DocForensic

PDF Tag Inspector

Browse a tagged PDF's accessibility tag structure as a tree, see each tag's approximate location on the page, and fix problems - retag, re-parent, or add a missing tag - directly.

This tool walks a tagged PDF's underlying structure tree into a browsable, collapsible tree - Document, Section, Heading, Paragraph, Figure, Table, and so on - and matches each tag to its approximate location on the page so you can see (and click between) the tag and the content it represents. Problems are flagged directly in the tree: a figure with no alt text, a heading level that skips (H1 straight to H3), a table missing header cells, or a tag that exists but isn't actually reachable from the document's logical structure.

Positions shown on the page are approximate - matched by tag type and position, not an exact per-tag lookup into the page's content stream - always treat them as a guide for navigating the tree, not pixel-exact geometry. You can retag an element, drag it to a different parent, or add a new tag for content that has none at all, then save a corrected copy.

Simple workflow

How it works

  1. 1

    Add tagged PDFs

    Add one or more already-tagged PDFs to the list.

  2. 2

    Scan

    Run the scan to see the full tag tree, flagged issues, and each tag's approximate page position.

  3. 3

    Edit & save

    Retag, re-parent, or add tags as needed, then save the corrected structure and download it.

Frequently asked questions

My PDF has no tags at all - can I still use this tool?

Yes, with an explicit step: the tool will offer to create a minimal starting structure (a single Document root) rather than doing it automatically, since a completely untagged document has nothing for this tool to inspect otherwise.

Are the highlighted positions on the page exact?

No - they're matched by tag type and position on the page, not an exact per-tag lookup into the PDF's content stream. Reliable enough to see roughly where a tag is and jump between the tree and the page, but treat it as a guide rather than pixel-perfect geometry.

What does "orphaned tag" mean?

A struct element that physically exists in the PDF but isn't reachable from the document's logical structure root - it was tagged at some point but excluded from the reading order. It's shown separately in the tree so you can see it, but it can't be re-parented directly; retag or replace it instead.

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