How I earn a living selling my open source software


I'm the founder and sole developer of my own open source software called open3A. It's a web-based invoicing application that I started in 2007 and have developed ever since.

I initially developed open3A because I needed it myself to write invoices to my customers. When it was working I just put it out there in the internet because I thought someone else might find it useful. It was one of the first (maybe the first, idk) web-based solutions in this area after all.

In fact someone found it useful and asked if I could add some features. I was still in the university and did it for free because I didn't think much of it. After a while he wanted to pay me money for my work and why should I have declined? 😉

Then others came and asked for more features which I implemented. Sometimes payed, sometimes free.

After a while doing this I had collected quite a bit of functionality and thought about how I could sell open3A as a product and not only my time developing it. But I didn't want to sacrifice what I believe in:

  • open source
  • No licensing keys or dongles
  • No subscription
  • No time or other limits in no version, not even the free one
  • No other stuff that annoys me with other software

In short: I wanted to make software like I wanted software to be. After 14 years I still do it this way and my business is better than ever 😃

What have I done?

I have a demo version directly on my homepage where anyone can try open3A without login or setup. It's reset once a day. It is my primary mode of sale. I let the product speak for itself.

I have a free version of open3A which is as useful as possible without any limits but of course it is missing advanced functionality. This version gets full support by me via phone and email. This is my bait I put out there and I'm sure there are hundreds of people who use it this way and it's fine for them.

If someone wants advanced features, I have a shop! 🎁

In my shop the users can buy many of the extensions I have developed over the years. The prices are reasonable and start at 20€ (~$24) up to around 80€ (~$96) or so. The price contains updates for this extension for one year which means the next two versions.

Here comes the crucial part: My shop remembers all the extensions a customer bought and every time she downloads her version it puts all the paid for extensions together in a zip file for the update. This is how I sell open source. The customer gets the code (and functionality) after she bought it.

In 2013 I added a cloud service where open3A can be rented from me and I take care of all the technical things like backup and updates. This is great for steady income.

In 2018 (I think) I also added a subscription model after several customers asked me for it. Which means they can always download the most current version and get a discount. In return I get steady income.

In 2021 I recently launched my newest product: It's called open3ABox and it's a raspberry pi with open3A pre-installed which I deliver to my customers who have not the technical skills for their own server but don't want a cloud version either. It's fully remote managed and monitored by me ➡️ more steady income, yay 🎉

Aside from the technical part I sell open3A through really good support. I think this is a very important part for keeping the customers I already have.

In this post I have focused on the things that worked. But I have literally sunk hundreds of hours and thousands of euros along the way for things that didn't work. I tried to sell open3A on a CD in 2010 and sold exactly one copy. I had someone program an installer and never used it. I built several websites for sub-applications of open3A until I realized it was way too complicated. I tried to spin off a new application called office3A and dumped the idea after a lot of work. I had multiple projects with business partners which sounded like a great idea but never sold. Selling software B2B is the second hardest part I am doing in my life. Right after keeping my sanity through the craziness that is life.

I'll have my first part-time employee starting April 1st and probably next year I can have two full weeks of uninterrupted holidays. I can't even remember the last time I've done that. It's been a really long road but I wouldn't want to miss a piece of it. It made me the the confident woman I am today because I made it work with my own hands. I did all of it and I'm so damn proud.

Thank you, life, for continuing to teach me the lessons I need to learn.

  1. 4

    Thank you for sharing your remarkable journey, @nemiah! So many inspiring useful gems to learn from you. I love that you use an online demo to let your product, "speak for itself." Congrats on your first employee, too. Enjoy your well deserved upcoming vacation. Best wishes!

    1. 2

      Thank you for your kind words 😌

  2. 3

    One of the best pieces on open source that I’ve read in the past 5 years! We need more of these indie open source success stories out in the open. Would love to chat at some further length about this topic.

    1. 3

      Thank you, that's nice of you to say.

