# EverySingleCent

> Calculator-first expense tracker with multi-currency support for digital nomads, expats, and frequent travelers.

For the full documentation, see: https://everysinglecent.com/llms-full.txt

## Overview

EverySingleCent is a progressive web app that replaces traditional expense tracking with a calculator interface. Users open the app, type a number, and submit — logging an expense in under 5 seconds. No menus, no forms, no bank connections.

## Key Facts

- **Type:** Progressive Web App (PWA) — works on any device with a browser
- **Interface:** Calculator-first — the calculator IS the expense entry form
- **Entry speed:** Under 5 seconds per transaction
- **Languages:** English, Korean (한국어), Thai (ภาษาไทย)
- **Company:** EverySingleCent
- **Website:** https://everysinglecent.com
- **App:** https://app.everysinglecent.com
- **Status:** Pre-launch beta (waitlist open at everysinglecent.com)

## Currency Support

- **Fiat:** Any ISO 4217 3-letter currency code (USD, EUR, GBP, KRW, THB, ZAR, JPY, and 150+ more) with live exchange rates from exchangerate-api.com
- **Crypto:** 20 cryptocurrencies (BTC, ETH, etc.) with live rates from CoinGecko
- **Custom:** Unlimited user-defined currencies with manual exchange rates
- **Conversion:** All amounts auto-convert to user's home currency in real time. Original currency and amount are preserved alongside the conversion.

## Pricing

| Tier | Price | Features |
|------|-------|----------|
| Free | $0/month | Calculator-first entry, single currency, CSV exports, 3 categories, basic budgets |
| Pro | $4.99/month | Multi-currency with live rates, receipt capture with PDF scanning, tax deductible flagging, professional exports (Excel, PDF, JSON), unlimited categories and tags, per-category budgets, recurring transactions, data backup |
| Pro+ | $9.99/month | Everything in Pro, plus double-entry bookkeeping, account management, hledger-compatible journal export |

## Target Users

1. **Digital nomads** — Track expenses across multiple countries and currencies. Tag trips by destination. Under 5 seconds per entry.
2. **Expat professionals** — Manage dual-currency households. Flag tax-deductible expenses. Generate PDF reports for cross-border tax filing.
3. **Business travelers** — Log receipts in foreign currencies. Tag by client. Export PDF reports with bundled receipt images for reimbursement.
4. **Freelancers** — Track income and expenses separately. Set per-category budgets. Export filtered reports per client for invoicing.
5. **Weekend bookkeepers** — Full desktop keyboard and numpad support. Double-Enter workflow (calculate then submit). Batch a week of receipts in minutes.

## Features

### Core
- Calculator-first expense entry (arithmetic expressions: +, −, ×, ÷, %)
- Expense and income mode switching
- Customizable color-coded categories and tags
- Date selection and notes per entry
- Transaction search with filters (date, category, tag, currency, tax status)
- Timeline and compact transaction views

### Currency
- Favorite currencies for quick switching
- Live exchange rate fetching with 1-hour cache
- Fallback rate cache for offline use
- Currency conversion indicator on calculator display
- Original amount and currency preserved per transaction

### Exports
- CSV (compatible with any spreadsheet)
- Excel workbooks with formatted tables and breakdowns
- PDF reports (print-ready, filtered by date/category/tag/tax status)
- JSON backup (complete machine-readable archive)
- Receipt images bundled in ZIP alongside reports

### Budgets & Recurring
- Per-category budgets: weekly, monthly, or yearly periods
- Visual budget progress bars
- Recurring transaction rules with flexible scheduling
- Auto-generation of recurring entries

### Receipts
- Camera capture with multi-page scanning
- Scanner filter for image clarity
- Automatic PDF generation from scanned pages
- Receipt images linked to transactions
- Bulk download as ZIP

### Privacy & Security
- No bank connections — manual entry by design
- Row-level security (RLS) on all database tables
- No data selling, no third-party financial analytics
- Full data export at any time (JSON, CSV, Excel, PDF)
- Account deletion removes all data permanently — no shadow copies
- Security headers: HSTS, CSP (nonce-based), X-Frame-Options, nosniff
- Rate limiting on all public API endpoints

### Accessibility
- Full desktop keyboard support with numpad entry
- Double-Enter workflow: first Enter calculates, second Enter submits
- Dark mode with neumorphic soft UI
- Responsive design for mobile, tablet, and desktop
- PWA installable on iOS and Android home screens

## Technical Stack

- **Frontend:** Next.js (React), TypeScript, Tailwind CSS
- **Backend:** Next.js API routes, Supabase (PostgreSQL + Auth + Storage)
- **Hosting:** Vercel (auto-deploys from main branch)
- **Exchange rates:** exchangerate-api.com (fiat), CoinGecko (crypto)
- **Security:** Supabase RLS, nonce-based CSP, Upstash rate limiting

## Comparison to Alternatives

| Feature | Traditional Apps | EverySingleCent |
|---------|-----------------|-----------------|
| Entry method | Navigate → Add → Fill form → Save | Open → Calculate → Submit |
| Entry speed | 30-60 seconds | Under 5 seconds |
| Bank connection | Required (one country) | None (manual, by design) |
| Currencies | 1-2 currencies | Any ISO 4217 + crypto + custom |
| Exports | CSV only | CSV, Excel, PDF, JSON + receipt ZIP |
| Privacy | Bank credentials stored | No credentials, RLS, full deletion |

## Contact

- Website: https://everysinglecent.com
- Waitlist: https://everysinglecent.com/#waitlist