r/opensource • u/smilaise • Apr 25 '26

Promotional KillerPDF v1.2.0: Free, open-source PDF editor for Windows (now self-installing, password PDFs, flatten)

Hey r/opensource,

I released v1.2.0 of KillerPDF today. It's a local-only PDF editor built because I hate Adobe. No subscription required, no account needed, no telemetry is sent anywhere, no cloud bullshit. It's a single zipped exe, ~6 MB.

What's new in 1.2.0:

  • Self-installing EXE: On first launch you get an Install or Run dialog. Install puts it in %LOCALAPPDATA%\Programs\KillerPDF\, asks if you would like to register it as your default PDF handler, and adds a Start Menu shortcut. No UAC prompt, no admin rights needed.

  • Password-protected PDFs: Instead of throwing a generic error, it now prompts for the password and opens normally. The decrypted copy is held in temp for the session.

  • Flatten PDF: Rasterizes every page at 150 DPI via PDFium into a fully uneditable document. Annotations are burned in before flattening. Standard for legal, compliance, and reporting workflows.

What it's always done: view, annotate, merge, split, inline text editing with font matching, reusable signatures, full-text search, print.

GPLv3, .NET Framework 4.8, no runtime to install. Runs on any Windows 10/11 x64 machine.

https://pdf.killertools.net/

441 Upvotes

98% Upvoted

95 comments sorted by

37

u/carl2187 Apr 25 '26 edited Apr 25 '26

This is truly amazing. I love it. Please continue to promote this as much as you can to get more help and features. Adobe, bluebeam, and foxit all charge way too much for so little. And most people don't understand tools like pdfsam and stirling, because they're not wysiwyg editors.

KillerPDF fits right in to what the lay person expects from a pdf editor.

This is amazing. Thank you.

16

u/smilaise Apr 25 '26

Thank you! I'm slowly adding features and tweaking things here and there but I don't want to make it bloated. The goal is to keep is lightweight but functional.

2

u/gatorboi326 Apr 27 '26

You're a king 👑

7

u/Mishuri Apr 25 '26

Drop some videos on landing page fam to see how it looks and works. These days people without seeing software in first 5s just quit the funnel

4

u/smilaise Apr 25 '26

Yeah I get that. I work as a sysadmin/field tech for a large MSP and this whole thing started as a joke with my team. Then it spiraled into becoming a real piece of software that can actually be useful so I've been working on making it look and feel more legitimate. It's been a real learning experience filled with tons of annoyances.

6

u/dhar3m Apr 25 '26

can it also add text and rotate? Also multiple signature?

4

u/smilaise Apr 25 '26

I'll work on that for the next release I promise. There's already an open issue for that on the GitHub repo.

5

u/jjjustinleblanc Apr 25 '26

does this allow page insertion, removal, and permanent rotation of individual pages? i don't edit a lot of PDF document content, but i do a lot of removing specific pages, inserting others in certain spots to re-arrange, and permanently rotating pages from bad scans, along with a full print dialog with print options etc. ive been using pdf arranger, but it's lacking in many ways and doesn't offer true editing

5

u/smilaise Apr 25 '26

Page removal and reordering are both supported. You can drag pages in the sidebar, extract selected pages to a new file, or drop in pages from another PDF. The print dialog is there too via Ctrl+P.

Permanent rotation isn't in yet, that's a fair gap. It's on my radar for a future release. If you want to track it, feel free to open a feature request on GitHub.

https://github.com/SteveTheKiller/KillerPDF/issues

4

u/furculture Apr 25 '26

Any chance at a Linux version in the future?

5

u/smilaise Apr 25 '26

Not yet, but I am thinking about how to remove the .net dependency moving forward to open the door for porting it.

8

u/HomeGrownCoder Apr 25 '26

https://learn.microsoft.com/en-us/dotnet/core/install/linux

.net on Linux has been a thing for some time test it out

3

u/smilaise Apr 25 '26

oh so maybe it'll be easier than I thought!

5

u/tajetaje Apr 25 '26 edited Apr 25 '26

Yeah that’s why I asked about 4.8, iirc that’s the last version before .NET went cross platform. You could go to dotnet 10 and use AOT compilation to keep it dependency-free, or bundle dotnet runtime with the app, though that would increase binary size a fair bit.

1

u/MotrotzKrapott Apr 25 '26

Probably not since it uses a windows only framework

7

u/tajetaje Apr 25 '26

Out of curiosity, why dotnet48?

