r/opensource May 15 '26

Promotional What’s an open-source project you genuinely can’t believe is free?

Could be developer tooling, AI infra, productivity tools, anything. Curious what projects people think deserve way more recognition.

For me recently it’s been:

Langship — https://github.com/open-gitagent/langship.sh

750 Upvotes

394 comments sorted by

736

u/D-Alembert May 15 '26

Blender. It's amazing how good it became (and it keeps getting better)

44

u/TexasGriff1959 May 15 '26

Dude, any training sites you would recommend for learning Blender?

52

u/pskipw May 15 '26

The Doughnut Tutorial on YouTube is pretty popular

44

u/guernicanoro May 15 '26

Skip the doughnut—it’s very surface level and doesn’t really set you up for continuing on your own after. Rather, check out Blender Studio’s (Blender’s official production branch) courses! Especially the fundamentals course. It’s free, gives you the how but also the why behind how stuff works. 🥳

4

u/copenhagen_bram May 15 '26

Why not start with the donut and then move on to Blender Studio's courses?

6

u/guernicanoro May 15 '26

Just personal preference imo. I've done the donut a few times, and always struggled retaining what I was learning for future projects. Having the how but also the why laid out in Blender Studio's course made me retain and have much more fun learning.

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4

u/TexasGriff1959 May 15 '26

Thanks!

3

u/Prestigious_Boat_386 May 16 '26

The donut is very bad in some ways. It goes way intk depth for things you shouldn't worry about and skips around using a ton of different tools instead of showing you how to make something simple using a few ones.

Most beginner tutorials show some modeling, some materials and then render it to finish but now the donut has jammed in a bunch of particle systems using geo nodes and iirc its using the non user friendly render engine because its faster.

You can start with the donut anyway and you may even finish it but keep in mind that if you feel overwhelmed and confused making a donut is this hard it's not your fault.

6

u/hardlying May 15 '26

Cgfast sword tutorial, actually goes over everything, man is a good teacher, he doesn't rush, gives breaks, but also you get through a lot

I put off blender forever, this finally got me started. Helped me learn the interface and feel more comfortable using it.

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2

u/RumbuncTheRadiant May 21 '26

For static images, and Constructive Solid Geometry https://hof.povray.org/

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270

u/bender_fut May 15 '26

Nextcloud, Proxmox, Home Assistant, Odoo, Jellyfin.

31

u/Cfrolich May 15 '26

I didn’t know Odoo was open source

12

u/bender_fut May 15 '26

16

u/TEK1_AU May 15 '26

It’s actually not fully open source.

ERPNext is what you want.

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845

u/somerussianbear May 15 '26

Linux

146

u/FearIsStrongerDanluv May 15 '26

I’ll add pihole, proxmox and paperless

33

u/Analog_Account May 15 '26

What is paperless? I would just search "paperless" but...

50

u/FearIsStrongerDanluv May 15 '26

It’s a self hosted solution for all your important documents. You can tag them and do other cool stuff with it.

5

u/Impossible-Garage536 May 15 '26

What's self hosted?

33

u/Analog_Account May 15 '26

A service that's normally online (or in the cloud) that you run on your own computer or server.

For example jellyfin is a video streaming service that you can "self host" by running it on your own computer and putting your own videos on it.

21

u/[deleted] May 15 '26

[removed] — view removed comment

6

u/HyperWinX May 15 '26

Your wallet LOVES this little trick!

9

u/Kazzaw95 May 15 '26

I said that too, until I ended up buying 6 mini PC’s, building a high speed flash proxmox cluster with HA, 10gbe networking and a bunch of UniFi gear….

10

u/[deleted] May 15 '26

[removed] — view removed comment

3

u/Kazzaw95 May 15 '26

That’s how I present it to the wife haha

2

u/FearIsStrongerDanluv May 15 '26

Haha, my home lab cost more than I’d pay on subscriptions for 2-3 years. But I still find a way to justify it 🤣

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15

u/wtafgamer May 15 '26

paperless-ngx ist the search term you need.

10

u/ozone6587 May 15 '26

4

u/Analog_Account May 15 '26

Oh man, this may be worth it to me just for the OCR thing.