      I'm thinking about how we could chat, but I'm not on any of the usual platforms. I'm complicated that way 😊 I guess you'll have to write me an email: support 🌀 open3a.de

      1. 1

        Thanks! Email sent :)

  3. 2

    Great writeup, thanks for sharing.

    I’m curious how you are able to charge for plugins. Are the plugins open source too?

    1. 2

      Thank you for your question!

      Yes, the plugins are open source, too. Customers can test what they will get in an online demo which is available on my website.
      They get the functionality as well as the code after they bought the extension in my shop.

  4. 2

    thank you for sharing, found this post at rigth time.

    1. 1

      Thank you for your comment!

  5. 1

    This is awesome! Great post, great story!

  6. 1

    Very inspiring @nemiah! Love the opeb3ABox idea - it would be interesting to get an update on that later this year to see how that's gone.

    1. 2

      I am somewhat further in the process.
      I developed an open source library, I created a business model for it, and I grew the business from 0 to 10M euro revenue. Eventually, I made an 8-figure exit.
      I recently wrote down the whole experience. My book will be released next month: https://entreprenerd.lowagie.com

    2. 2

      Nice idea, but I usually don't expect much. 5 boxes in 2021 would be great. I've put it in my calendar for December ;)

  7. 1

    Thanks for sharing this post, Nemiah!

    1. 1

      You're welcome! I didn't quite anticipate the huge amount of interest though 😲 Usually the internet is a huge void 😊

  8. 1

    What a great story. I like how you focus on the product and let the features speak for themself.

  9. 1

    Thanks for such an inspiring story 🤗

  10. 1

    Woah! Power-packed story without a doubt. Thank you so much for sharing this and inspiring me

  11. 1

    Inspiring story. I'm curious about the growth of your business. It sounds like this is your sole or primary source of income? How long did it take until you felt comfortable living off the income open3A generated?

    Also what was your strategy for marketing early on? In another comment you mention that you don't do much active marketing, I take it most of your customers come from word of mouth? How did you go about securing your first customers?

    1. 6

      Thank you for your question!

      Yes, open3A is my primary source of income. I do side projects though, if they sound fun and earn a monthly income. I always put more than one teapot on the fire. You never know. But I got more picky of my side projects over the years 😉
      I'd say it was about ten years in, when I started to shift my business towards more open3A. But I never had a grand plan to live off open3A in the first place. I suppose that is different for someone who has an idea and wants to build a business on it. But having a business has taught me many times over to be humble, grateful and to go with what works.

      In the early days there was no Twitter or Insta or FB. In fact I decided against using it recently because open3A is B2B and it's hard to reach businesses over these channels. I did SEO in the beginning and was first place for a few years when there was fewer competition. Today I don't see a chance for me to make an impact on Google search results with huge companies throwing money around. I also did press releases when a new version was out, but my partner wrote them and when she was too busy working, we stopped. My page hits did reflect that though. I also uploaded open3A to download portals, they were also a thing back then 😆

      Yes, most of my customers these days come from word of mouth. Those are my best customers because someone else has done the convincing and takes support off my shoulders. This is why I'm planning a partner program for the ones who "sell" open3A.

      Well, you know, I had project work so I never was under pressure to have open3A customers. But I'd say securing a customer for me is a mixture of "It's alright, I don't need you" (I even told that to the biggest customer I have to date 😁), listening to them, only selling them what they need (I would be grateful for that myself, sometimes I even say to them that another software might be better suited for them) and delivering constant value by taking care of the problems that arise with my software (bugs, new use cases,…). People are so happy when I take care of the problems they have. A new customer is often a lot of upfront-work with insecure outcome. This is the way.

  12. 1

    Thanks for sharing!

  13. 1

    Thanks for sharing, this is inspiring indeed. Quick question: by open source you mean freeware ? Because open source means that your code is available to the public.