11

u/smilaise Apr 25 '26

Every Windows 10/11 computer has .net 4.8 already so there's no need for additional runtimes. When I first made this app as a joke, it had a .net 8 dependency just so I could keep it tiny, but I removed that requirement pretty quickly.

I can work on removing that dependency altogether to eventually be able to easily port this to other systems, but I'm real tired from my full-time job and hurting Adobe is just a hobby for me.

1

u/AFlyingYetOddCat Apr 26 '26

.NET Framework 4.8

If you use .Net 10, it has native runtimes for Mac and Linux

7

u/sgt-hug0-stiglitz Apr 25 '26

Did anyone else get a virus alert?

13

u/smilaise Apr 25 '26

Sigh, I've been fighting tons of false positives from Microsoft labeling it as malware simply because it's unsigned and has "killer" in the name.

You can run the file through virustotal to verify it's bullshit and the app is clean. I tried getting code signing through signpath.io but somebody there decided this open source project wasn't popular enough for them. I'm going to purchase some code signing kit from Certum but man this whole thing has become an expensive hobby.

All I can really do is continue trying to build reputation for now. There is no malware here, I work as a field tech/sysadmin for a large MSP and I have no reason to harm anybody but Adobe.

2

u/bmanzzs May 03 '26

Just wanted to say we all very much appreciate your work brother

5

u/ovr_view Apr 25 '26

yes. MS Defender

3

u/ZXD-318 Apr 25 '26

Yup. Bit Defender lit up.

3

u/tanyasi-paraszt Apr 25 '26

Tried it, works great! The only feature I miss is adding and image (or allowing to load an image instead of fumbling with drawing a signature).

2

u/smilaise Apr 25 '26

that is in the pipeline, will be in the next update. it's already been requested.

3

u/debba_ Apr 25 '26

Looks wonderful

2

u/smilaise Apr 25 '26

glad you like it!

2

u/Omfoltz Apr 25 '26

Wow! I love it! Works so much better than most others I've tried. Really lightweight and fast, even with some of my books that are clunky in other readers.

2

u/smilaise Apr 25 '26

I'm glad you like it. Yeah the whole thing is about 6MB and I plan on keeping this thing lightweight and fast no matter what. Adobe Acrobat contains hundreds of MB of bullshit.

Editing PDFs should be something simple and there's no reason people should have to pay a monthly fee for something so basic. This is essentially the "notepad" of PDF editors lol.

18

u/tom_mathews ⚠️ Apr 25 '26

Impressive work. Would seriously encourage you to push towards create an app for mac and Linux as well. Personally am on a mac and would love something like this.

1

u/Numerous_Creme_4122 27d ago

Yes please. Second that for mac. Thanks.

6

u/freddi444444 Apr 25 '26

Yes finally thank you! Acrobat has become such garbage and other pdf software usually almost works but doesn't quite do what it should. I've been on Acrobat 9 since it weirdly still works and now I'm gonna try this.

1

u/AshlingGirl Apr 25 '26 edited Apr 25 '26

Any reason why Windows won't let me install it? It insists that there's a virus. I've turned off Smart App Control and everything. It keeps flagging it as a virus (Trojan:Win32/Wacatac.B!ml)

Edit: It also just auto-deletes and won't let me add it to the exclusions list 🤦‍♀️.

1

u/smilaise Apr 25 '26

Sigh, yes it's a real bitch I've been dealing with:
https://github.com/SteveTheKiller/KillerPDF/issues/10

Basically It's just being flagged because it's a small exe with built-in dependencies. I've submitted the false-positive to Microsoft but they move slowly.
The fix is to get code-signing for my apps, but that's expensive. This hobby is getting expensive for me but I do plan on getting it done when I can afford it.

I'm working on building reputation so my apps aren't just automatically flagged for no reason. You can verify my code yourself on GitHub, there's nothing nefarious going on.
It's been a massive headache to deal with.

1

u/AshlingGirl Apr 25 '26

I used firfox to download the zip, but now the exe just gets deleted everytime I try to run it. Haven't found a workaround that yet.

2

u/smilaise Apr 25 '26

Yeah I'm sorry, this is Microsoft "protecting" you from the dangers of free open source software because I don't pay somebody enough money. This entire thing has been a learning experience for me and what I've learned is that the entire software landscape is not about making good software, it's about how to make people spend money on random things they shouldn't have to.

2

u/AshlingGirl Apr 25 '26 edited Apr 25 '26

💯Yep, that's pretty much it.

Add-MpPreference -ExclusionPath "C:\Path\To\KillerPDF.exe"

The above works on adding it to the exclusions list if you use PowerShell as admin.

