A4 invoices & HTML pages¶

For full-page invoices, quotes and reports, send an HTML page to an A4/A5 printer. It's printed through the printer's own driver as sharp vector text.

A4 / A5 documents¶

POST /print/document

Field	Type	Notes
`html` or `pdfBase64`	string	A complete HTML page, or a base64 PDF (macOS/Linux only for now)
`printer`	string	API name, e.g. `"invoice"`. Default: the default A4 printer
`paperSize`	string	`A4`, `A5`, `Letter` or `Legal`. Default: the printer's setting
`landscape`	boolean	Default `false`
`copies`	1–20	Default `1`
`title`	string	Shown in the printer queue, e.g. `"Invoice INV-1042"`

await fetch('http://127.0.0.1:9191/print/document', {
  method: 'POST',
  headers: { Authorization: `Bearer ${TOKEN}`, 'Content-Type': 'application/json' },
  body: JSON.stringify({
    printer: 'invoice',
    paperSize: 'A4',
    title: 'Invoice INV-1042',
    html: `<!doctype html><html><head><meta charset="utf-8"><style>
             @page { margin: 15mm; } body { font-family: Arial, sans-serif; }
           </style></head><body><h1>Invoice INV-1042</h1>…</body></html>`,
  }),
});

Tips for invoice HTML¶

Send one self-contained page. Put CSS in a <style> tag and embed logos as data: URLs. Pages render with no network access.
JavaScript is turned off. Render the final HTML in your POS (a template engine, React renderToString…) before sending it.
QR codes: generate them in the POS (e.g. with the qrcode npm package) and embed them as inline <svg> or a data: image.
Set margins with @page { margin: 15mm; }, and use page-break-inside: avoid on table rows so long invoices break cleanly.

A4 without writing HTML

Send a receipt to an A4 printer ("printer": "invoice") and the bridge lays the same lines out as a page.

HTML bills on a thermal printer¶

POST /print/page

{ "html": "<!doctype html>…", "format": "80mm", "printer": "receipt", "copies": 1, "title": "Bill #1042" }

Prints a page your POS designed for a receipt roll. format is the paper the page was laid out for: 80mm, 58mm, a4 or a5. How a thermal printer prints it depends on its Print bills setting:

Printer driver — the page goes through the printer maker's driver, at the printer's full resolution, on a page exactly as long as the bill. Needs the maker's driver installed (not Generic / Text Only).
Direct — the page is rendered to a black-and-white image at the print head's width. Works on any printer, but text is less sharp.
Auto (default) — the driver when the printer has one, otherwise direct.

Prefer line-by-line receipts

HTML on a thermal printer is never as sharp, small or reliable as a line-by-line receipt. Use /print/page only when you must reproduce an exact design, such as a logo-heavy layout.

ReceiptLine¶

POST /print/receiptline

{ "document": "^^^My Shop\nBill | #1042\n-\n^^TOTAL | ^^LKR 1,250.00", "printer": "receipt", "copies": 1, "cut": true }

ReceiptLine is an open "Markdown for receipts" with barcodes, logos and tables. The bridge prints it with the printer's own fonts, laid out for the printer's width and character set. POST /preview/receiptline with the same body returns { svg, cpl, printer } to show on screen. The SDK builds ReceiptLine with receipt() — see SDK.