File Header Inspector
Read file header hex and detect likely file type for mismatched extensions, upload issues, and unknown files.
Read the first bytes of a file as Hex and detect the likely file type for mismatched extensions, unknown files, and upload issues.
Only the first 128 bytes are read in the browser. It helps identify common formats like PNG, JPG, PDF, ZIP, WebP, HEIC, MP3, and WAV.
Only the file header is read locally in your browser. The full file is not uploaded.
Select a file to see likely type, size, and header Hex here.
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Common use cases
- Inspect a file whose extension does not match its actual content and causes upload or open failures.
- Identify unknown, damaged, or extensionless attachments by checking their magic number and first bytes.
- Diagnose image, PDF, archive, audio, and video format issues before relying on the filename alone.