Okular
KDE's free multi-format document viewer for PDF, EPub, comics and images.
Where your files are processed
No server involved
An installed desktop application with no service component. Documents are opened, rendered, annotated and saved on the local machine.
Inherent to the technology rather than a vendor claim: an installed desktop application with no service component, so documents are opened, rendered, annotated and saved on the local machine.
What it does
Okular is the KDE desktop document viewer. It opens PDF plus a long list of other formats, and supports native PDF annotations, form filling, text selection, and viewing, verifying and creating digital signatures. It is a reader rather than a PDF content editor: what it can change in a PDF is annotations, form fields and signatures, and it can write those back into the file.
Best for: Linux desktop users, and Windows users who install it from the Microsoft Store, who want a free GPL reader with strong annotation and signature support.
Worth knowing: It annotates rather than edits — existing body text and page content cannot be changed. macOS builds are offered only as untested nightlies even though KDE's own API documentation lists macOS as supported.
Details, and where each comes from
Vendor statements, our own reading of their pages, and the things nobody has established yet, each answered separately. Where we have not confirmed something it says so rather than guessing, and a row nobody has established is greyed out.
- Versions covered
- Linux · Windows · macOS
- Website
- okular.kde.org
- Requires an account
- No
- Watermark on the free tier
- No
- Maximum file size
- Not verified
- Batch processing
- Not verified
- Data residency
- Self-hosted
- Open source
- Yes
- Self-hostable
- Yes
- Licence
- GPL-2.0-or-later
- Redaction
- No redaction feature
- Programmatic access
- None
- Last availability check
- Responded in 604 ms 16 October 2026
Checked automatically by our own runner, not reported by the vendor. 100% of our last 30 checks got a response.
What the redaction verdict rests on
From the vendor's own documentation, read 22 September 2026. Not tested by us.
What that does not establish: The vendor’s own site was read on 22 September 2026 and contains no mention of redaction, sanitisation, blackout or whiteout. Absence from a vendor’s own material is not proof that a feature does not exist — it may be undocumented, or on a page the reading did not reach — but for a NEGATIVE claim it is the strongest evidence available, and it is weaker than a positive quote. Recorded as such rather than presented as certainty.
What the vendor says
Claims are labelled rather than repeated as fact. Where we have checked something ourselves, it says so and shows when. Checked means we read the vendor's own page and it says what we recorded — not that we tested the behaviour, unless the note says we did.
-
“Okular is released under the GPLv2+, and is thus fully Free Software.”
Checked by us — the source says this Read 22 September 2026
Confirmed verbatim: the sentence appears unaltered under a heading reading "Free Software", and the page points to the source repository on KDE's GitLab. "Fully Free Software" is the vendor's phrasing of a licence position rather than a legal term, but the licence named in the first half of the sentence — GPLv2+ — is a specific and checkable fact, and the page states it plainly. Recorded as the project's description; the licence file itself was not read for this entry.
Standing: Re-read and matched byte for byte
Check it yourself: the source, the SHA-256, and how we checked
- From
- the text a browser renders
- SHA-256
- e57b020df1c20ab5195703fa642996b2c33e7e15cb826160508147fdfa0a0812
How we checked: Re-verified verbatim on 2026-09-22: https://okular.kde.org/ re-rendered in headless Chrome with scripts/render-page.mjs and the claim's wording found in the rendered text. Originally verified on 2026-09-21. sourceHash is the SHA-256 of the re-rendered text, held as rv-okular-kde-org-63952c72.txt.
-
“Okular can view and annotate documents of various formats, including PDF, Postscript, Comic Book, and various image formats.”
Checked by us — the source says this Read 22 September 2026
Confirmed verbatim: the sentence appears unaltered in the project's description, and the sentence after it is the useful qualification — "It supports native PDF annotations", which distinguishes real PDF annotation objects from annotations held in the viewer's own sidecar file. For a reader who needs to hand a marked-up PDF to somebody else, that distinction decides whether the marks travel with the document. This is the second Okular claim in the index, after the GPLv2+ licensing one, and the two were read from different pages of the same project.
Standing: Re-read, and the recorded hash was not reproduced
Check it yourself: the source, the SHA-256, and how we checked
- From
- the text a browser renders
- SHA-256
- 18cee36fd9894624c5bdb6c7bd27d4631a6def57e11d255aa5382214fe1f3db6
- Note
- unstable values: the project page reports "11,808 Commits 191 Branches" where it now reports "11,809 Commits 190 Branches", and the normalised texts still differ by 55 characters, so something else on the page moved as well. Not resolved.
How we checked: Re-verified verbatim on 2026-09-22: https://invent.kde.org/graphics/okular re-rendered in headless Chrome with scripts/render-page.mjs and the claim's wording found in the rendered text. Originally verified on 2026-09-21. sourceHash is the SHA-256 of the re-rendered text, held as rv-invent-kde-org-graphics-okular-76a9f175.txt.
Each claim is quoted from the vendor's own pages. This section describes what we have and have not checked — it is not a judgement about anyone.
Sponsorship is distribution, not an endorsement or a promise of search rankings, AI citations, traffic, or sales. This listing is a free entry, compiled from published sources.
Related reading
- Which PDF tools keep your file on your machine — what we count as processing on your own device.
- Open source PDF tools, and what their licences require — what open source does and does not tell you.