head to head · open source
KillerPDF vs Collabora Online
KillerPDF has 4,289 GitHub stars, 342 forks, 38 open issues and last shipped yesterday. Collabora Online has 3,389 stars, 1,014 forks, 874 open issues and last shipped 7 days ago. KillerPDF leads on adoption by 27% (4,289 vs 3,389 stars). KillerPDF is written in C# under GPL-3.0; Collabora Online is written in Shell under a custom or non-standard licence. KillerPDF has attracted 8% as many forks as stars, Collabora Online 30%. KillerPDF was the more recently maintained of the two, and both are self-hostable with no licence fee. The two share 2 topic tags (open-source, opensource), so they are genuine substitutes rather than adjacent tools.
Two open source projects, one decision. Both are free and self-hostable — the differences are community size, license terms, language stack and release pace.
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Side by side
| KillerPDF | Collabora Online | |
|---|---|---|
| GitHub stars | ★ 4.3K | ★ 3.4K |
| License | GPL-3.0 | Custom / other |
| Written in | C# | Shell |
| Last push | 2026-11-02 | 2026-10-27 |
| Forks | ⑂ 342 | ⑂ 1.0K |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick KillerPDF if
- You weight community size — 4.3K stars and counting
- You want the GPL-3.0 license terms
- Your stack matches C#
- You value the larger contributor base for long-term maintenance
pick Collabora Online if
- You want the Collabora Online feature set and don't need the biggest community
- You prefer the Custom / other license terms
- Your stack matches Shell
- You evaluated both and Collabora Online fits your workflow better
About KillerPDF
KillerPDF is a free, open source PDF editor for Windows. View, annotate, OCR, merge, split, edit text, draw, sign, fill forms, print, flatten, and open password protected PDFs without an Adobe subscription. Choose the compact Windows installer or the self contained portable edition. Document processing stays on your computer, with no telemetry. Full how tos live on the help page; internals, formats, and limits on the technical page. The KillerPDF.Engine KillerPDF 1.8 introduces The KillerPDF.Engine, an independent and reusable .NET library for PDF 2.0, PDF/A, and PDF/UA document processing. It is a first class…
read the full KillerPDF overview →
About Collabora Online
Collabora Online [!IMPORTANT] About this repository. Active development of Collabora Online has moved to our Gerrit instance at which is where the source code and code review live. This GitHub repository is kept for: Issue tracking — please report bugs and request features here. Release artifacts — the nightly container image, the Helm chart, and build assets are published from here. Source code changes go to Gerrit, not GitHub. Follow CONTRIBUTING.md and push to Gerrit instead. Pull requests here are welcome only for the parts this repository owns — the Helm chart and the docker image build. A read only mirror…
read the full Collabora Online overview →
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Frequently asked questions
Is KillerPDF or Collabora Online more popular?
KillerPDF has 4,289 GitHub stars and Collabora Online has 3,389. KillerPDF has the larger community by that measure.
Are KillerPDF and Collabora Online free?
Both are open source. KillerPDF is licensed under GPL-3.0, and Collabora Online has no licence declared in this registry. Both are free to self-host.
What is the difference between KillerPDF and Collabora Online?
KillerPDF is written in C# and Collabora Online in Shell. The practical differences are community size, licence terms, language stack and release cadence — all compared in the table above.
Which should I choose, KillerPDF or Collabora Online?
Choose KillerPDF if you want the larger community (4,289 stars) or its GPL-3.0 licence terms. Choose Collabora Online if its feature set, stack or Custom / other licence fits better. Both are self-hostable.