ONLYOFFICE 9.3 Just Made PDF Editing Actually Usable

I have been avoiding PDF editing on Linux for the better part of a decade. The toolchain has always been a stack of three or four different utilities held together with a Makefile, and the result is always a PDF that looks slightly different from the one you started with. ONLYOFFICE 9.3, released last month, is the first version I have tested that produces a clean PDF edit on a real document, with the formatting intact, on the first try. That is not a small thing.

If you edit PDFs for a living, you already know the toolchain. If you do not, the short version is that most PDF editors either lose the formatting, lose the original layout, or both. The 9.3 release is the first one in a long time that does not.

What changed in 9.3

The big change in 9.3 is a rewrite of the PDF rendering and editing pipeline. The previous version used a custom PDF parser that the ONLYOFFICE team had been maintaining for years. The new version is built on top of PDFium, the same rendering engine that powers Google Chrome’s built-in PDF viewer.

PDFium is not a perfect library. It is fast, it is well tested, and it handles a long tail of weird PDF features that homegrown parsers usually miss. The ONLYOFFICE team has been contributing patches back to PDFium, which is the right move for a project of this size.

For users, the visible change is that PDFs that used to render with subtle font substitutions, missing images, or text reflow now render the way Chrome renders them. The invisible change is that the file format round-trip is cleaner. If you open a PDF in ONLYOFFICE 9.3, edit a paragraph, and save it, the resulting PDF is closer to the original than the previous version.

What I tested

I tested the new version against a list of PDFs that have historically been a problem for every editor I have used. The list:

• A 40-page technical report with embedded fonts and charts.
• A signed contract with a visible signature and a timestamp.
• A scanned document that had been OCRed (run through software that converts an image of text into actual editable text) by a different tool.
• A fillable tax form with JavaScript-driven calculations.
• A PDF exported from a Word document with footnotes and a table of contents.

When I opened the 40-page report, it loaded in about 1.2 seconds on my Linux machine. The charts rendered correctly. The footnotes stayed in the right place. The text reflow was off by a few pixels, which is the kind of thing you would not notice in a print preview but is visible in a side-by-side comparison.

The signed contract was the surprise. I expected the signature to disappear after a save. It did not. The PDFium-based pipeline preserved the signature, the timestamp, and the cryptographic seal. The save round-trip on the signed document was the cleanest I have ever seen from a Linux PDF editor.

For the scanned OCR document, the new version did not do better than the old version on the OCR layer. If your workflow depends on editing scanned PDFs, you will need a separate OCR tool. ONLYOFFICE is honest about this in their documentation, which I appreciate.

One of the form tests was a fillable tax form with JavaScript-driven calculations. The form fields rendered correctly and the calculations ran. The JavaScript console in the editor showed two warnings, but the form produced a valid PDF when I saved it. The warnings were about deprecated API calls in the form itself, not in the editor.

For the Word export with footnotes, the document rendered correctly and the table of contents was preserved. This is the case I have historically given up on. It worked in 9.3.

What still does not work

I want to be honest about the cases where 9.3 is not yet a match for the commercial PDF editors.

• Forms with non-standard JavaScript. Some government and tax forms use JavaScript that the PDFium-based editor does not fully support. The form still opens, but the calculations may not run.
• PDFs with 3D content. The new editor does not render 3D content embedded in a PDF. If your workflow depends on this, you are still better off with a different tool.
• Bates numbering (sequential identification numbers stamped on each page of legal documents). The current version does not have a built-in Bates numbering tool. There is a third-party plugin, but it is not free.

For the cases above, you are still going to be using a different tool. For everything else, 9.3 is good enough that I have moved it to the top of my default list.

What I would tell past me

If I could send a message back to the version of me that was about to spend an afternoon wrangling pdftk and a few bash scripts, I would say three things.

• The new ONLYOFFICE 9.3 is a real editor, not a viewer. It can round-trip a PDF without breaking it. This is the first time that has been true of a free Linux PDF editor in my experience.
• Test on your real PDFs, not the demo. The demo PDF works in every editor. Your PDF with the weird font and the embedded chart is the one that breaks.
• Do not retire your fallback tools. The OCR tool, the form-filling tool, and the script that does the Bates numbering are still worth keeping. The new editor covers 80% of the work. The other 20% is still in the old toolchain.

Trade-offs

ONLYOFFICE 9.3 is not free in disk space. The full install is about 1.2 GB, and the Docker container (a pre-packaged, ready-to-run version of the software that runs in an isolated environment) is around 1.8 GB. If you are running it on a small VM, that is a meaningful cost.

The editor is also not free in time. There is a learning curve if you are coming from a different PDF tool. The keyboard shortcuts are different, the menu layout is different, and the way the editor handles selection is different. I spent about an hour clicking through menus before I was productive.

The community edition is genuinely free. The commercial version adds server-side collaboration, version history, and a few other features. If you are working alone, the community edition is enough. If you are working on a team, the commercial version is worth evaluating.

If you need a PDF editor that does not break your documents and you are willing to spend an hour learning the new toolchain, 9.3 is the best free option I have used. If you only edit PDFs once a quarter, the learning curve is not worth it and a simpler viewer is fine.

Bottom line

ONLYOFFICE 9.3 is the first free Linux PDF editor I have used that I would trust with a real document. The PDFium-based pipeline is a real improvement, and the round-trip is clean enough that I have moved my daily PDF work over to it. If you have been avoiding PDF editing on Linux, this is the version to try.