Duplicate Detection

Detect and reject duplicate files by computing CRC32 hashes in the browser. Prevent users from uploading the same file twice.

What you should see: add the same file twice and the second copy is refused. Detection is by content, so a renamed copy is still caught.

Drag & drop files here, or paste from clipboard

Try selecting the same file twice - the duplicate will be rejected automatically.

<core-upload asp-upload-url="/api/upload/upload"
 asp-detect-duplicates="true"
 asp-multiple="true"
 asp-progress="true">
</core-upload>