Origin Story
How FinSimLab came to be, and how it's built.
FinSimLab started its life as a Google Sheet. I live in Ireland, so I wanted to model the Irish tax system to answer questions like:
- Is it better to invest in a low fee but high exit tax ETF or in a lower tax but high fees Investment Trust?
- What if I delay the house purchase by 5 years?
- Can my plan survive higher inflation or a market crash?
Spreadsheet formulas didn’t cut it, and since I had a couple of decades of experience as a software developer, I wrote the simulator in Javascript (this was before ChatGPT). The spreadsheet provided the front-end with input fields and nice charts. I shared it in the Irish personal finance subreddit and got quite a lot of interest. I always thought about making it into a website, but I had a stressful job and a family, and it never seemed the right time.
Then two things happened: I lost my job, and AI coding tools 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 tax rules that ran the spreadsheet, and published it as finsim.ie, free to use and for Ireland only.
Then I started considering the possibility of modeling 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 the market to the whole world. So I bought finsimlab.com and got to work.