invoicepdf

Render invoices and credit notes as PDF bytes. The package uses embedded fonts and needs no files, no configuration, and no external services.

Features

• Render returns the complete PDF in one call and never changes the document.
• Long item names and configurations wrap across lines and pages. A continuation page repeats the table header.
• Credit notes support negative amounts, an original-document reference, and a correction reason.
• Czech and English output. The Czech locale uses Faktura, Kč, comma decimals with non-breaking-space grouping, and 02.01.2006 dates. The English locale uses Invoice, 1,234.56, and 02 Jan 2006.
• Amounts use minor units as int64. Money formatting uses integer arithmetic only.
• An optional logo and an optional color palette.
• The paid or unpaid banner and the "not a VAT payer" note are part of the layout.

Install

go get github.com/m1chlcz/invoicepdf

Go 1.27 or later is required.

Quick start

document := invoicepdf.Document{
	Number:        "2026-0001",
	Kind:          invoicepdf.KindInvoice,
	IssuedDate:    "2026-09-19",
	SupplyDate:    "2026-09-18",
	Locale:        "cs-CZ",
	Currency:      "CZK",
	SellerName:    "Sample Goods s.r.o.",
	SellerAddress: "Ulice 12\n110 00 Praha 1",
	BuyerName:     "Jan Novák",
	BuyerAddress:  "Krátká 3\n602 00 Brno",
	Lines: []invoicepdf.Line{{
		Name:           "Kožená taška",
		Quantity:       1,
		UnitPriceMinor: 249000,
		TotalMinor:     249000,
	}},
	ItemsMinor:    249000,
	ShippingMinor: 12000,
	TotalMinor:    261000,
	Paid:          true,
}

pdf, err := invoicepdf.Render(document)
if err != nil {
	return err
}

Document fields

Field	Meaning
Number	Document number. It appears in the header and in the PDF title.
Kind	KindInvoice or KindCreditNote.
OriginalNumber	The corrected document. Credit notes only.
IssuedDate, SupplyDate	ISO dates (2006-01-02) or RFC 3339.
OrderNumber	Optional order reference.
Locale	A cs prefix selects Czech. Any other value selects English.
Currency	An ISO code. CZK becomes Kč in Czech.
SellerName, SellerID, SellerAddress, SellerEmail, SellerPhone	Seller details. SellerID is the company ID.
BuyerName, BuyerAddress, BuyerEmail	Buyer details.
Lines	Line items with Name, Configuration, Quantity, UnitPriceMinor, and TotalMinor.
ItemsMinor, ShippingMinor, DiscountMinor, TotalMinor	Amounts in minor units.
Reason	The correction reason. Credit notes only.
Paid	Shows the paid banner and the settled total label. A credit note always uses the settled label and has no banner.
Logo	Optional PNG or JPEG bytes. The header keeps a 3:1 ratio.
Palette	Optional color override.

Credit notes

Set Kind to KindCreditNote, set OriginalNumber, and use negative amounts. The renderer adds the original-document reference and the correction reason.

document.Kind = invoicepdf.KindCreditNote
document.OriginalNumber = "2026-0001"
document.Reason = "Returned goods."

Logo and colors

Logo accepts PNG or JPEG bytes. The renderer draws the logo in the header and skips the logo when the value is empty.

Palette replaces the built-in colors as a whole. Set every color that the document needs. An unset field is black.

document.Palette = &invoicepdf.Palette{
	Primary: invoicepdf.Color{R: 0x1F, G: 0x29, B: 0x37},
	Surface: invoicepdf.Color{R: 0xF1, G: 0xF5, B: 0xF9},
	Accent:  invoicepdf.Color{R: 0x47, G: 0x55, B: 0x69},
	Text:    invoicepdf.Color{R: 0x11, G: 0x18, B: 0x27},
	Muted:   invoicepdf.Color{R: 0x6B, G: 0x72, B: 0x80},
	Rule:    invoicepdf.Color{R: 0xE2, G: 0xE8, B: 0xF0},
	RowAlt:  invoicepdf.Color{R: 0xF8, G: 0xFA, B: 0xFC},
	White:   invoicepdf.Color{R: 0xFF, G: 0xFF, B: 0xFF},
}

Development

go test ./...

Set INVOICEPDF_SAMPLE_DIR to an absolute path to export sample PDFs:

INVOICEPDF_SAMPLE_DIR=/tmp/invoicepdf go test -run TestExportSamples -v

License

MIT. See LICENSE.