Fast forward to now. I'm a Buffett nerd — big believer in compound interest as a mental model for life. I run compound interest calculations constantly. Not because I need to, but because watching numbers grow over 30-40 years keeps me patient when markets get wild. It's basically meditation for long-term investors.
The problem? Every compound interest calculator online is terrible. Ugly interfaces, ads covering half the screen, can't customize compounding frequency properly, no year-by-year breakdowns. I've tried so many. They all suck.
When vibe coding started blowing up, something clicked. Maybe I could actually build the calculators I wanted? I don't have to be a "real developer" anymore — I just need to describe what I want clearly.
So I tried it.
Two weeks and ~$100（Opus 4.5 thinking model） in API costs later: I somehow have 60+ calculators. Started with compound interest, naturally. Then thought "well, while I'm here..." and added mortgage, loan amortization, savings goals, retirement projections. Then it spiraled — BMI calculator, timezone converter, regex tester. Oops.
The AI (I'm using Claude via Windsurf) handled the grunt work beautifully. I'd describe exactly what I wanted — "compound interest calculator with monthly/quarterly/yearly options, year-by-year breakdown table, recurring contribution support" — and it delivered. With validation, nice components, even tests.
What I realized: my years away from coding weren't wasted. I still understood architecture, I still knew what good UX looked like, I still had domain expertise (financial math). I just couldn't type it all out efficiently. AI filled that gap perfectly.
Vibe coding didn't make me a 10x engineer. But it gave me permission to build again. Ideas I've had for years suddenly feel achievable. That's honestly the bigger win for me.
Stack: Next.js, React, TailwindCSS, shadcn/ui, four languages (EN/DE/FR/JA). The AI picked most of this when I said "modern and clean."
Site's live at https://calquio.com . The compound interest calculator is still my favorite page — finally exactly what I wanted.
Curious if others have similar stories. Anyone else come back to building after stepping away?
Now I build all sorts of apps for my farm and organizations I volunteer for. I can pound out an app for tracking sample locations for our forage associations soil sample truck, another for moisture monitoring, a fleet task/calendar/maintenance app in hours and iterate on them when I think of features.
And git was brand new when I left the industry, so I only started using it recently to any extent, and holy hell, is it ever awesome!
I'm finally able to build all the ideas I come up with when I'm sitting in a tractor and the GPS is steering.
Seriously exciting. I have a hard time getting enough sleep because I hammer away on new ideas I can't tear myself away from.
I'm teaching my kid what I consider the AI dev stack: AI IDE (Antigravity for us), database (Supabase for us with a nice MCP server), and deployment (Github and Vercel for us). You can make wonderful little integrated apps with this in hours.
Honestly, I have so many features in it now it's hard to describe it, shared work calendar, parts shopping list, recurring maintenance, blah blah blah. It's very bespoke and I doubt anyone else would want to use it the way we do.
Did you take over a farm?
The only thing Deere "locks down" is that some of the parts have a CANbus address that you need to get a tech over to program the controller to recognize the part, and do the same if you replace a controller.
It's not some nefarious anti-farmer thing, it's because of the way the controller network works. In fact, I've used a CANbus sniffer on the bus and everything on there is in the clear, they don't even encrypt the messages.
The only things I've sent to town to get fixed was because I didn't have time to diagnose it, or it was an insurance claim and I wanted warranty. Blowing $80,000 worth of innards out the back of a combine wasn't a job I wanted to tackle right then (but I probably should have, I wasn't happy with the attention to detail in the repair).
So the upshot is, don't believe every terrible story about Deere you hear. Just the one where they charge too goddamn much for parts.
Dead Comment
There is an incredible irony in your typing that out on a device so advanced that it was beyond science fiction when I was growing up 40 years ago.
If you look at Soviet or Chinese Communism, they also stifled innovation, and they also destroyed entire ecosystems. They also had extreme concentrations of power, which allowed psychopathic leaders to commit atrocities.
If we want to come up with real long-term solutions, maybe we need to be honest about underlying human traits, and address those via systematic controls. Otherwise, it feels like we are going to keep bouncing from extreme to extreme. That tendency towards extremes seems like another easily exploited human trait that needs to be identified and addressed.
I guess my point here is that maybe it's not entirely specific systems at fault here, as much as it is universal human traits and group dynamics.
Disclaimer: I thought we had already found the beginnings of an answer, and it was Social Democracy with a regulated market economy. However, this system appears not to be extreme enough for many people to get excited about it.
I'm not sure how you can claim this on the footer of every page when you're vibe coding these calculators.
How confident is the OP that every single one of these 60 calculators work all the time, with all edge cases? Because if someone is on your website using your calculator, they are putting trust in you. If it's wrong, it could have downstream impacts on them. I hope every single one has a comprehensive set of tests with good edge cases. But realistically will they?
