From Google Sheets to FinSimLab
When I started my investment journey, I didn’t want to hand over my finances to an insurance company whose advisor would push their high-fee products to me; I wanted to learn to manage my own finances. But knowing how to do that is not trivial, let alone in Ireland, where I live.
So I hired a flat-fee financial advisor who gave me sound advice and a view of my financial future with nice charts and data. When I saw the report I wanted to make all kinds of changes, experiment with a thousand different scenarios and see how they impacted the outcome, to answer questions like what if we delay the house purchase by a year, what if we lower expenses by 5%, what if we invest a bit more, what if there's higher inflation, what if..., what if..., what if...
Spreadsheet
The first thing I tried was Google Sheets. But spreadsheet formulas didn’t cut it, and since I had experience as a software developer, I used Google Sheets’ scripting language (javascript), to write a finance simulator engine. The spreadsheet provided the user-facing side.
I was able to run a lot of experiments with it. Learning what was possible made my meetings with my advisor more productive. I went in with a better understanding and some insights that I wanted to run by him.
I realised it was a valuable tool, so I shared it in the Irish personal finance subreddit and it was well received, but every time I made a change it forced users to make a new copy and re-enter their data, so I wanted to turn it into a website. I just had a stressful job and a family, and it never seemed the right time.
FinSim.ie
But then I lost my job, and by that time AI coding tools had arrived. So I switched from working for someone else to working for myself, at my own pace, and having a ton of fun trying the new coding tools. I used AI to help me create a website closely mimicking the spreadsheet, plugged in the code and the tax model that ran the spreadsheet, and published it as finsim.ie. Again I got a good response and valuable feedback.
Then I started considering the possibility of modelling other countries, which would open the door to experimenting with relocation scenarios and answer questions like what if I retire earlier and move to a country with lower taxes and cost of living? That would be valuable and open up the whole world. So I bought the finsimlab.com domain and got to work.
FinSimLab.com
It took quite a lot more time to develop than I would have predicted, and in the meantime the tools evolved a huge amount. I got to try a lot of different AI models and techniques, I learned what works and what doesn't, that lot of what I used as a profesional software engineer also applies here, plus there's a lot of new techniques that are necessary as well.
But I didn’t use AI just because I’m lazy, which I am, or easily drawn to the latest shiny toy, which I also am. I also used AI because it allowed me to scale in two dimensions: adding tax models for different countries, and translating the site into languages I don’t master.
What's next
And now that I got it to where I think it’s ready for prime time, my focus turns to marketing, which is definitely not my forte. I will not use AI in my communications with you, like this blog or answering to feedback. Genuine human contact is much more important to me than numbers.
Give it a try. I look forward to talking to you, hearing your feedback and helping you get value from this, my passion project.