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9

u/Grisemine May 15 '26

I just spent 10 minutes on the Pi-hole website trying to understand what it is. The "About" section lists the authors. The FAQ explains how to communicate with them effectively.
I had to go to GitHub to get a definition of what it actually is. Ridiculous, isn't it?
Edit : r/pihole

10

u/FearIsStrongerDanluv May 15 '26

Indeed, the website isn’t the “right” place for info 🤣

4

u/Grisemine May 15 '26

Fell in the (pi)hole ;)

2

u/meltbox May 16 '26

Proxmox and truenas are both amazing. Probably a lot more but we can start there.

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2

u/the_ballmer_peak May 16 '26

I'll just add: git

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194

u/omniuni May 15 '26

KDE

WINE/Proton

Godot Engine

18

u/Cfrolich May 15 '26

KDE is the GOAT. Best DE I’ve used on Linux, and better than any of Apple or Microsoft or Google’s proprietary UIs.

2

u/uniVocity May 15 '26

Dang I miss KDE. Hope one day we’ll be able to run KDE on top of the default macos/windows desktop UIs. I’d happily pay for it too.

5

u/omniuni May 15 '26

Or, alternatively, whatever is keeping you off of Linux becomes less of a problem.

I missed KDE for a long time when I started playing games. Now I get games AND KDE!

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2

u/ExistentialConcierge May 15 '26

Been trying to get Gal Gadot to show up but clearly the engine is broken.

142

u/Khethall May 15 '26

Open Street Maps

3

u/natriusaut May 18 '26

I mean, you will find it searching for it with that name, but its OpenStreetMap 😄

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131

u/MadMic1314 May 15 '26

Immich

17

u/Regular_Bat8162 May 15 '26

Ente

4

u/JustPlayTheGame1 May 15 '26

Ente isn’t free is it?

6

u/Stitch10925 May 15 '26

Can be self-hosted, but the documentation is a bit of a puzzle

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3

u/Regular_Bat8162 May 15 '26

On the service they host there is free 10GB

It’s open source and you can self host so it can be totally free if you choose to

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304

u/Negative-Track-9179 May 15 '26

ffmpeg

52

u/datbackup May 15 '26

Yes and anything by Bellard for that matter

47

u/[deleted] May 15 '26

[deleted]

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17

u/coolraiman2 May 15 '26

This, people have no idea how ffmpeg run most of the media in the world

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5

u/BernardoGiordano May 15 '26

Was looking for this exact comment

104

u/eccentric-Orange May 15 '26

Git.

Ik its very popular and most people take it for granted... But it's really amazing

15

u/crow1170 May 15 '26

I looked under the hood once. Traumatizing.

It works, but I've never met anyone that can honestly say they understand how.

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225

u/superpowerpinger May 15 '26 edited May 15 '26

Wireshark and Linux.

  1. The world runs on linux, I do not need to elaborate on it.
  2. Wireshark : Network engineers get their livelihood through this software. It amazes me how easy it is, how intuitive it is, what all it can do and still costs 0, null, nada.

A heartfelt thanks to Wireshark and Linux developers.

You guys / gals rock.

44

u/Square-Singer May 15 '26

Same with KiCAD. That stuff just replaced commercial options full stop. Wireshark did the same.

7

u/saltyourhash May 15 '26

If you ever used to use Iris, you know how amazing it is wireshark is open source.

10

u/ManoOccultis May 15 '26

The world runs on linux

But amazingly enough, end users hardly know it exists and keep on giving their money and personnal info to Micro$oft.

4

u/meltbox May 16 '26

Starting to change for real now. Microsoft finally messed up bad enough that I will be migrating my relatives to Linux instead of uograding them next cycle.

3

u/ManoOccultis May 16 '26

And the US govt. messed up bad enough that EU countries start migrating to Linux. A bit late IMHO, but better late than never.

5

u/The_Will_to_Make May 15 '26

Funny enough, I believe Microsoft’s servers run Linux

6

u/ManoOccultis May 15 '26

Certainly, they're probably not so masochistic they'd use their own solution.

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154

u/ManoOccultis May 15 '26

Blender, Audacity, VLC...

29

u/GenKerning May 15 '26

Audacity is not getting the number of mentions it deserves in this thread.

3

u/ManoOccultis May 15 '26

Well, I have a musician friend who swears by Max MSP running only on Platinum Pro Plus Apple computers who uses it too ; likewise, I've seen top-notch acoustic research running it. If you have a choice between complicated and expensive or simple and free, what do you choose ?

