RedPen · PDF Text Editor

A single-file, in-browser PDF text editor. Open a PDF, click any line to rewrite it, add new text anywhere, and export a fresh PDF. Everything runs client-side — no server, no uploads, nothing leaves the browser.

Live demo

Once GitHub Pages is enabled (see below), it runs at:

https://<your-username>.github.io/<repo-name>/

Deploy in three steps

1. Create a new GitHub repo and add these two files at the root:
   • index.html
   • README.md
2. Go to Settings → Pages.
3. Under Build and deployment → Source, pick Deploy from a branch, choose main (or master) and the / (root) folder, then Save.

Give it a minute, then open the URL above. That's it.

How to use it

• Open PDF — every page renders on screen.
• Click a line of text — it becomes editable. Rewrite it, or clear it to delete that text.
• Add text — click anywhere on a page to drop in new text.
• Cover / Ink — the fill color used to hide the original text, and the color of your new text.
• Export edited PDF — downloads edited.pdf with your changes baked in.

How it works

Edits are made by covering the original text with a filled rectangle and redrawing your version on top. This is clean on white pages and simple layouts (letters, invoices, forms, most Word / Docs / Pages exports).

Expect some drift on:

• Colored or textured backgrounds — match the background with the Cover color picker.
• Rotated text or tight multi-column layouts.
• Exotic embedded fonts — redrawn text falls back to a close standard font (Helvetica / Times / Courier).
• Scanned PDFs — those are images with no text to grab, so there's nothing to edit.

Built with

• pdf.js — rendering pages and reading text positions.
• pdf-lib — writing the edited PDF.

Both load from a CDN, so the page needs an internet connection the first time it runs.

License

MIT — do whatever you like with it.