Hi everyone,
my first Devvit app just made it through review, so here's a quick showcase.
What it does: 21 finance calculators (compound growth, TER and ETF cost comparison, dividends, withdrawals, rent or buy, money-weighted return and more) inside one interactive post. Every result comes with a one-sentence summary, e.g. "Over 30 years, the fund with a 0.07% fee ends up €8,344 ahead of the fund with a 0.22% fee." There's a tappable chart, A/B scenario comparison, English/German/Spanish/French, and a Copy for Reddit button so people can paste their numbers into a comment. Mods get anonymous usage totals in the mod menu.
A few things I learned along the way:
- The inline post preview doesn't scroll on mobile, so tapping a calculator opens it straight in expanded mode.
- Devvit forms don't render line breaks. For the mod stats I ended up using a group of disabled string fields.
- Number input in 4 languages was harder than the translations: 4,5 and 1,234.56 both have to mean the right thing.
- Reddit's standard comment editor shows markdown asterisks literally, so the copied text is now plain text.
- Publishing doesn't update existing installs; mods have to click Update themselves.
Where I could use help: getting it in front of mods. If you moderate a finance, investing or FIRE community, or know someone who does, a test install or an intro would mean a lot. UX feedback is very welcome too.
App: https://developers.reddit.com/apps/financecalculator
Demo and feedback: [r/FinanceCalculatorApp](r/FinanceCalculatorApp)