Barcode Generator

Generate more than 100 linear, retail, postal, medical, stacked, and two-dimensional barcode formats as downloadable SVG or PNG images.

Description

Generate downloadable SVG and PNG images for more than 100 linear, retail, matrix, stacked, postal, medical, and publishing barcode symbologies.

A barcode represents data with machine-readable geometric patterns. This generator exposes 103 non-QR encoders spanning common linear symbols such as Code 128 and Code 39; retail and publishing symbols such as EAN, UPC, ISBN, and ISSN; matrix and stacked symbols such as Data Matrix, Aztec, PDF417, and DotCode; and specialized postal, pharmaceutical, healthcare, and GS1 formats. Each result is generated locally as vector SVG and can also be downloaded as PNG.^{[1, 2]}

When to use a barcode

Choose the symbology required by the system that will scan the result. Code 128 is a compact general-purpose choice for ASCII data, while EAN and UPC are used with assigned retail identifiers. Data Matrix is common for small-item marking, PDF417 can carry larger records, and postal and medical formats follow jurisdictional or industry specifications. A visually generated code does not allocate an identifier or make unregistered data valid for a supply chain.

Family	Representative formats	Typical role
Linear	Code 128, Code 39, Codabar, Interleaved 2 of 5	General identifiers and legacy systems
Retail and publishing	EAN-13, UPC-A, ISBN, ISSN, GS1-128	Products, publications, and logistics
Matrix	Data Matrix, Aztec, DotCode, MaxiCode	Dense data and direct marking
Stacked	PDF417, MicroPDF417, Codablock F	Larger payloads in a rectangular symbol
Postal	Intelligent Mail, Royal Mail, Japan Post	Mail routing under postal specifications
Medical	HIBC and pharmaceutical codes	Regulated healthcare identifiers

How to use the Barcode Generator

Choose the barcode type required by the system that will read it; the route changes to a shareable URL for that symbology. Replace the sample content with the value to encode, then adjust scale, bar height, rotation, padding, colors, and optional human-readable text. Frame and branding options can add a border or place a tool.io or uploaded logo outside the protected barcode area. Download SVG for printing and layout work or PNG for raster use.

Select the exact symbology specified by the retailer, publisher, postal service, medical workflow, or receiving application.
Enter the identifier in that format's required character set and length; use the displayed encoder error to correct invalid data.
Set bar height and scale for the intended physical output without stretching the downloaded image afterward.
Keep dark bars on a light background and preserve sufficient padding around the complete symbol.
Verify the final printed or displayed result with the actual scanner and workflow that will consume it.

How barcode encoding works

The selected encoder validates the content, calculates any format-defined check characters, converts the result to bars or two-dimensional modules, and applies required guards and structural patterns. The renderer then scales that geometry without converting it to a font. Human-readable text is a separate printed aid and is not what the scanner decodes.^{[3, 1]}

Resolve the selected route and encoder identifier through the complete supported-symbology registry.
Validate the payload under that symbology's character, length, and check-digit rules.
Generate bars, modules, finder structures, and optional human-readable text with the standards-based encoder.
Apply scale, bar height where relevant, rotation, quiet padding, foreground color, and background color.
Return portable SVG plus measured dimensions, then rasterize locally only when PNG is requested.

Colors, dimensions, and custom design

Colors may be customized, but dark bars on a light uniform background are the safest choice. Scale, bar height, quiet zones, and rotation are exposed because scanners and printing processes need different physical sizes. Bar shapes remain rectangular and logos are not placed over linear barcodes: rounded, interrupted, or covered bars change the measured pattern. If branding is needed, place a logo outside the exported symbol and preserve its quiet zone.

Limitations and validation requirements

A correct image is not proof that its identifier was assigned by GS1, an ISBN agency, a postal operator, or another authority.
Different symbologies accept different character sets, lengths, application identifiers, and check-digit conventions; an encoder error usually means the payload violates the selected format.
Screen previews do not predict final print quality, ink spread, substrate contrast, magnification, or scanner optics.
Changing aspect ratio after export can alter bar widths and make a symbol unreadable.
Production labels should be verified with the equipment and conformance process required by their industry.

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Alternative or Complementary approaches

Use a QR Code when ordinary phones should open a URL or consume a contact, Wi-Fi, location, event, or authenticator payload. Use RFID or NFC when contactless reading without line of sight is a system requirement. Keep human-readable identifiers beside operational barcodes where the governing standard permits it, and store authoritative product or session data on the server instead of attempting to encode an entire mutable record into the symbol.

References

Barcode Writer in Pure PostScript — BWIPP project
Barcodes — GS1
Barcode Writer in Pure JavaScript — bwip-js project

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