Max File Size Validation

Limit the maximum file size using the asp-max-size attribute. Supports human-readable values like "2MB", "500KB", or "1GB". Files exceeding the limit are rejected before upload.

What you should see: anything over 2 MB is refused the moment it is selected — no request is made and no time is wasted uploading a file the server would reject.

Max 2 MB

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Max 500 KB

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<core-upload asp-upload-url="/api/upload/upload"
 asp-max-size="2MB"
 asp-progress="true"
 asp-button-text="Select File (max 2MB)">
</core-upload>

<core-upload asp-upload-url="/api/upload/upload"
 asp-max-size="500KB"
 asp-button-text="Select File (max 500KB)">
</core-upload>