File Type & Hex Inspector

Look beyond the filename. Inspect common file signatures and explore the underlying bytes without uploading or opening the file.

No uploads · No account · Read-only byte inspection

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BUILT FOR THE DETAILS

01Add your input
02Inspect type & bytes
03Export your report

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Inspect the file behind the name

Read locally · Bounded file slices

Choose a file or drag one here

Any file type · One file at a time · Read-only inspection

Reads small slices rather than loading the whole file. File contents are not uploaded, executed or rendered as documents.

Detection evidence

A signature is evidence, not proof of validity or safety. Container and text results may be ambiguous. This tool does not scan for malware.

Hex & ASCII view

Bytes per page

Hex offset | Hexadecimal bytes | Printable ASCII (other bytes shown as dots)

How to inspect a file type and its bytes

Choose one local file. The tool samples its header and checks known signatures, independently of the filename or browser-provided MIME type.
Read the evidence and extension comparison. A known signature can expose a renamed file; a generic container or text sample may not identify the exact subtype.
Browse hex pages or jump to a decimal offset such as 256, or a hexadecimal offset such as 0x100. Copy or download the visible range, or export the type report.

Supported signature families

Common images: PNG, JPEG, GIF, WebP, BMP, TIFF, BigTIFF, ICO, CUR, PSD, AVIF and HEIC/HEIF. Documents and archives: PDF, ZIP, GZIP, 7z, RAR, Bzip2, XZ, Zstandard, TAR, OLE compound files, SQLite and ISO 9660. Media: RIFF/WAVE/AVI, AIFF, FLAC, Ogg, ID3, MPEG audio, EBML and ISO-base-media families. Executables and fonts: ELF, MZ/PE, WebAssembly, WOFF, WOFF2, OpenType, TrueType and font collections.

ZIP-based Word, Excel, PowerPoint, EPUB, OpenDocument, Java and Android package hints use bounded container metadata. They do not validate the complete package or inspect macros. Conflicting subtype markers keep the generic ZIP result. WebM versus Matroska and some media codecs remain unresolved container families.

Text guesses and extension comparisons

Decodable text samples can suggest UTF-8/UTF-16 text, UTF-32 byte-order marks, JSON, XML, SVG, HTML, RTF or PEM. These are labeled as heuristics. Text extensions are reported as not conclusive. The browser-reported MIME is displayed separately because it may come from the filename or platform metadata.

Bounds and privacy

The header sample is at most 64 KiB. ZIP subtype inspection may additionally read the last 65,557 bytes and a central directory up to 256 KiB, with at most 4,096 entries. Large or unsupported ZIP directories remain generic. Each hex page contains 256 to 4,096 bytes. Size and offsets must fit JavaScript's safe-integer range and the browser must be able to read the local file.

The tool does not read the whole file for hashing, validate complete files, detect every possible format, identify all polyglots, verify authenticity or scan for malware. A deliberately forged or truncated file can contain a recognizable signature. The JSON report includes the filename, byte size, evidence and first 32 bytes in hex; the separate hex download contains only the displayed range. Clearing removes the file reference and revokes downloads. No browser storage is used.

Frequently asked questions

Does a PNG signature mean the file is a valid, safe PNG?

No. The signature identifies header evidence. Full decoding, structural validation and security scanning are outside this tool's scope.

Why does a DOCX or MP4 sometimes show a container family?

Many formats share containers. Some subtypes need internal metadata or complete parsing. This tool reports the evidence it can establish within its read bounds rather than assuming the subtype from the extension.

Can this inspect large files?

The tool reads bounded slices for detection and paging. It does not allocate a buffer for the complete file. Actual limits depend on the browser, local filesystem and safe integer offsets.

Can I edit or repair file bytes?

This viewer is read-only. It creates separate text/JSON reports and never rewrites the original file.

Continue your workflow

Inspect signature evidence, not file safety

Choose a file, inspect detected header evidence and page through the supported byte range. Save a report or displayed hex range when useful.

Scope of this workflow

The viewer is read-only. A recognizable signature does not establish structural validity or malware safety, and shared containers can obscure a specific subtype.

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