Documentation

Learn how to use Zenkasu to organise your numismatic collection.

Getting Started

Zenkasu is a web-based collection manager that runs entirely in your browser. No signup, no backend, no data sent to servers. Everything is stored locally on your device.

First Steps

  1. Open the app in your browser
  2. Click the + Add button to add your first item
  3. Fill in the details and click Save
  4. Your collection appears instantly!
Tip: Bookmark the app page for quick access. All your data is saved automatically to localStorage.

Adding Items

Zenkasu supports structured fields organised into categories. The form adapts based on the item type you select — coins show physical properties and KM numbers, banknotes show serial numbers and printers, sets show coin count and completeness. Bullion is a coin Type (alongside Regular, Commemorative, and Pattern), not a separate category.

Core Information (all categories)

Category-specific fields

Grading (coins, banknotes)

Acquisition and value (all categories)

Tip: If you enter a denomination with a current currency and leave estimated value empty, the value is filled in automatically. Useful for circulating coins at face value.

Import & Export

Importing from CSV

  1. Click ⚙️ Settings dropdown in the toolbar
  2. Select Import CSV
  3. Choose your CSV file
  4. Select Append (add to existing) or Replace (delete all and import new data)
  5. Click Import to complete

CSV format should have headers matching field names:

name,category,year,country,grade,purchase_price,estimated_value
2€ Germany,COIN,2024,Germany,MS70,4.50,5.00
American Gold Eagle 1oz,COIN,2023,United States,,2100.00,2200.00

Exporting to CSV

  1. Click ⚙️ Settings dropdown in the toolbar
  2. Select Export CSV
  3. File downloads as zenkasu-collection-YYYY-MM-DD.csv
  4. Open in Excel, Google Sheets, or any CSV tool
Tip: Export regularly as backups. CSV files can be opened in any spreadsheet program.

View Modes

Cards View

Beautiful grid layout perfect for browsing your collection. Shows key details at a glance. Hover over cards (or tap on mobile) to reveal action icons in the bottom-right corner:

Table View

Spreadsheet-style view showing all enabled columns. Works like a spreadsheet for fast editing:

Tip: For bulk entry, add items via the modal, then switch to table view to quickly fix values by double-clicking cells. Much faster than reopening the modal for each item.

Switch between views using the view tabs: [Cards] [Table]

Column Configuration

Customise which fields appear in forms and table view:

  1. Click Settings dropdown in the toolbar
  2. Select Configure Columns
  3. Check/uncheck fields to show/hide them
  4. Fields are grouped by category: Core, Grading, Physical, Banknote, Set, Acquisition
  5. Click Reset to Defaults to restore original settings
  6. Click Done to save

Name and Category are mandatory and cannot be hidden. The add/edit form automatically shows only fields relevant to the selected category — selecting "Note" hides coin-specific fields like KM number, and shows banknote fields like serial number instead.

Your column preferences are saved automatically and apply to both the add/edit form and table view.

Favourites System

Speed up data entry by starring your most-used countries and currencies.

Managing Favourites

  1. Click Settings dropdown in the toolbar
  2. Select Manage Favourites
  3. Check countries and currencies you use often
  4. Click Done to save

Using Favourites

When you type in country or currency fields, your favourited items appear first in autocomplete with a ★ star icon. This makes data entry much faster.

Tip: Star 5-10 countries and currencies you use most. They'll always appear first for faster entry.

Dashboard Statistics

The dashboard shows customisable stats about your collection. Click any stat card to see detailed breakdowns.

Available Stats

Customising Dashboard

  1. Click Customise Dashboard button
  2. Check/uncheck stats to show/hide them
  3. Click the × on any stat card to quickly remove it
  4. Click Reset to Default to restore original stats

Frequently Asked Questions

Where is my data stored?

All data is stored in your browser's localStorage. Nothing is sent to any server. Your data stays completely private on your device.

Can I use this on multiple devices?

Each device stores its own data. To sync, export from one device and import on another.

What browsers are supported?

Any modern browser: Chrome, Firefox, Safari, Edge. Works on desktop, tablet, and mobile.

Can I add more countries/currencies?

Yes — the web app includes every country and active currency, matching the mobile app. If you don't see what you need, you can just type your own.

Is my data backed up?

No automatic backups. Export your collection regularly as CSV files for backup. Store these somewhere safe (cloud drive, email to yourself, etc.). The CSV file can also be imported into the mobile app.

Can I print my collection?

Export to CSV, then open in Excel/Google Sheets and print from there. Or use your browser's print function on the table view.

How do I delete everything?

Open browser DevTools (F12), go to Application > Local Storage > your domain, delete the zenkasu_items key. Or just clear your browser's local storage for the site.

Is there a mobile app?

Yes — the Android app is available now on Google Play. An iOS app is coming soon. The web app and mobile app share the same data structure — export CSV from web, import on mobile (CSV import/export on mobile is a Pro feature). The web app also works on mobile browsers if you need something right now.

Ready to get started?

Launch Zenkasu