I'm actually pretty pro-AI development. But if you're going to use AI to help develop a website, at least focus on quality rather than quantity. AI makes quantity easy, but quality is still hard.
As an aside, the website doesn't even work for me. My clicks don't don anything.
The compound interest calculator, which is their 'favorite page', already shows an incorrect value in the graph. So my faith in the other calculators isn't great. I also kinda doubt OP's story of them using that page all the time, since it took me about 20 seconds to find this issue.
The value isn’t the interface, it’s the trust that its calculations are accurate. I can’t tell you how many meetings I had with accountants and finance people to validate all the calculations.
Would you be asking the same question if it's written without AI? How can any software be always working will all edge cases?
In the end, my feeling is there needs to be transparency in how bulletproof-tested a product is. IMO even a calculator that might be wrong can be useful if it's the most convenient option and the user knows the risks (though to be clear, that is not the philosophy I am employing in my personal project).
- You all should build your own software. AI is so good!
- You all should use the software I built with AI. It's so good!
do you understand how bad it is when you search for software and you cannot trust it to do what you ask of it? it's bad!
AI is perfect for building those little tools for you and maybe your family, ones you have no intention of making unicorn startups, but help in your day to day.
You get a bespoke solution and don't need to worry about that free app you found moving to a subscription model when the author wants to profit off it or sells it to a VC company.
It doesn't have to be perfect code, secure or anything else. If it does what it should, it's good.
I’m not an AI hater but I do see this as evidence of LLMs being susceptible to chasing trends as much as people.
Next.js with server rendered React is not a stack that an experienced web developer would have recommended for a “clean” solution to a collection of financial calculators. It’s the answer you’d get if you asked for the stack that’s trending the most lately.
Do you speak with web developers on a daily basis? It seems to be the default stack for everyone to build from from a Saas to a TODO app for the last 5 years or so.
These are all quite reliable well-understood components, and far from "chasing trends" IMO.
Creating a polished, usable app is just so much work, and so much of it isn't fun at all (to me). There are a few key parts that are fun, but building an intuitive UI, logging, error handling, documentation, packaging, versioning, containerization, etc. is so tedious.
I'm bewildered when I read posts by the naysayers, because I'm sitting here building polished apps in a fraction of the time, and they work. At least much better than what I was able to build over a couple of weekends. They provide real value to me. And I'm still having fun building them.
I now vibe coded three apps, two of them web apps, in Rust, and I couldn't write a "Hello World" in Rust if you held a gun to my head. They look beautiful, are snappy, and it being Rust gives me a lot of confidence in its correctness (feel free to disagree here).
Of course I wouldn't vibe code in a serious production project, but I'd still use an AI agent, except I'd make sure I understand every line it puts out.
I believe you can use LLMs as advanced search and as a generator for boilerplate. People liking it easy are also being easy with quality attributes, so anyone should be self aware where they are on that spectrum.
Thanks.
Then don’t do it. No one is forcing you. Are you also going to complain that building airplanes and ensuring food safety are too much work and not fun for you? Not everything needs to be or should be dumbed down to appeal to lowest common denominator.
Alternatively, go work at a company where you’re part of a team and other people do what you do not enjoy.
> I'm sitting here building polished apps in a fraction of the time
No, no you are not, guaranteed. “Polishing” means caring about every detail to make it perfect. If you’re letting the LLM make most of it, by definition it’s not polished.
The airplane company wont let you vibe code their systems anyway, and rightly so. the rest of us can just do whatever we like.
No one is also keeping me from doing what I want to spend my time with on my days off.
> Are you also going to complain that building airplanes and ensuring food safety are too much work and not fun for you?
No, because this isn't remotely comparable to weekend hobby projects. What a weird question.
> No, no you are not, guaranteed. “Polishing” means caring about every detail to make it perfect. If you’re letting the LLM make most of it, by definition it’s not polished.
I guess we have different definitions of "polished" then.
thats why it was valuable.
All things worth doing are hard.
This is why we have compilers rather than writing assembly by hand.
The years "away" gave me an unusually clear picture of what problems actually need solving vs what's technically interesting to build. Most devs early in their careers build solutions looking for problems. Coming back after working in a specific domain, I had the opposite - years of watching people struggle with the same friction points, knowing exactly what the output needed to look like.
What I'd add to the "two camps" discussion below: I think there's a third camp that's been locked out until now. People who understand problems deeply but couldn't justify the time investment to become fluent enough to ship. Domain experts who'd be great product people if they could prototype. AI tools lower the floor enough that this group can participate again.
The $100 spent on Opus to build 60 calculators is genuinely good ROI compared to what that would have cost in dev hours, even for someone proficient. That's not about AI replacing developers - it's about unlocking latent capability in people who already understand the problem space.
Feel like forums have turned into a grand Turing Test.