Expense Tracker
Personal finance app for tracking spending, budgets, and category insights in real time.
Technical Challenge
Most budgeting apps bury the one thing that matters, where the money actually went, under cluttered dashboards and slow manual entry. Tracking spend across categories meant exporting CSVs and building spreadsheets by hand.
Engineering Solution
Built a fast, secure single-page app with instant transaction entry, custom categories, and live charts. A JWT-secured Express API aggregates spend server-side, while Recharts renders monthly trends and category breakdowns that update the moment a transaction lands.
Code Spotlight
"aggregateSpend.ts"
MongoDB aggregation that rolls every transaction up by category for a given month, returning a sorted, chart-ready series in a single round trip instead of pulling raw rows to the client.
export async function spendByCategory(userId: string, month: string) {
return Transaction.aggregate([
{ $match: { userId, month, type: 'expense' } },
{ $group: {
_id: '$category',
total: { $sum: '$amount' },
count: { $sum: 1 },
} },
{ $project: { category: '$_id', total: 1, count: 1, _id: 0 } },
{ $sort: { total: -1 } },
]);
}Technical Metrics
Dossier Context
Product Deep Dive?
I specialize in high-scale architectural builds. Let's discuss the mechanics of your next project.