    1. 2

      Well, no, open3A is no freeware. I know it usually is seen as if open source was the same as freeware. But open3A is "only" open source. Which means anyone who runs the software is allowed to see the source code and make alterations to it like she pleases. Some people actually do that with open3A, too.

      In theory they are also allowed to re-sell the software. But we all know how hard it is to run a company and sell something. This hasn't been an issue so far.

      Freeware does not mean you get the code. It just means the software is for free.

      This is why I built my shop the way I did. The customer can preview what she will be buying in the online demo and gets access to the program as well as the source code after she paid me for it. 😈

      1. 2

        I see. Well to answer your question about "How I earn a living selling my open source software", I think one common practice in open source is to adopt a plugin kind of model. Your software is free, but you can have a plugins system to allow users to perform this or that functionality or to integrate with other systems. You can provide official plugins but also allow users to develop their own ones. Accordingly, you can develop a market place that allows the share / sale of plugins , and require users to pay to share their plugins in the marketplace or take commissions on plugin sales.

        1. 2

          Yes, this is the way I do it. Minus the marketplace. But it sounds like a good idea 🤔

  14. 1

    Great post!
    I have questions
    1 . What is your marketing channels?
    2. And why you are focusing only in the German market?
    3. what is more profitable ? the could version or the on-prem version

    1. 3

      Thank you!

      1. Fun question, because the answer is: I have my homepage and my existing customers. I don't do active marketing. No Instagram, no Twitter, no Facebook, no younameit. Of course I have collected probably some backlinks over the years and I also did SEO in the beginning, when there was fewer competition and Google less annoying. We're planning to start a partner program this or next month to say thank you to my loyal customers who promote open3A for free.

      2. The German market would be Germany, Switzerland and Austria. That's over a hundred million people. Works for me 😉

      3. I have no exact statistics but I'd say it's about 40% cloud and 60% who install it themselves.

  15. 1

    The open3ABox idea is amazing!!!

    1. 2

      We'll find out 😁 I pitched it to four people and sold one so far.

      I'm actually thinking of offering the system as a platform for others to put their applications on. Would be fun, I guess.

      That gets me thinking. Is anyone here willing to work with me on that? Maybe I'll make another post…

      1. 1

        If you have some free time, doesn't hurt to try turning it into a platform! I think there are some potentials in that idea if the data handled by the software are super sensitive for the tenants to put in the public cloud.

        Like in some countries, companies keep two "books", one for public, and the other... you know what I mean. ;)

        1. 1

          I've seen several companies offering on-premise-versions of cloud products, i don't know yet. It's a lot of work to make an actual product with all the cases considered.

          Hehe, yes, that is one possibility 😉

  16. 1

    You should be proud of what you've achieved, especially since starting 14 years ago. Not many can last that long :)

    I like your strategy -- let the product speak for itself and also providing really good support. That's exactly what I'm doing for my business as well.

    And lastly, congrats on your achievements!

    1. 3

      Yes, not many last that long, but I didn't have a fixed goal where I wanted to be, either.

      open3A wasn't planned. It just happened and I went along with it. I founded my first company because I was good with computers and work always found me.

      I earned money with other projects until a few years ago when I decided to focus my work on open3A. I still do side projects if they sound fun and earn a monthly income.

      I guess it would have been so much harder if I had tried to force success for only one idea. Instead I practically swam where the current did take me. There are a few examples of companies out there where it worked that way.

      Thank you, I wish you all the best for your business and your life!

  17. 1

    Your experience will definitely benefit a lot of folks around here. Appreciate you sharing your journey with us. ~14 years of hustle is no easy task, I aspire to be this disciplined and focused :)

    All the best @nemiah

    1. 3

      Thank you!

      I personally can recommend meditation, it really helps me a lot with my business and my life. There have been many paths that didn't work out in both areas and most times I just had to recognize them for what they were and let them go.

      I'm sure you'll find your way, too!

  18. 1

    That's really awesome. You have what I consider to be a dream job. Write open-source software and get paid to do it!