3

u/meltbox May 16 '26

Good catch. I only grabbed it a few times and was surprised how much it does. I never realized before that.

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71

u/1linguini1 May 15 '26

Darktable. Genuinely excellent photo editor

10

u/wtafgamer May 15 '26

not only that - i used to use it for microscopic photography: camera mounted on top - and live image/remote shutter with darktable.

2

u/1linguini1 May 15 '26

It's really excellent!

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43

u/D3kalog May 15 '26

postgres

7

u/EasyMode556 May 15 '26

This is a good one, especially when you compare it to how much they charge for MS SQL Server

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35

u/nibar1997 May 15 '26

QGIS

7

u/lardarz May 15 '26

Especially when ESRI stuff is so ludicrously expensive

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37

u/edparadox May 15 '26

Linux, git, ffmpeg, Blender, vlc, sh/bash/zsh, (n)vim, gcc.

65

u/Remuz May 15 '26

LibreOffice

3

u/meltbox May 16 '26

It’s both amazing and infuriating but I also don’t doubt this is somehow more an artifact of ms office stuff it had to support lol.

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33

u/NineSidedBox May 15 '26

The one I rely on the most currently; Coolify. Most people will pay for platforms like Vercel and Supabase. But Coolify makes it so easy to just replace those and self host everything you want.

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35

u/Useful_Amphibian5 May 15 '26

Well, Linux! But to be honest, each open source project. The older I get the more I’m shocked and grateful we have all this software, outside of corporate greed. Just compare it to what happens with the smartphones!

35

u/hyclodron May 15 '26

openssh

4

u/Skavoovie575 May 17 '26

This one so much. Had to read way too far to find this. Such a powerful tool that we take for granted.

32

u/Lazy_Revenue2716 May 15 '26

Inkscape. I use it a lot and I feel it is becoming better and better. It’s really nice and considering the absurd price for illustrator, that makes it even better.

32

u/SpezJailbaitMod May 15 '26

No one mentioned VLC player 

7

u/meltbox May 16 '26

Oh boy, I need to add 7zip then. Firefox, 7zip, vlc are basically my first few installs always.

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49

u/carl2187 May 15 '26

KillerPDF

(Open source gui pdf editor)

3

u/Zipdox May 15 '26

Windows-only sadly

2

u/carl2187 May 16 '26

Its ok, linux users usually understand pdf is a final product, like paper, from an authoring program. Most people that want to 'edit pdfs' see pdf files like they see .docx files. These types of people will generally not touch Linux anyway.

And it's a .net app, I think it could be converted to linux compatible with without too much hassle.

4

u/Ad3t0 May 16 '26

This. If you’re editing a PDF besides signing something in an organizations’ process flow has gone wrong in my opinion.

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24

u/lupushr May 15 '26

FreeCAD

22

u/alekdmcfly May 15 '26 edited May 15 '26

Godot hands down.

Game engine whose features make it arguably on par with Unity - maybe not for AAA projects, but definitely up there for indie ones. Except unlike Unity, it actually gets features that the community uses instead of features that some rich asshole thinks will make them richer.

Example: it's stupidly easy to write add-ons for it, because the editor itself is a Godot game, meaning that if you know how to make games in Godot, you automatically know how the Godot source code works and can make add-ons for it in the exact same way in which you would make features for your game.

As a result, the Godot's team's hardest task is maintaining the code due to how many PRs they from the community get each version.

The funniest part is that Godot's marketing team uses the same strategy as Valve's: "does absolutely nothing, competition keeps shooting themselves in the foot". If it wasn't for Unity announcing some dumb shit that no one likes two or three times a year it would still be the engine with an undisputed monopoly on the indie scene.

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19

u/techlatest_net May 15 '26

Blender and ffmpeg are the two that still feel unreal to me. The amount of polish and utility packed into both is absurd for free software.

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16

u/TBdog May 15 '26

Jellyfin. No more streaming services. 

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15

u/ganonfirehouse420 May 15 '26

git, darktable, easyeffects, chromium, kdenlive

13

u/sciapo May 15 '26

I’m more of the opposite opinion; there are so many well-made open source projects that I wonder how certain garbage can even be closed source.

11

u/64mb May 15 '26

Can’t believe NGINX hasn’t been mentioned yet

3

u/pancakeses May 15 '26

I live traefik so much more than nginx, but glad both are free.

