What started this project?

This web application was born out of a desire to better understand how different strategies and choices around personal finance affect it in the long term. Additionally, I wanted to experiment with d3 by Observable, a powerful data visualization library for JavaScript.

The problem

I started my professional career as a developer in 2022, and since then, I have been saving money in various ways. I own an apartment and a car, both financed by loans. Additionally, I have a student loan and some insurance policies. Occasionally, I receive non-recurring income, such as bonuses or dividends from stocks. My goal is to ensure that the money I save today, and the financial decisions I make, are aligned with long-term stability and growth. Most importantly, I want a straightforward solution that simplifies these decisions, so I don't have to rely on my old and dusty Excel sheet every time something new comes up.

The solution

I started out with an Excel sheet that quickly turned quite complicated and hard to modify whenever something new came up. Had I spent half the time I have on this project just finishing that sheet, I probably would have been a rich man already, but a true developer is someone who spends 4 months automating something that could have been done manually in a day.

Whenever I mentioned this sheet to others however, they expressed interest in having something similar. Why not create something that I can also blog about?¹

I want to start out simple: A one-pager that lets users fill out some basic information about their financial situation and present them with an interactive graph that shows forecasted yields. The form-section of the site lets them add zero to many components that each play their role on their financial horizon. The visualization will take various financial factors into account like taxes, different tax relief mechanisms perhaps most importantly, compunded interest.

Mobile first (?)

Before diving headfirst into a mobile-first approach, it’s worth considering how the context of using this product differs between mobile and desktop, and what unique challenges mobile users might face that desktop users do not. Here are some issues I identified early on that need to be considered for mobile users:

• Mobile users have a more limited experience accessing the necessary information about their finances. For instance, retrieving detailed information about loans, funds, and transactions is more challenging when navigating through different apps and websites.
• Tables of data are very difficult to display effectively on mobile devices.
• Information-rich time series data visualizations are hard to get right on devices with limited screen width.
• UI elements in mobile apps often differ somewhat in design from typical web interfaces. The product should feel familiar by adhering to design principles commonly experienced on mobile.

Being mobile-friendly is however helpful for gathering interest and showcasing the product as most interactions with others rarely happen in front of a computer.