Turn text-PDF page references into reviewed internal links. Find literal page references in a text PDF, review the destinations, and export a separate PDF with clickable internal links.
You have a manual, handbook or report saved as a text PDF, its cross-references (“see page 12”) are plain text, and you want readers to be able to click them.
Buy and extract the Bifrosta ZIP, then open its Bifrosta folder. Open app/index.html in desktop Google Chrome. The same workflow can be explored in the online browser preview.
In your open local copy, follow the controls described below. The five steps across the top are Document, Pattern, Calibration, Review and Export.
Under “1. Open a text PDF”, click Choose a PDF… or drop the file on the page. Bifrosta shows the page count and “text layer found”. The file is read in your browser and is never modified.
Under “2. Describe the reference”, type the words before the number in Text before the number (the default is “see page ”) and anything after it in Text after the number (optional). Ready-made examples such as see page 35, see p. 35 and (p. 35) fill the fields for you. Click Find candidates.
Under “3. Calibrate printed numbers”, Bifrosta suggests an offset between the printed page numbers and the pages of the file. If the suggestion is right, click Apply. Otherwise, under SET IT FROM ONE KNOWN PAGE, enter a printed number and the PDF page (sheet) it is on, then click the Use offset button. Books with a cover or front matter usually need an offset; confirm it on the page preview. Then click Review N candidates.
Under “4. Review every candidate”, each reference shows where it was found and the page it will open. Click Approve or Reject for each one, or Approve N unambiguous to approve all references with a valid target. References that point outside the document are blocked. Click Continue to export (N links ready).
Under “5. Save a linked copy”, optionally tick Draw a thin blue border around each link, then click Save <name>.bifrosta.pdf. Your browser downloads a new PDF. Click Save review job (<name>.bifrosta.json) if you want to resume or re-check the review later.
Open the saved copy in your PDF reader and click a few links to confirm each one opens the expected page.
Input: examples/bifrosta/balcony-herb-handbook.pdf: a fictional 6-page text PDF, numbered 1–6 in the footer, with seven “see page N” references. One of them points to page 9, which does not exist.
Expected: Bifrosta reports “7 candidate reference(s) found”, with 1 blocked: “see page 9” is out of range. Your browser downloads balcony-herb-handbook.bifrosta.pdf, which has the same 6 pages and 6 clickable links. For example, “see page 4” on page 1 opens page 4. The status line shows “6 link annotation(s) written”.
Bifrosta only accepts text PDFs. Scanned pages without a text layer and encrypted, damaged or digitally signed files are refused, and the reason is shown. Export the document again as a text PDF from the program that created it.
Copy the exact wording from the document preview in the Pattern step into Text before the number. Keep Ignore letter case and Tolerate different spacing and line breaks ticked.
The offset is wrong. Go back to Calibration, enter a printed number and the PDF page it appears on under SET IT FROM ONE KNOWN PAGE, then review again.
Bifrosta stores nothing in the browser. Save a review job before closing, then use Load review job… in the Pattern step with the same PDF to resume.
That folder belongs to the offline package and is not on the website. Use the example PDF from this guide instead.
Guide and examples: 30 September 2026. Examples are fictional or synthetic. Online guide · Support