There is a new wave of software coming, the single user application (SUA). AI makes it easy to write apps, and as a consequence, costs for writing software is going down massively and developing software is becoming cheap. What was not possible in the past, because it was too expensive, is now possible. We can write apps for a single user.
I wrote several single user apps over the last months, with the single user being me. Whenever I say “I wrote” I mean “Claude Code” wrote the code - and I managed the AI (architecture, testing, components, maintainable code, code reuse, …). To make this possible, you need to do it the right way - and it helps that I’ve been writing code for ~45 years (don’t create a SPA - 90% of use cases don’t need one!).
What single user apps did I write you may ask?
I wrote a blog app for my website, which is generated using Hugo. While Hugo creates the site, I use a “blogcli” app now to manage blog entries, see which ones are already on Linkedin, create SEO friendly descriptions and more.
I wrote an app to manage the CDN I use. There is an unofficial app, but it’s bad and lacks features. So my “bunnycli” manages redirects, domains, uploads, syncs faster etc. for my own websites (like https://www.amazingcto.com ).
I wrote an app for my CTO newsletter. The app downloads the bookmarks I collected over the week from Raindrop, creates a file in my newsletter file format which I then edit and add my opinions and then creates a final Markdown file for Hugo which I can upload to my email provider. An application 100% tailored to my workflow.
The biggest single user application yet: I’m writing a 35.000 LOC Go web application for managing my coaching clients. I was triggered to write this by a big influx of new clients, and my CTO coaching operations and client management became slower and slower and ever more painful.
The application I wrote is much better than the one I was using, because the creators of that app do not care nor do they even know about my jobs that I need to get done. But also, my app caters to an audience of one not an audience of millions. It’s perfect for my use case of CTO Coaching, making my life much easier and smoother. I dread admin work, like writing down session times and discussed topics for my clients, creating and sending invoices - for companies on one hand and CTOs who pay by themself on the other, inside the EU and outside of the EU (different invoices), companies in Germany, in the EU, and outside of the EU (different invoices to remember), different payment processors (IBAN, Wise, …) for different parts of the world (Africa, South America, US) and different tax requirements.
With my own app, all those pain points have gone away, and it’s smooth sailing. Agreed, no one else might have the exact same requirements, and the invoicing company I was using needed to think about all their clients - but should I care? I only care about my use cases.
If those use cases work, the app is feature complete! Too many apps today are in search for new users and new markets - they add more and more features, they start as something you want but end as something that you don’t need. Redesigns, rework, learning all the time, lost muscle memory. Ever rising prices for things you don’t need or want.
On top of that, with your own app, you own the data. You own your customers. When I asked my current time tracking and invoice provider if I could export some data, they told me that wasn’t possible. Huh?
This might not be for everyone, but the time investment pays off for me as a CTO coach with my”margins”. Would it be better to buy something that perfectly fits my use cases? Yes. Does this mythical unicorn exist? No, see above (also most coaching applications focus on getting new clients, not on making ops smooth and automated).
Why now and not before? Before AI, single user applications were a maintenance nightmare. A bug happens, I need to spend hours understanding the code I wrote months ago. Framework and library updates? Pain. Framework updates with Claude Code? Easy. Bug fixing with AI? Easy too (ALWAYS use plan mode, iterate on the plan, not the prompt). Claude Code reads the code and presents me the requirements in the code. It reads the code and fixes the bug. I no longer need to come back to 12 months old code I wrote and despair.
Over time there are also some significant cost savings. No subscription costs - in the era of everything going subscription, and you no longer can buy applications, this is a huge reduction in costs over time. A friend recently told me he has $1000/month subscription costs (including AI). I still need to work some hours to get that money back. Hosting is cheap too. If your application needs hosting, costs are low, because there is only one user. It’s $5-$10/month for running several of those apps in the cloud.
Is this for everyone? No. For now you need to know what you do.
Barriers will fall though and things will become easier for more and more people.
Soon there will be millions of single user apps (SUA).