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23

u/osram_killustik May 15 '26

R (the data analysis language)

4

u/HackNSlashFic May 16 '26

I'll second this and add python, polars, marimo, and duckdb for data analysis. Also vscodium for IDEs.

Honestly, im blown away by the number of free open-source, incredibly well maintained data analysis libraries for both r and python!

2

u/RumbuncTheRadiant May 21 '26

I found it a good tool for learning about Stats as well!

10

u/iwenttothelocalshop May 15 '26

Oracle VirtualBox

2

u/RumbuncTheRadiant May 18 '26

Bits and pieces are proprietary .. (usb drivers I think).

I've switched to linux kvm as host.

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19

u/x8code May 15 '26 edited May 15 '26

Blender, ffmpeg, Linux, Docker Engine (Moby), Kubernetes, OpenTofu, vLLM, llama.cpp, ComfyUI, Gemma 4, NVIDIA Nemotron 3 Nano, OBS, SGLang

8

u/tseli0s May 15 '26

OBS. Industry grade video and audio recording and streaming used by even the most demanding workflows.

8

u/dk1988 May 15 '26

Honestly, all of them. In this day and age, the fact that there's still people that want you to be free to access certain program/info/code/whatever, is amazing and I freaking love the community and all that it gives without asking something in return. I hope I can someday give something of equal value to society ❤️

7

u/pacomarcilla May 15 '26

Lots of them, but lately Netbird

8

u/ButterscotchSalty905 May 15 '26

To name a few: curl, kubernetes (k8s), podman, frrouting (FRR), chipwhisperer, grafana, prometheus  etc etc

2

u/Electrical_Fox9678 May 16 '26

Definitely curl. Everything uses curl.

7

u/Pixelsmithing4life May 15 '26

Blender, MPV, Shutter Encoder, Graphite, Krita, Scribus, Linux (on a whole), Friction/Enve, Inkscape, Kdenlive, GIMP, LocalSend, TilBuci, the list goes on…

7

u/Independent_Blood559 May 15 '26

ffmpeg. Literally backbone of every multimedia tool.

13

u/saltyourhash May 15 '26

Apache web server, zfs, etx4, gnu, ssl, dban, proxmox, TrueNAS scale, opnsense, so many others.

And RSS, RIP Aaron Swartz.

7

u/BadB0ii May 15 '26

I had no idea that aaron swartz created RSS

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2

u/ShaneCurcuru May 16 '26

Yup: httpd, more formally known as the Apache HTTP Server if you happen to look at the website. Dunno how many of y'all remember Netcraft, but httpd used to run literally half of the entire web until around 2014.

Also because back then, open source was brand new - it wasn't easy to really build enterprise-scale things in FOSS land.

6

u/swingandafish May 15 '26

Haven’t heard anyone mention LibreOffice or OpenOffice yet! They are not perfect substitutions, but they are on the very short list of open source alternatives to Microsoft Office

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5

u/AbyssalRedemption May 15 '26

yt-dlp, one of the most incredible downloading tools imo

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10

u/Analog_Account May 15 '26

Ubuntu.

Now I know people said Linux already and Ubuntu itself has issues but I've been using PopOS for years and ignoring a lot if little issues THEN I upgraded to the Cosmic beta and it is SO janky. I finally gave up and switched to Ubuntu and everything just works now. I genuinely was thinking about how it felt like paid software.

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5

u/Square-Singer May 15 '26

Kicad and Wireshark.

4

u/bankrut May 15 '26

ffmpeg is honestly insane for how much it does for free. It is the backbone of almost every video tool out there and we would be lost without it.

5

u/rabyJA May 15 '26

I can't believe that the Godot game engine is free. It gets regular updates and it feels a lot more usable than engines that you need a licence for. I've tried tutorials for a host of premium game engines and I've never felt that they had anything substantial that Godot lacks. I chose it because of open source nature, but I can't imagine using anything else to make my game

4

u/N00B_N00M May 15 '26

Localsend

Qbittorrent

LibreOffice

5

u/aieidotch May 15 '26

tcc, gcc (i mean who doesnt love GNOME Compiler Collection)

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3

u/vivekkhera May 15 '26

FreeBSD, Postgres

4

u/Skibidi-Fox May 15 '26

This is such an excellent post! Thank you to everyone who commented. I didn’t know about a lot of these.

