What metadata is shown?

Name, browser-reported MIME type, exact byte size, human-readable size, last-modified timestamp, and pixel dimensions for images.

Is the file uploaded?

No. The browser reads File.name, File.type, File.size, and File.lastModified locally — image dimensions come from briefly loading the file into an Image element in-memory.

Does it read EXIF data?

Not in this tool. Only basic file metadata exposed by the File API is shown. Use a dedicated EXIF viewer for camera metadata.

Why is the MIME type sometimes blank or generic?

Browsers guess MIME from the extension. Unknown extensions yield an empty type or application/octet-stream.

name · mime · size · modified · dimensions

Inspect any file's metadata

Drop files in to see name, browser-reported MIME, byte size, last-modified date, and image pixel dimensions. Runs entirely in your browser.

File Metadata Viewer

Add files

Files

inspected

Total size

0 B

combined

Images

with dims

Status

—

drop files

input · drop files

Click or drop one or more files

Image files (PNG/JPG/etc.) report pixel dimensions in addition to the basic stats.

output · metadata (0)

No files yet

Quick Start

How to inspect file metadata

The browser File API exposes a tiny set of attributes for any file you drop in — no upload required.

01
Drop files
One file or a whole folder selection.
Inputs are treated as UTF-8 throughout the pipeline and validated client-side as you type — nothing dispatches until the value is well-formed.
inpututf-8client-sidevalidated
files · textn · set
```
drop or click
```
loaded · parsedclient-side
02
Read MIME and size
Type and bytes come straight from the File object.
Each toggle re-computes through a memoised hook, so flipping options never resets your input and the UI stays snappy on large inputs.
basicsoptionslivememoisedtoggles
mime · memoisedtype · live
```
image/png · 320 KB
```
options set · memoisedlive
03
Image dimensions
Pictures decode in-memory to grab naturalWidth/Height.
Randomness — where used — comes from crypto.getRandomValues, never Math.random. Heavy work sits in useMemo.
imagecomputeinstantlocaldeterministic
dims · instantpx · computed
```
1024 × 768
```
computed · instantinstant
04
Stack many files
Add more — each is prepended to the list with full info.
Copy writes through navigator.clipboard and downloads use a Blob — zero network traffic. Same input plus same options always yield the same bytes.
bulkcopydownloadzero-networkreproducible
ok · copiedready · copied
```
inspected
```
shipped · ready to shipsuccess

Pro tips

Pro tips for everyday utilities

Reach for crypto.getRandomValues

Cryptographically random for IDs, tokens, salts. Math.random is for animation and games, not security.

Sort IDs lexicographically

UUID v4 has no time ordering. Use ULID or UUID v7 if you need sorted IDs.

Mock data with seeds

Faker-style libraries can be seeded so tests are reproducible. Embed the seed in the fixture file.

Reference cards beat memory

Cheatsheets for Vim, Git, Docker, Linux signals are faster than man pages when you’re mid-flow.

Browser APIs vary

Touch events, gamepads, and clipboard differ across vendors. Feature-detect before use.

Persist in the right place

localStorage for user preferences, sessionStorage for transient state, IndexedDB for structured data.

Use Cases

When to inspect metadata

Triage uploads, audit batches, sanity-check exports.

Upload debugging

See exactly what MIME the browser is sending. Random values come from crypto.getRandomValues — cryptographically secure for tokens, salts, and session IDs. Math.random is deterministic enough for animations but predictable enough to be a security bug.

CSPRNG-backed

Asset audits

Spot oversized images before they hit CI. Pair with hashids, ULID, or UUID v7 when you need both random and sortable — useful for primary keys, public-facing IDs, and event log ordering without a sequence column.

reproducible

Quick triage

Read filename, size, and date without opening files. Output is deterministic given the same seed, so fixtures and tests stay reproducible across CI runs and contributor machines. Embed the seed in the fixture file for full replay.

snappy

QA

Verify an export matches expected dimensions. Heavy work runs through useMemo so the UI stays snappy on large inputs. Same input + same options yields identical bytes — the kind of stability snapshot tests rely on.

feature-detected

Capture review

See modified-time stamps to order files. Storage tools persist to the right backend: localStorage for user preferences, sessionStorage for transient state, IndexedDB for structured data. Pick the right shelf and quota worries disappear.

deterministic

Doc inventory

Inspect a dropped batch from a folder. Browser feature detection: clipboard, fullscreen, gamepad, and Web Bluetooth APIs gracefully fall back when unavailable. No surprise white screens on Safari or older Firefox.

production-ready

FAQ

Frequently asked questions

Why is the MIME sometimes empty?

Browsers sniff a small set of types. Unknown extensions yield an empty string — we fall back to —.

Where does the date come from?

file.lastModified is the OS modified-time at selection time.

Does it read EXIF/ID3 tags?

No — this tool covers the basics. Use the EXIF Viewer for image camera data.

What about very large files?

Metadata reads are cheap; image decode for dimensions may take a moment on huge raws.

Is anything sent to a server?

No. Everything runs locally in your browser.

Suggest a tool

Something missing?

Tell us what you need. We ship the top requests every two weeks.

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