Add a Clickable Bookmark Outline to a PDF

Type one line per entry as a page number, a pipe and a title, and pdf-lib writes a real PDF outline into the document — the navigation sidebar readers already have, set to open automatically.

About the PDF Bookmark Creator

Long PDFs without an outline are miserable to use. Readers give you a scrollbar and a page count and nothing else, so finding section four of a two-hundred-page document means guessing, scrolling and guessing again. This tool adds the structure that should have been there, using nothing more than a list you type.

The format is deliberately plain: each line is a page number, a vertical bar, and the title you want shown. Lines that do not fit that pattern are skipped without complaint, and any entry pointing at a page the document does not have is dropped — if none of your page numbers exist, you get an error telling you how many pages there actually are. Titles are written as Unicode text, so umlauts, accents, and non-Latin scripts all survive intact rather than turning into question marks.

Key Features

  • One line per bookmark: Enter 12 | Chapter 2 and that is the whole syntax — no nesting characters, no indentation rules, no export format to learn.
  • A genuine PDF outline: The entries are written into the document catalogue as a proper Outlines structure with linked Prev and Next references, which is what makes them appear in the sidebar of every reader rather than as a page of links.
  • The sidebar opens on its own: The document is marked to open in outline mode, so a recipient sees the navigation immediately instead of having to know where the panel is hidden.
  • Unicode titles: Bookmark text is stored as hex-encoded Unicode, so German, French, Polish or Japanese chapter titles come through exactly as typed.
  • Bad lines fail quietly: Blank lines, notes to yourself and mistyped entries are ignored rather than breaking the run, so you can paste a rough list and refine it.
  • Nothing is transmitted: pdf-lib rewrites the document structure in your browser from code held on this domain, so a confidential draft gains its navigation without being sent for processing.

How to Use the PDF Bookmark Creator

  1. Add the PDF that needs an outline.
  2. In the box, type one line per bookmark in the form: page number, a vertical bar, then the title.
  3. Check the page numbers against the document — the entry jumps to the page you name, not to a heading it finds.
  4. Press Add Bookmarks and download the result, saved with -bookmarked appended.

How It Works

The tool builds the outline by hand at the object level: it allocates a reference for the outline root and one for each entry, gives every entry a title, a parent, a destination pointing at the page object, and Prev and Next links tying the entries into a chain, then registers the root in the document catalogue and sets the page mode so readers open with the panel visible.

Three limits follow from that construction. The outline is flat — every entry sits at the top level, so you cannot nest a section under a chapter. Destinations use the fit-page setting, meaning a click lands at the top of the page rather than scrolling to a heading partway down it. And adding bookmarks replaces any outline the document already had, rather than merging with it, so if the file arrived with a partial outline you should include those entries in your list as well.

When You Need It

A technical standards committee circulates a draft specification running to several hundred clauses for comment. Members who cannot navigate it will not read it properly, and the draft is confidential to the committee until publication — putting it through an online PDF service to add navigation would circulate it exactly as far as the embargo says it must not go. A typed list of clause headings and page numbers fixes it in a couple of minutes.

A manufacturer ships a three-hundred-page service manual alongside its equipment. An engineer standing at a machine with a tablet needs to reach the hydraulic section in seconds, and an outline is the difference between a usable manual and a PDF nobody opens twice. Building it locally also means the manual, which contains schematics the company does not publish, is never handed to an outside converter.

FAQ

Frequently Asked Questions

Can I create nested bookmarks with sub-sections?
Not currently. Every entry is written at the top level of the outline, so a list of chapters works well but a chapter-and-section hierarchy is flattened into one continuous list. A common workaround is to signal depth in the title itself — using a dash or a number prefix on sub-entries — which reads clearly enough in the sidebar even though the structure underneath is flat.
Will it detect my headings and build the outline automatically?
No. It creates exactly the entries you type and looks at nothing else in the document. Heading detection would require guessing from font sizes, which is unreliable across documents, so the design choice here is that you decide what belongs in the outline. Extracting the text first can help you find the right page numbers quickly.
The bookmark jumps to the page but not to the exact heading.
That is the destination type being used: entries are set to fit the whole page in the window, so a click lands at the top of the page containing your heading. If a section starts halfway down a page, the reader arrives at the top of that page and the heading is visible below. There is currently no option for a precise vertical position.
My PDF already has some bookmarks. What happens to them?
They are replaced. The tool writes a new outline into the document catalogue rather than appending to the existing one, so anything that was there before is gone. If you want to keep those entries, list them in the box along with your new ones and the whole outline is rebuilt in one pass.
Do I have to upload the document for the bookmarks to be added?
No. The document structure is modified by pdf-lib running in this tab, using a copy of the library stored on this site, and the rewritten file is handed back as a download. An unpublished standard or an unreleased manual never leaves the machine — you can watch your browser's network panel stay silent while the outline is written.
Why do some of my lines get ignored?
Each line has to be a number, then a vertical bar, then some text. Lines missing the bar, starting with a word rather than a digit, or pointing at a page beyond the end of the document are dropped silently so that a stray note in the box does not break the run. If nothing at all matches, you will get an error telling you the document's real page count.
Keep going

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