Opus

Opus lets you record customer interactions using your own database of customers, staff, products, and/or services, then automatically pipes those totals straight into an accounting ledger. You mark them as paid whenever the cash hits, and it calculates balances on the fly. You can track expenses with whatever labels you want, and it makes clean, professional PDF invoices featuring your logo and payment info that you can instantly fire off via WhatsApp or email, or any other capable app on your phone. It does those things, and so much more, and is highly customizable to adjust to your specific business situation.

In short: invoicing, accounting, and customer logging—the three tools every small business actually needs to operate, minus the cloud subscription ransom.

And now, here's the full breakdown:

Opus: The Local-First Business Suite

Opus is a complete, offline-first business management, point-of-sale, and accounting suite for Android. Built with absolute data privacy, it supports solo operators and teams across Product Sellers, Service Sellers, or Hybrid Operations.

Manage multiple independent business locations or entities from a single app, each with its own isolated database, currency, tax rates, and inventory catalog. Configure flexible pricing—fixed items, custom quotes, or manual overrides—with automated taxes and discounts. Scale easily between Sole Trader Mode (all sales assigned to the owner) and Team Mode (multi-staff tracking).

Multi-Device Local Sync & Register Mode

Opus features a local-first WebSocket sync engine that links devices in real time without touching the cloud.

Flexible Local Networking: Connect a back-office master device to reception terminals over local Wi-Fi, or drop into direct device-to-device Wi-Fi hotspot mode when you're in the field—no internet required.

Financial & Administrative Control

Opus features an integrated double-entry accounting engine logging income alongside operational expenses like stock and rent. It monitors real-time cash flow, links sales to ledgers, and tracks invoice balances.

For clients, it generates branded A4 PDF invoices with custom logos, tax numbers, and payment details. Share them instantly via WhatsApp or email, complete with embedded payment QR codes, Digital PayIDs, SWIFT codes, and bank details.

Port data easily with PDF ledgers, CSV transaction exports, and bulk import/export tools. Protect records using the encrypted Master Vault backup system.

Intelligence, Customization & Our Promise

Analytics: Performance Analytics breaks down sales volume and top items. Financial Analytics tracks total revenue, expenses, and net profit margins.

Customization: Remap app terminology (Products, Services, Customers, Staff) to match your trade, upload business logos, and adjust currencies and tax structures.

The Promise: Opus will never collect your data, force you online, charge a subscription fee, or take away your control. With a generous free tier covering 100 logged customer interactions, try Opus today.