Redact a PDF

How to redact a PDF here

1. Open the PDF. Tap Choose a PDF, drop the file on the box, or paste it into the page where your browser allows pasting files. The pages appear at the width of your screen, with thumbnails above them.
2. Find what repeats. Type a name, word or number and press Find, or tap E-mail, Phone, IBAN-like or Card-like. Every match on every page gets a box and a line in the list; untick a line to leave that one alone.
3. Draw the rest. Drag on a page to draw a box (on a phone, tap Draw box first so a swipe does not just scroll). Drag a box to move it, pull a corner to resize it, tap Delete to remove it. Undo steps back.
4. Apply and download. Pick black or white boxes, press Apply redactions, read the summary, then Download redacted PDF. Open the download and try to select the text you covered: there is none.

What it cannot do

• Redacted pages become pictures. The words you did not cover on those pages can no longer be selected or searched. To get them back as text, run the downloaded page through Image to Text.
• The file grows. Each redacted page becomes an image: a full page of small print measured about 550 KB at 200 DPI as PNG (380 KB at 150 DPI, 950 KB at 300), a mostly empty page about 15 KB. JPEG is smaller only for scanned or photo pages; on sharp text it came out larger.
• Password-protected PDFs cannot be opened. If you know the password, remove it first with Unlock PDF (or in the program that set it), then come back.
• Text that is itself an image cannot be found. A scanned page has no text layer, so Find shows nothing there; draw a box over it instead.
• Attachments and form fields are dropped. On redacted pages, links, comments and fill-in fields go with the original page. The file is also rebuilt from its pages alone, so file attachments, bookmarks and the form's fill-in logic are not carried over on any page.
• Find places boxes from the text layer, not by looking. Box edges are worked out from each character's share of the line and padded; check them on the page before you apply, and stretch any that look tight.

Why a black box in a PDF editor is often not enough

Most leaked redactions have the same cause: a black rectangle was added on top of the text. The words are still in the page's drawing instructions underneath, so selecting the area, pressing copy, or searching the file brings them straight back. A highlighter set to black, a shape in a comment layer, or a black box in a word processor before exporting all leave the text in place.

This tool does it the other way round. For every page that has a box, it draws the page into an image with PDF.js (the viewer built into Firefox) at the resolution you choose, paints the boxes into the pixels, and writes a new page that holds only that image, using pdf-lib. The original page, its text, its fonts and its annotations are left out of the new file. Pages without a box are copied across unchanged with their text. Both libraries are pinned copies served from this page and load only when you open a file.

It also clears what the file says about itself: the document info fields Title, Author, Subject, Keywords, Creator and Producer and the XMP metadata stream (where editing programs record names, dates and history) are not written into the redacted copy. A worked example: a 12-page contract with a client's name twice on page 1 and once each on pages 4 and 11, plus an account number on page 4, gives 3 pages redacted, 5 matches, 9 pages untouched; the nine untouched pages stay searchable.

Questions

Is the text really gone, or just covered?

Gone from every page you redact. Such a page is replaced by a picture of itself with the boxes painted into its pixels, and none of its original text, fonts or drawing instructions is copied into the new file. Pages without a box keep their text, so box every page where the information appears; Find searches all pages at once.

Is it free, with no sign-up?

Yes: no account, no e-mail, no watermark, no page limit and no paid tier. The work runs in your browser, so there is no server cost per file.

How do I redact a PDF on an iPhone?

Open this page in Safari, tap Choose a PDF and pick the file in Files. Use Find, or tap Draw box and drag with your finger. Tap Apply redactions, then Download; the copy lands in Downloads in the Files app.

How do I redact a PDF on a Mac?

Open this page in Safari, Chrome or Firefox and drag the PDF from Finder onto the box. Drag with the mouse to draw boxes, use Find for anything that repeats, then apply and download. Nothing to install.

Does it work offline?

Yes, after the first file: opening it fetches the PDF engine from this site (about 1.9 MB). From then on you can switch to airplane mode and still search, draw, apply and download. The PDF itself is never sent anywhere.