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BillBook
VAT-ready invoicing, built around GRA rules
Invoicing for Guyanese businesses without an accountant. It knows the 14% VAT rule, numbers documents the way the GRA expects, and sends them over WhatsApp because that's where the customer already is.
What we built
- Quotes, invoices, receipts and credit notes, numbered automatically the way the GRA asks
- 14% VAT worked out line by line, in whole G$
- WhatsApp sharing, overdue reminders and a “how to pay” page
- Stock, expenses and a monthly VAT report — with AI that reads receipts and counts shelves
The standout
From quote to paid, in one flow built around Guyana's rules
A quote becomes a numbered tax invoice in one tap and goes out on WhatsApp as a link. Record the payment and the receipt issues itself. VAT is worked out line by line — 14%, zero-rated or exempt — and the month's VAT summary is ready before the 21st.
- 01 · QuoteSent on WhatsApp
- 02 · InvoiceOne tap, auto-numbered
- 03 · Get paidCustomer taps “I've paid”
- 04 · ReceiptIssues when you record the payment
- 05 · ChaseOverdue → WhatsApp nudge
- 06 · FileVAT summary by the 21st
circled — the part that makes it worth building
Inside the app
Screen by screen — what each part does.
Real screens from the working product, with the job each one does for the business.
Dashboard
The first thing you see each morning
Money collected and invoiced against the last 30 days, payments by day, your collection rate and who owes you the most.
Who owes you most, and anything overdue, is one tap from the documents behind it.
Documents
Every document, one list
Filter by type and status. Paid, part-paid and overdue at a glance, each with its own serial number.
Once a payment is recorded, an invoice is locked, and any fix goes on a credit note.
Print designs
An invoice that looks like you
Five print designs — this is Editorial. Your logo, colour and bank details, with the VAT worked out on every line.
This one is part-paid: record a payment and the balance due updates everywhere.
Getting paid
What your customer sees
The WhatsApp link opens your invoice, how to pay you by bank or MMG, and an “I've paid” button that messages you straight away.
The money goes straight to you — BillBook never sits in the middle.
Stock
Stock that keeps count
Single units or packs, low-stock alerts, what the shelf is worth, and margin by item over 7, 30 or 90 days.
AI stock scan
Count a shelf from a photo
Take a photo of a shelf or fridge and AI drafts the count. You check it, then save.
VAT
VAT, set once
14% by default. Change the rate once and every new document follows, while old ones keep the rate they were billed at.
The breakdown
Everything it does, for the people using it.
12 things this product handles — most of them invisible until you need them.
What you do in it
Five official document types
Quotes, tax invoices, sales invoices, receipts and credit notes from one form — with a warning when a cash sale passes GRA's G$10,000 limit.
WhatsApp sharing
One tap sends a private link. The customer sees your invoice, your bank and MMG details, a PDF download and an “I've paid” button.
Overdue reminders
A polite WhatsApp nudge that says exactly how many days late it is.
Your brand on every page
Logo, brand colour and five print designs — plus an 80 mm receipt layout for counter printers.
Customers and statements
A balance for every customer, printable statements with an aging breakdown, and your own custom fields.
What it handles for you
Automatic serial numbers
Every document type gets its own series — INV-, QUO-, REC-, CRN- — the individual serials the GRA asks for.
VAT per line, rate-proof
14%, zero-rated or exempt on every line. If the rate ever changes, old documents keep the rate they were billed at.
A monthly VAT report and P&L
Taxable sales, output VAT and every document behind them, with a CSV to prepare the filing.
Expenses, with AI that reads receipts
Snap a receipt and AI fills in the vendor, total, date and category for you to check.
Stock, with AI photo counts
Units or packs, low-stock alerts, shelf value and margin by item — and a draft count from a photo of the shelf.
A cash & float drawer
For MMG agents and anyone who lends: top-ups, loans, repayments and fees, with lending kept out of profit.
Tristan, inside the app
An AI helper that answers questions and takes you to the right button.
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