Introduction
Most "PDF editors" online don't really edit the PDF. They lay a white box over the old words and type new ones on top, in whatever font they have handy. It looks fine until someone zooms in, copies the text, or notices the date is now in a different typeface from the rest of the contract.
The PDF Editor is built the other way round. It reads the fonts inside your file and writes your change with them. This post covers what that means in practice, what else the editor does, and the jobs it isn't built for.
Edit the text that's already there
Pick the Edit text tool, click any line and type. The editor reads the font embedded in the PDF, so the new words come out in the same font, size, colour and position as the old ones. Everything else on the page stays exactly where it was.
There's one catch, and it's worth understanding. A PDF usually carries only the letters it needed when it was made. If the document never used a capital Q and you type one, the file has no shape for it. When that happens, the editor draws the line with a close match from a library of more than 180 font families and tells you which font it picked, so it never happens silently.
While you're editing a line you can also make it bold or italic, change its size or colour, and align it left, centre or right.
You decide what happens with fonts
Open "Fonts in this document…" in the Document section of the Control Panel and you'll see every font the text uses, whether the file carries it in full, only partly, or not at all, and what edited text will be drawn with.
Don't like the automatic choice? Replace it for one block of text or for all text in that font. The picker shows ToolBuddy's own fonts, the fonts on your device if your browser shares them, and any TTF, OTF, WOFF or WOFF2 file you add. If a font isn't in any of those, the editor can download it from jsDelivr or Google Fonts, but only after asking you. That service sees your IP address and the font's name. It never sees your document.
Add what wasn't there
The Add group puts new things on the page. Anything you add can be selected, moved and resized, and its properties changed in the Control Panel.
- Text boxes with their own font, size and colour.
- Pictures in PNG or JPEG, such as a signature or a logo.
- Rectangles, ellipses, lines and arrows for pointing things out.
- Whiteout, to cover old details before you type new ones over them.
- Links to a website or to another page of the same document.
Comment like a reviewer
The Comment group is for marking a document up rather than changing it. Highlight, underline or strike out text, add a comment, draw freehand, add comment text, or place a stamp: Approved, Draft, Confidential, Final, Reviewed, Not approved, For comment, Void, your own wording, or a picture.
These are saved as standard PDF comments, so they show up in other PDF readers, where people can reply to them or remove them.
Your file stays on your device
The PDF is opened, edited and saved in your browser. Nothing is sent to a server, which matters when the file is a contract, a payslip or a medical letter.
There's a second, quieter benefit. Your edits are written as an update to the original file, so pages you didn't touch are saved byte for byte as they were. If the PDF has a password, you type it to open the file, and the edited copy keeps the same password and protection.
Features at a glance
Here's the short version.
| Feature | What it's good for |
|---|---|
| Edit text in place | Fixing a typo, a date or a price in the document's own font |
| Font control | Choosing what edited text is drawn with, for one block or the whole font |
| Text boxes, pictures, shapes | Adding a note, a logo or a signature picture |
| Whiteout | Covering old details before typing new ones |
| Links | Pointing to a website or another page |
| Comments and stamps | Reviewing a document the way other PDF readers understand |
| Incremental save | Keeping untouched pages exactly as they were |
Where it falls short
Better to know now than halfway through a job.
- Scanned pages are pictures. Their words can't be edited. You can still add text boxes, pictures, whiteout and comments on top.
- Some text sits inside graphics groups. A few documents keep their text there, and the editor can't change it yet. It tells you how many pages are affected.
- One PDF at a time. The editor edits a single document. It doesn't merge, reorder pages or fill forms.
- Memory is the limit. There's no page limit, but a very large file can be over what your device can open, and the editor will say so.
Who it's for
If you need to fix a typo in a signed-off brochure, update a date on a certificate, swap an address on a résumé, or mark up a draft for a colleague, and you'd rather not upload it to a site you know nothing about, this is the tool. It's free, there's no account, and nothing is added to your file.
Written by
Ankit Kumar
Senior Software Engineer & Founder at ToolBuddy
Engineering browser-first utilities with zero upload requirements using WebAssembly, Web Audio, and Canvas technologies.