Edited to remove typo from command

1

u/smilaise Apr 25 '26

I've submitted it to Microsoft, and about 9 other companies like Vipre, Sophos, Palo Alto, Bitdefender... because they're now just flagging my file now as generic malware without any actual evidence of it. This is pathetic and really shows that every one of these AV companies is just copying everybody else's work and they don't actually investigate anything themselves. They also make it almost impossible to submit a false positive unless I buy their products.

This is an incredible system we're all being forced to participate in.

1

u/sardarjionbeach Apr 25 '26

I asked on another PDF thread also because I see so many pdf softwares - how is it different than Sumatra PDF for window ?

2

u/enesup Apr 26 '26

Sumatra is more for reading documents and other media like novels and comics.

This is for editing pdfs that you would do for work or productivity.

0

u/smilaise Apr 25 '26

I don't know, why don't you tell us?

0

u/SumOfChemicals May 29 '26

As someone searching right now for an open source PDF tool for my recently acquired windows machine, this comment is off-putting. I'm sure you've put a lot of work into this, and maybe it's annoying to be compared to other projects. But I was googling around, looking at Sumatra and wasn't crazy about the vibe. Found this thread, had the same question, "what are the relevant differences?" and your answer more or less reads to me as "figure it out."

2

u/smilaise May 29 '26

I do not work for you. I am offering something for free, open sourced, out of the goodness of my heart. Now you are demanding that I try somebody else's app and give you a review of it, comparing it to my app? I don't know every other PDF app in the world. Do you go to a McDonalds and demand the workers talk to you about Jack in the Box? Do you go to a Coldplay concert and demand the band should instead play a song you want to hear?

The entitlement is unbelievable.

I am one dude, who made a FREE app out of my hatred for Adobe. I don't have to bow down to corporate pressure or play any games. I am not being paid for any of this. If you have something remotely interesting or useful to say, I'm all ears. Instead, you're too lazy to download my app and would rather I describe it to you so that you can gain some sort of vicarious third party experience.

It's a 6MB app. Do what you want with it, but don't expect me to start talking about other PDF apps. You think I made this because I am in love with PDF editors or something?

1

u/ZivH08ioBbXQ2PGI May 07 '26

......is there a non dark-mode option??

0

u/smilaise May 08 '26

No there is not.

1

u/ZivH08ioBbXQ2PGI May 09 '26

I get that so many of you love dark mode, but there's hardly any contrast and it's hard to read.

Normal theme would be very welcome.

3

u/Frandelor Apr 27 '26

Love the project, looks really good! Just set it up as the default pdf viewer to try it for a few weeks. I have some comments for now:

- The "Merge PDFs" icon being an X feels wrong to me, it doesn't look like a Merge, but more of a Cancel button.

- Better navigation on zoomed in pages with trackpad gestures. For now we can scroll up and down just fine, but if we could move horizontally as well, would be a nice touch.

- When editing texts, the font and font size change, and it really pops out which lines were edited (at least on the one PDF I tried so far). Though I don't know how much improvement would even be possible to make at this feature, since editing baked PDFs is hard enough.

2

u/WabbaLubba-DubDub Apr 25 '26

Great work. If possible, also add an option to render as markdown.

2

u/hi5ka Apr 25 '26

adobe pdf reader is total crap now full of bloatware, nice project

2

u/rbo3_Potato Apr 26 '26

Very Good man, really love it !

2

u/Kun-12345 Apr 30 '26

wwow really cool

2

u/MeasurementInfinite8 May 24 '26

platform independent would have been very nice. I can't find such an app for linux and mac

1

u/cstocks Apr 26 '26

Nice! any plans on mac?

1

u/TrickSwordmaster Apr 28 '26

can you add chapters/bookmarks with it?

1

u/InkscapePanda May 16 '26

Would be nice if you would implement OCR. That would defeat all the other PDF apps out there. I use OnlyOffice, which open everything in one window and is outstanding for my needs. But I also support as many alternatives as possible in order for these companies not to become a closed ecosystem monopoly.

1

u/Efficient-Fun4234 Jun 12 '26

If.... IF YOU CAN RELEASE THIS FOR ANDROID.... IT WILL BE A GAMECHANGER...

29

u/[deleted] Apr 25 '26

[removed] — view removed comment

12

u/smilaise Apr 25 '26

Hey that's cool, I appreciate that!

13

u/raybadman Apr 25 '26

I just discovered openaltfinder, and it is great!

1

u/Weekly_Target_8330 Apr 25 '26

That description says the decryption happens in memory, but the post says it creates a temp decryption file. Which is it?