Coinbud
A paired income and expense tracker installable as a PWA — one shared ledger for two people, with every entry attributed to whoever logged it.
Next JS
Supabase
Tailwind CSS
ShadCNCoinBud is a personal-finance Progressive Web App for manually tracking income and expenses, built around a core feature called Pair Link.
What It Is
- A manual income and expense tracker.
- Works great solo, but is designed for two people sharing one ledger.
- Every entry is clearly tagged to the person who logged it.
Why It Exists
Most budgeting tools assume a single user, even though money is often shared. Couples and partners end up with:
- Separate apps
- Separate totals
- Recurring disagreements about whose numbers are correct
CoinBud aims to remove that friction with one shared ledger, attributed entries, and no guesswork.
How It Was Built
Pair Link by Design
- Data model and sync layer are built around “shared by default, solo-friendly”.
- Two accounts see and edit the same ledger in real time.
- Every entry is attributed to the person who created it.
Calm, Trustworthy UI
- Visual tone is calm, restrained, and bank-like.
- No playful or gamified elements that might undermine trust.
Feels Like a Native App
- Mobile-first, installable PWA.
- Layout is capped to a phone-like width even on desktop.
- Feels like a dedicated app everywhere, not just a website.
What Makes It Unique
- Shared by Design: Pair Link isn’t a hack or add-on; it’s the foundation of the app.
- Calm Over Gamified: No streaks, badges, or mascots, just a clear, steady space for two people to manage money together.
- Real-Time Sync: Changes appear instantly for both people, so no one is working with stale numbers.
Key Takeaway
Building CoinBud showed that good shared tools can’t just be solo tools with a “share” button. They need to be designed around the relationship from the start. Thinking of two users as one unit, from the data model up, now shapes how collaborative features are approached in every future project.