API Schema Reference

The primary endpoint /api/v3/label accepts a JSON array of LabelRequest objects.

Root Object: LabelRequest

Field	Type	Description
tracking_number	String	Optional identifier for the request.
items	Array<Item>	Required. List of content elements to draw on the PDF.
pdf_params	PdfParams	Configuration for the PDF document itself (size, metadata, profile).

PdfParams (Document Settings)

Controls the physical properties and metadata of the generated PDF.

Field	Type	Description
width	float	Page width in millimeters (mm).
height	float	Page height in millimeters (mm).
pdf_profile	String	Compliance level (e.g., "pdfa-1b", "" for standard). See Profiles.
metadata_title	String	Document title. Required for pdfa-ua1 (Trigger E003 if missing).
metadata_authors	String	Author name(s).
metadata_subject	String	Subject/Keywords.
metadata_producer	String	Software producer name.
metadata_language	String	ISO 639-1 code (e.g., "en"). Auto-detected if missing.

Item (Content Container)

A container for various graphical elements. All fields are optional arrays.

Field	Type	Description
1d_params	Array<OneDParams>	Linear barcodes (Code128, Code39, EAN, etc.).
2d_params	Array<TwoDParams>	Matrix barcodes (QRCode, DataMatrix, PDF417).
text_elements	Array<TextElement>	Absolute positioned text.
lines	Array<Line>	Vector lines.
images	Array<ImageElement>	Raster images (JPG/PNG).
rectangles	Array<Rectangle>	Vector rectangles.

OneDParams (Linear Barcodes)

Field	Type	Description
one_d_content	String	Data to encode.
format	String	Symbology: Code128, Code39, EAN13, etc.
size	BarcodeSize	Object containing width, height, module_width.
position	Position	Object containing x, y coordinates.
color	String	Barcode color (Hex, e.g., #000000).
human_readable_text	HumanReadableText	Text attached to the barcode.
background_color	String	Background fill color.
quiet_zone	int	Quiet zone in modules.

TwoDParams (Matrix Barcodes)

Field	Type	Description
two_d_content	String	Data to encode.
format	String	Symbology: QRCode, DataMatrix, PDF417.
module_size	float	Size of a single module (pixel) in mm.
x	float	X coordinate.
y	float	Y coordinate.

TextElement (Absolute Text)

Field	Type	Description
content	String	Text content to display.
x	float	X coordinate.
y	float	Y coordinate.
font_size	float	Font size in points (pt).
font_name	String	Font family name (must be pre-loaded).
bold	bool	Toggle bold weight.
align	String	Alignment: Left, Center, Right.
color	String	Text color (Hex).