Printing & PDF

Print 80 mm thermal receipts directly from the browser, download the invoice PDF, and understand what each document shows — including the UPI QR code.

Kapda Stock produces three printable documents for every sale. All are generated by the server, so they look the same whichever device you print from.

Document	Best for	Where
Thermal receipt (80 mm)	The counter	POS → Print thermal / Thermal preview; Invoices → ⋯ → Thermal receipt (80mm)
Invoice PDF (A5)	Any printer, B2B customers, records, email, WhatsApp	POS → PDF receipt; Invoices → PDF — the same document

Thermal receipts#

Print thermal sends ESC/POS commands straight to a thermal printer connected by USB or serial.

Use Chrome or Edge on a desktop or laptop — the direct print uses the browser's Web Serial feature, which phones and Safari do not support.
Connect the printer and switch it on.
Complete a sale in POS and click Print thermal on the Last sale completed bar.
The first time, the browser lists serial ports — choose the printer and click Connect.
You see Receipt sent to the thermal printer.

The connection runs at 9600 baud, the default for most 80 mm ESC/POS printers. If your printer is set to a different speed, change the printer's setting to 9600.

What the thermal receipt shows#

Business name (large), address and GSTIN
Invoice number and date (IST)
Each item: description (up to 42 characters), quantity × rate, line total
Taxable value, then CGST and SGST — or IGST for an inter-state sale
TOTAL in large print
Paid: the payment summary
Scan to pay via UPI with a QR code (QR model 2, module size 6), when a UPI ID is set
Thank you! Visit again. and a paper cut

Invoice PDF#

One design for every invoice: the PDF from the POS, the PDF button on the Invoices page, and the copy emailed or sent on WhatsApp are the same A5 document. It contains:

Your business details and GSTIN
The customer's name and phone — and, for a business customer with a GSTIN, their address and GSTIN; the title then reads Tax Invoice (otherwise Sale Receipt)
Invoice number, date and due date
Each line with its HSN and GST %, quantity, rate and amount
Sub-total, savings, Taxable value, CGST/SGST (or IGST for another state), Round off and TOTAL, with the amount in words
Payments received and a PAID IN FULL or BALANCE DUE stamp
A Scan to pay UPI QR code when a UPI ID is set
PROFORMA marking on proforma invoices
The Terms & Conditions from your default invoice template

The UPI QR code#

Set your UPI ID once in Invoicing settings. Every receipt and invoice then carries a QR code that opens GPay, PhonePe, Paytm, BHIM, JKPay or any UPI app with:

the payee set to your UPI ID,
the amount set to the invoice total, and
the note Invoice INV-….

The customer confirms in their app; money goes straight to your account. Record the payment in the app afterwards (it is not detected automatically). To have payments recorded automatically, use a Razorpay payment link instead.

Troubleshooting#

Symptom	Fix
Web Serial not supported in this browser — use the PDF receipt instead	Use desktop Chrome or Edge, or the Thermal preview PDF.
Thermal print failed: …	The port is busy (close other printing software), the printer is off, or you cancelled port selection. Try again.
Receipt prints garbled characters	The printer is not at 9600 baud or is not ESC/POS compatible — use the preview PDF.
No QR code on the receipt	Add a UPI ID in Settings → Invoicing.
GSTIN NOT SET on the invoice	Add your GSTIN in Settings → Shop details.