Wait, has no one mentioned LibreOffice yet? 200 million active users (!) seems like it's successful enough. Admittedly, it hasn't really challenged Microsoft Office yet, but it's growing, and also it's hard to look at something with 200 million active users and say 'that's a failure'. Definitely an alternative though.

There's also uBlock Origin, but I don't know if it's the largest adblocker yet. It should be, though. I think it is a serious competitor, even in terms of market share, to many major for-profit adblockers.

Early days torrent scene ran on proprietary adware clients like BitTorrent itself, µTorrent, and BitComet but nowadays open source clients are more popular and recommended by most trackers. I'm on a pretty big private tracker and almost everyone (+95%) is using qBittorrent, Transmission, or rTorrent.

Though Vuze was also one of the earliest clients and it's also open source for some reasons it never really became popular. Maybe because it's a Java client?

OBS Studio - I found this to be a very valuable and successful application for video and audio editing, with some amazing companies sponsoring them. - https://obsproject.com/

With how anti-consumer the recent Plex moves have been, Jellyfin [1] has gotten really popular among self-hosting community. It is arguably the best alternative to Plex in terms of features and the amount of freedom given to the user.

[1] https://github.com/jellyfin/jellyfin

So much, I know a lot of these have already been said so forgive me if I repeat some that others have said,

- 80-90% of the web's servers (something like nginx 35%, Apache 30%, cloudflare 20% who I believe run Linux for a large chunk of their infrastructure, litespeed 10%)

- stock market. I've read a number of articles discussing how NYSE, Tokyo, and NASDAQ run their trades and servers on Linux.

- internet infrastructure: From Linux to ssl to VPN sooooo much of internet's infrastructure is open source. From the servers to the protocols to the stacks. I don't have hard numbers but I'd be comfortable guessing at least 3/4 of the net's infra is open source.

- Git

- Firefox

- Wikipedia

- Home Assistant

- OBS

- Linux

- VLC

- DaVinci Resolve is rising soooo fast for video editing, and for good reason. Once you move out of the consumer/hobbyist tier or beyond Premiere and more into pro-tier hardware Resolve is fucking incredible. It will be a couple of years before it displaces Avid's strangle hold on the film industry, but it's going to happen.

- Blender

encoders, while you may not notice it, a ton of the media we consume is coded with open source, from:

- AV1 of Netflix/Amazon/Youtube fame

- VP9

- x264

- x265

- Apple Lossless, etc...

- ffmpeg

- Android is built off AOSP.

- Wordpress

And obviously I'm missing thousands of used-in-production very "succesful" projects.

GitLab is definitely the most obvious success at $600M+ in revenue, but a couple new ones are Cal.com and PostHog.

Cal.com is open-source Calendly, has raised $32M, and shares their stats publicly: https://cal.com/open

PostHog is open-source Mixpanel/Amplitude, has raised $39M, and appears to be widely recommended these days.

DokuWiki.

This database-free FOSS wiki engine [1] with a focus on simplicity is 19 years old, still gets updated, has useful plugins [2] for additional features, is a great choice for many uses, has adopters that use and love it, and has an estimated 50,000-250,000 installations [3].

As someone wrote, "DokuWiki is and will remain king for many simple reasons" [4].

  [1] https://www.dokuwiki.org
  [2] https://www.dokuwiki.org/plugins
  [3] https://www.dokuwiki.org/faq:installcount
  [4] https://old.reddit.com/r/sysadmin/comments/145l121/what_wiki_do_you_recommend/jnmd2t7/

OBS (Open Broadcaster Software) has largely become the standard over its (usually proprietary) competition.

I could list out a bunch of examples (and deleted my first draft of this comment listing various examples: Wikipedia, operating systems, Web browsers, software languages, databases, and a host of desktop and mobile apps generally).

But I think the more interesting perspective is to reverse the question: where are proprietary software specifically successful?

Many years ago I'd noted that the concept of a shrinkwrap-based software company had very few successful exemplars. Microsoft and, perhaps Adobe, being the best-known cases. Through the mid-aughts, most other "software" firms had tremendous consulting arms: IBM, Oracle, Peoplesoft, SAP, Symantec, Informix, and the Big-N consulting companies notably.

Since the mid-aughts, SAAS and social media companies have arisen, though that's still a segment where a very small number of companies come to claim a monopoly position, largely due to adtech dynamics (on both ad sales aggregation and surveillance data).

Actual shrinkwrap software markets are increasingly marginal, fighting for table scraps, with the remaining large participants (Microsoft, Adobe) increasingly headed to subscription and/or ad-supported business models.

gcc comes to mind. Remember when every computer came with its own C compiler? LaTeX also killed proprietary mathematics typesetting.

Examples I haven't seen mentioned yet:

Firefox. Atom/VSCode (Sublime Text clones). Android (iOS clone).

Various databases (postgres, mongodb, etc).

Reddit (Digg alternative, since closed source) though I'm not sure releasing their source code had anything to do with their success.

HashiCorp in general sort of counts though it's harder to say "it was competing against X".

Canvas is an open-source learning management system used at universities: https://github.com/instructure/canvas-lms

I think Blender applies - it's risen from the ashes and is used in commercial productions a lot in recent memory.

I like Bitwarden [0]. Backend in .NET.

[0] https://github.com/bitwarden/server

A "SaaS app" is something rather new. In the old times (early 2000s), you would buy some proprietary server code and get a consultant to install/maintain it for you.

I think vBulletin still operates on this model, although they now offer it as a service too. phpBB is the oldest alternative to vBulletin, there are plenty.