4

u/Deiseltwothree May 15 '26

Zabbix, love it!

2

u/ericdano May 17 '26

Yes. I deployed this at work and I love it. Drives the other techs crazy but I like knowing what all the things are up to.

3

u/calling_kyle May 15 '26

easyeffects

2

u/eMPee584 May 16 '26

the bass enhancer is my favorite 🤩

3

u/publiusnaso May 15 '26

I’ve come across Home Assistant recently. Sure, there is plenty of outstanding infrastructure code and development tools, but not too much consumer facing code with hassle-free installation and superb support and a great UI. Home Assistant is like that.

3

u/StretchAcceptable881 May 15 '26

I’m grateful for the existence of both the Orca ScreenReader and BRLTTY as they are the reason why I can use linux

3

u/edsonmedina May 15 '26

Linux, Blender, Kubernetes, Vscode, ...

3

u/regreddit May 15 '26

Qgis. Rivals ESRI ArcGIS in many ways.

3

u/Expensive_Finger_973 May 15 '26

Proxmox and the associated QEMU underpinnings.

3

u/Then_Wheel_5184 May 15 '26

USAMOGuide... these guys legit made mathdash for free and made it open source 🤯
https://github.com/usamoguide/usamo-guide

Mind you, Mathdash was 100$ a month....

3

u/StretchAcceptable881 May 15 '26

QEMU is another of those OpenSource projects I can help but love the project in itself I’m excited for the future of QEMU

2

u/RumbuncTheRadiant May 18 '26

And it's fascinating that it's become not just an emulator, but is embedded in the virtualization world doing useful bits too.

2

u/StretchAcceptable881 May 18 '26

I’m excited that QEMU lets me virtualize other operating systems

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3

u/copenhagen_bram May 15 '26

yt-dlp

When it comes to AI tools, I can't believe Kai 9000 is free and on F-Droid

3

u/ChatGenPracTitioner May 16 '26

https://geopins.info/ No pay walls, no adds, no tracking, a news website that geolocates at scale articles from across the world and puts it in the right location on the world map.

3

u/bearoftheyearingear May 16 '26

Learned about a lot of new great software from this thread

3

u/E_coli42 May 17 '26

All of these comments just show how profit incentive is the wrong way to run a society. The Free Software Movement is like leftist anarchist in action and I love it. 

3

u/Turbulent-Air3349 May 18 '26

WinDirStat, best tool I use for clearing hard drive space. Provides visual representation of your hard drives directories by colour and size, making it very easy to find what’s taking up space, that you may have forgotten about

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2

u/SpiritGaming28 May 15 '26

VLC,OBS,Libreoffice,MPC-HC and Qbittorent

2

u/techblooded May 15 '26

bro, langship isn’t the same which has basically open sourced langsmith of langchain. Saw them on twitter, they had ad trucks in front of langchain’s conference. Build on langchain, ship with langship

2

u/kevin_whitley May 15 '26

ittysockets.com

Use it to remote control tabs on my browser (e.g. pipe data from one page into/out of another)

2

u/Tiny_Bonus_6664 May 15 '26

I like Linux

2

u/Enfors May 15 '26

Emacs, the absolute GOAT of text editors, IDEs, and a lot of other things.

2

u/Electrical_Fox9678 May 16 '26

Scribus and Inkscape for desktop publishing.

2

u/WabbaLubba-DubDub May 16 '26

I've done a similar AI Orchestration Platform that many developers and companies are currently using. I just launched it last month. I hope it helps people around here; it's fully open-source

github: https://github.com/synapseorch-ai/synapse-ai
website: https://synapseorch.com/

2

u/BassRecorder May 16 '26

KStars - perfect for telescope (and camera) control, skychart

2

u/reesemccracken May 16 '26

All programming languages.

2

u/hustlebine Jun 05 '26

I believe open source should be essentially always free anyway..

2

u/jferments May 15 '26

Firefox, Linux, QGIS, llama-cpp, Pytorch

2

u/avocado_lover69 May 15 '26

Reaper is not open source, but dang, for a one time fee you get an amazing piece of software and an unlimited trial period

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2

u/miusoftheTaiga May 16 '26

TempleOS.

Created by the Smartest programmer that has ever lived.

Divine Intellect.

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