@ def extract_if_needed(filename: str) -> Path:
         logger.info("Already extracted: %s", expected_dir)
         return expected_dir
 
-    # Snapshot STAGING_IN before extraction
-    before = set(STAGING_IN.iterdir()) if STAGING_IN.exists() else set()
+    # Snapshot before extraction
+    before = set(extract_base.iterdir()) if extract_base.exists() else set()
 
-    # Extract into STAGING_IN root (not a subdir) to avoid double nesting
-    # when the archive already has a top-level directory
-    result = subprocess.run(cmd, cwd=str(STAGING_IN), capture_output=True, text=True, timeout=600)
+    # Extract into the file's parent directory
+    result = subprocess.run(cmd, cwd=str(extract_base), capture_output=True, text=True, timeout=600)
     if result.returncode != 0:
         raise RuntimeError(f"{tool} failed: {result.stderr.strip()[:500]}")
 
@@ -108,12 +112,11 @@ def extract_if_needed(filename: str) -> Path:
     new_items = after - before
 
     # If the archive had a single top-level directory matching the stem, use it
-    expected_dir = STAGING_IN / stem
+    expected_dir = extract_base / stem
     if expected_dir in new_items and expected_dir.is_dir():
         result = expected_dir
     else:
-        # Collect scattered files into a subdirectory
-        out_dir = STAGING_IN / stem
+        out_dir = extract_base / stem
         out_dir.mkdir(parents=True, exist_ok=True)
         for item in new_items:
             shutil.move(str(item), str(out_dir / item.name))