Eventually all these CMSs from the 2000s were cloned and freed in some way or another. Our "SaaS" was cpanel which automagically installed these (they were THIS close to "serverless", if they only knew). By 2010, people barely knew what MovableType was.

cpanel is gone, shared hosting is gone, but that cloned freed CMS tech evolved and still powers a large chunk of the web.

Why doesn't it happen now? I don't know. Maybe it takes time, maybe that was a lucky decade, maybe it's happening in some place I'm not looking at.

Wordpress is quite a big one?

I think Blogger was the main alternative back then, but there were probably several commercial ones with reasonable market share.

GitLab, Mattermost, RocketChat would be a few good examples of products that began as OSS alternatives to well-established players.

Outline (https://www.getoutline.com) is successful on most metrics you'd judge a business and OSS project on.

I'm not sure if any of these ever pitched themselves explicitly that way on HN though. I think explicitly labeling as an "Open source alternative" brings a lot of baggage and expectations, and often says more about the maintainers philosophical POV than ability to create a sustainable business ;)

For photo editing and manipulation 1) https://www.gimp.org/

2) https://www.digikam.org/

3) https://www.darktable.org/

Vector based editing tool

1) https://inkscape.org/

Desktop publishing

https://www.scribus.net/

Wikipedia - I remember when Encarta was how you used an encyclopaedia on your computer.

Blender.

Pretty much anything on the CNCF landscape. Tradeoffs are generally the same as always: trading control and effort for time and money. If you cannot make that tradeoff (i.e. because you cannot handle the control and effort or because you don't have the time or money) the choice is made for you.

Of course there can be a USP and quality aspect, take basic resource metrics for example, you can pay someone to do that for you, or you can do it yourself, the difference in effort is marginal but the difference in cost can be extreme. But there are cases where that marginal difference in effort is what tips the choice towards paying someone else to do it. In my experience, if you cannot make such efforts, or don't have a plan to make such efforts in the future, you're either in the wrong business or are doomed to fail purely on PnL.

cURL is ubiquitous. It's unclear whether there is even a proprietary alternative still being sold commercially.

We should also note, that all modern SaaS is running on mostly open source databases, open source languages, open source middleware, and the PaaS and IaaS they are running on are all powered by open source too.

This is not to disregard the meaningful thought and work that goes into the proprietary layers built on top of the open source codebases. But, we should all acknowledge that without those extremely high quality open source codebases, most SaaS wouldn't exist in the first place.

Good question, and I don't like the answers of other users. They are exclusively naming big well estabilished applications, that could be there due to pure luck.

Though it is true that LibreOffice, ffmpeg, and Linux are successful and widely used, I was much more curious whether the small ShowHN ones got anywhere. And I barely found any.

All (recent) FOSS success stories come from the proprietary apps being so screwed up. (At least that's my impression)

R language was created as an open-source clone of a proprietary language, S.

R or the Python Scientific stack over SAS or SPSS.

I'll narrow the scope to "OSS software that is common and where its license is not a selling point to most of its users." KHTML/Chromium/WebKit (to Internet Explorer), Firefox, MySQL, BSD (to AT&T Unix), GCC, LLVM, GIMP, InkScape, VLC to name a few.

Reports from large bodies of users is they are very happy with https://OnlyOffice.com which some clients are on to avoid GSuite to avoid sharing their business data with a faceless and highly ideologically partisan third party (Google).

Thus far the only cases where the MS Office users don't gradually slide into the gravity of an OnlyOffice service on private silicon is the heavy MS Excel (desktop) users who are of a very relevant (CFO, accounting) yet relatively small cohort.

I suppose I'm stretching the definition of SaaS here, but I'm going to say SSH (both client and daemon).

It was originally released as freeware, but after it was widely adopted in the mid 1990s, its creator made it proprietary and created a company called SSH Communications Security to sell it. After a series of security vulnerabilities in that commercial software, OpenBSD developers got fed up and created OpenSSH, and basically everyone migrated to that within a year.

Inkscape, Audacity, and ffmpeg. I know professional designers don't like Inkscape for UI and path limitations but I have gotten used to it and can use it effectively.

Odoo (formerly OpenERP) is a successful open source ERP.

Insomnia, open-source alternative to Postman for example make HTTP Request like the extension Thunder in VSCode.

I use Insomnia every day.

GCC, clang, Rust, most compilers these days. Nobody really uses a closed-source compiler now unless you are stuck with Microsoft.

Javascript is a funny one.

Javascript being an open standard meant there were no barriers to re-implementing them on alternative browsers. So when Internet Explorer started to lose its throne to Chrome and Firefox, Javascript survived while VBScript did not. When Apple decided to introduce webkit but not Flash to iOS, Javascript survived while Flash did not.

Both WireGuard and OpenVPN

Do you mean succeeded as in "has a large user base" or as in "makes a lot of money"?

Apache, Nginx, Caddy.

Audacity

KiCad.

Godot is inflecting fast as an alternative to Unity and has produced some hits on Steam such as Balatro and Cruelty Squad

Supabase

https://news.ycombinator.com/item?id=23319901

VLC comes to mind. It's been years since I last saw anyone using any other media player.

llama3 seems quite popular. not exactly a business by itself, but def a strategic play by meta.

It looks like baserow (open source alternative to AirTable) is making a fair amount of income.

To be fair, the vast majority of new businesses and projects fail, OSS or not.

Thunderbird

Kicad for electronic circuit design. Freecad for CAD and solid design.

Nextcloud and Bitwarden come to mind.

Blender, ffmpeg, pdf24

Minio - open source S3

Goatcounter

Blender

Asterisk

strapi (CMS)

A certain (free) operating system (just a hobby, won't be big and professional like gnu) for 386(486) AT clones.

Krita

Home Assistant.