About PDF inspector
A PDF is not a page format so much as a small database that happens to describe pages. It contains numbered objects — dictionaries, arrays, names, numbers and byte streams — wired together by indirect references, with a cross-reference index telling a reader where each object starts and a trailer pointing at the document catalogue. Almost every practical PDF question is really a question about those objects: which font objects carry embedded programs, how many pixels the image XObjects actually hold, whether the encrypt dictionary is present, where the megabytes went. This inspector parses that structure on your device and reports it in one pass, so instead of guessing at a file you can read it. It is deliberately a survey rather than a verdict: it tells you what the document contains and leaves the judgement to you, because what counts as a problem depends entirely on whether the file is heading to a press, an archive, an email thread or a build pipeline.
How to PDF inspector
- 01
Open the PDF
Drop a file onto the drop zone. It is parsed in the tab; no request carries the bytes anywhere.
- 02
Choose your depth
Leave Verbose off for the summarised report. Turn it on when you need per-object and per-page detail for a specific investigation.
- 03
Read the report
Sections cover document, pages, fonts, images, colour, security, interactivity, metadata, structure and size. Each one stands alone.
- 04
Export or move on
Copy the report as JSON for a ticket or a build log, or jump to the specialised tool for whichever section raised a question.
What this tool does
- PDF header version and the catalogue /Version entry, reported separately because they can disagree
- Page count plus page dimensions grouped by size, so a stray Letter page in an A4 document is immediately visible
- Font inventory: name, subtype, embedded or referenced, subset or full, encoding
- Image inventory: object count, stored pixel dimensions, colour space, compression filter and effective DPI at placed size
- Security: encryption presence, algorithm and key length, plus the permission bits actually set
- Interactivity: annotation counts by subtype, bookmark tree depth, embedded attachments, AcroForm field count
- Metadata: document information dictionary and XMP packet, shown side by side
- Structure: total object count, xref type, linearisation flag, incremental update generations, stream filters in use
- Byte-level size breakdown attributing file weight to images, fonts, content streams, metadata and structural overhead
Limitations worth knowing
Every PDF tool has constraints. Stating them plainly is more useful than discovering them halfway through your work.
- This is a report, not a validator. It describes what the document contains and does not certify conformance to any standard.
- Encrypted PDFs need their password before the objects can be parsed; owner-password-only files are usually readable without it.
- Damaged or non-conforming files may parse partially. The report says which sections could not be read rather than inventing values.
- Effective DPI figures assume the image is placed once. An image reused at several sizes on different pages reports a range, not a single number.
- Byte attribution is derived from stream lengths and object sizes, so the section totals are close to but not exactly the file size — the difference is the xref index and trailer.
How your file is handled
This tool runs entirely inside this browser tab. When you choose a file, your browser reads it from your own disk and hands the bytes to JavaScript running on this page — no network request carries your document anywhere. You can confirm that yourself: open your browser’s developer tools, switch to the Network panel, and run the tool. You will see no upload.
Nothing is stored after the fact. Closing or reloading this tab discards the file, the result and everything derived from them, because none of it ever left your machine. Read how local processing works.
Questions about PDF inspector
What does this tell me that opening the PDF in a viewer does not?
A viewer shows you the rendered result. This shows you the machinery that produced it: which fonts are embedded rather than assumed to exist, how many pixels an image really holds versus how large it is drawn, whether the file carries an encryption dictionary, how many objects are in it and where the bytes live. None of that is visible on the rendered page.
Is my PDF uploaded?
No. Parsing happens in your browser tab with a local library. You can keep the network inspector open while you run it and watch no request carrying file content leave.
Where should I start reading the report?
Start with whichever problem sent you here. Rendering differences on another machine mean the fonts section; an oversized file means the size breakdown; a printing surprise means the page-size section; a press rejection means the colour section.
Why do the header version and the catalogue version differ in my file?
Because they are written at different times by different software. The header is stamped when the file is first produced; an editor that adds a feature requiring a newer version may write a catalogue /Version entry instead of rewriting the header. Readers prefer the catalogue value when both exist.
The report says a font is embedded and subset. Is that a problem?
No, that is the normal and desirable case. Subsetting stores only the glyphs the document actually uses, which is why a document using three weights of a large family does not carry three full fonts. It becomes a problem only if someone later needs to edit the text and types a character the subset does not include.
Can I use this output in a build or review pipeline?
Yes — copy the JSON report. People commonly use it as a pre-flight check before publishing: assert that fonts are embedded, that no page strays from the expected size, and that the file is not encrypted.
Tools that pair with this one
- PDF Structure InspectorSee how the document is wired together, from trailer to page tree.
- PDF Font InspectorFind out which fonts travel with your PDF and which depend on the reader having them.
- PDF Size AnalyzerA byte-level breakdown of where your PDF weight actually is.
- PDF Page Size DetectorMeasure every page box in a PDF and catch the mixed sizes that ruin a print run.
- PDF Metadata ViewerRead the fields a PDF carries about itself, including the raw XMP.
- Compress PDFMake a PDF smaller by re-encoding its images and cleaning up its internals.