    I don't think I'd offer phone support for non-paying users. It's already stressing me out and I'm not the one handing out my phone number.

    I'd be curious to know how you manage and monitor those boxes and the server.

    1. 2

      Well, yes, I know what you mean 😉 It's a dream and it is not at the same time 😁

      I didn't offer phone support for a very long time either. It's stressful, I agree. But I had an idea: I started publishing hotline times on my homepage. Two times a week. Currently on Thursdays and Fridays between 10 am and 11:45 am I take calls. If someone calls at another time I take the call if I am in the mood 🤠

      That is a story of it's own. I'll give you the gist: the boxes keep an open websocket connection to my server. Over this connection I do the monitoring and I can tell the box to forward it's ssh port to one of my servers to do the updates. I initially built this service for another purpose (which didn't work out) and re-used it for open3ABox.

  19. 1

    This is really cool! Great to see open source working for you, and love reading about how you monetized it!

    I tried to build an open source product a few years back (Brisa Boards - Yet Another Damn Task Management App haha). I thought open source would get extra eyes on it, and motivate me to keep developing it.

    Sadly, after a year or two, I got so little feedback that I gave up on the project. I think it shows that just because something is open source, doesn't mean people will use it. You still have to promote, make sure it's solving use cases, etc - all the things you have to do with normal apps.

    Really inspired to see the resurgence in open source, as well as IHers focusing on user needs and making money off of it.

    1. 4

      Thank you for your comment!

      I agree, open source by itself is a weak selling point. Most people can't program. I usually used it as a way out if someone asked me what happens if something happens to me. I'd just tell them "it's open source, you can get anyone to fix it for you." Haha, sure 😂

      Aside from that it's an application like any other, yes.

      I'd like to see more open source, too. But I guess people don't know how to monetize and with all the cloud stuff it doesn't matter anyway.

      1. 1


        A small fix or patch maybe..

        A new feature is most likely a completely different story and takes a considerable investment. Not that a non developer is expected to know that.

        Love your story, also tried making a living of open source and while it partly works, it was never successful enough for me to be able to live off that.

        Getting that alone to work is huge. On top of that you have a product with a lot of happy users from the sound of it.

        Also love the way you reason about how to do business and -yes- direct potential customers to another product if that's a better solution for them.
        I completely agree and also find myself to do the same thing at times.

        1. 1

          Yes, I know of very few people who actually implement bigger changes in my software. Usually they ask me first if I have time 😊

          Well, it took me a very long time and a huge amount of effort, especially in the beginning. The good thing is, now I can literally reap what I have sown a decade ago. Sounds crazy, especially in the software business, but this is my experience.

          It happens rarely that I propose another solution, the people know what they will get, before they call me. In my opinion It's the best outcome for everyone. What should I do with an unhappy customer getting on my nerves? 🤔 😉

      2. 1

        This comment was deleted a month ago.

  20. 0

    Just curious if I am misunderstanding. Initially you stated:

    But I didn't want to sacrifice what I believe in: No subscription

    But later you state:


    Did something change in your beliefs?

    1. 1

      You're not misunderstanding. I added the subscription model because customers actually asked me for it. open3A can still be used without subscription. If one cancels the subscription my software will still run as usual, I'll just cancel the updates.

      1. 1

        Thank you for replying!

  21. 0

    🎉Living the dream! Congrats on the first employee and on a successful product. Thank you for sharing.

    Are you planning on making your product available in English?

    1. 1

      Thank you, it's hard work to get her up to speed though 😅

      A lot of open3A is translated in English and Spanish because I have some customers there. But I have no intention of marketing it because I have no clue about the legal stuff in english-speaking countries.

  22. 0

    More grease to your elbows...

  23. 1

    This comment was deleted 22 days ago.

    1. 5

      I cried writing this part 🙄
      Thank you for saying it's inspiring because for me it's mostly humbling 😌

      Let me know when you are ready to share what your business is about.

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