Barcode Generation
The /barcode endpoint generates barcode images from a data string. It supports several standard barcode formats and renders the result as SVG or PNG.
GET/v5/barcode
Format details
- Code 128: Encodes any printable ASCII character (codes 32–126).
- EAN-13 / EAN-8 / UPC-A: Numeric only. The check digit is computed automatically if omitted, or validated if provided.
- Code 39: Alphanumeric (
A-Z,0-9, space,- . $ / + %). Input is auto-uppercased; start/stop characters are added automatically.
Parameters
| Parameter | Required | Default | Description |
|---|---|---|---|
data | Yes | Data string to encode in the barcode | |
type | No | code128 | Barcode format: code128, ean13, ean8, upca, code39 |
format | No | svg | Output format: svg or png |
width | No | 2 | Bar unit width in pixels (1–5) |
height | No | 100 | Bar height in pixels (50–300) |
color | No | #000000 | Bar color in hexadecimal (e.g. 000000) |
bg | No | #ffffff | Background color in hexadecimal (e.g. ffffff) |
Response
By default (format=svg), the endpoint returns an inline SVG image (Content-Type: image/svg+xml), usable in an <img> tag:
html
<img src="https://api.sylvain.sh/v5/barcode?data=Hello123" alt="Barcode" />With format=png, the response is a raw PNG buffer (Content-Type: image/png):
html
<img src="https://api.sylvain.sh/v5/barcode?data=Hello123&format=png" alt="Barcode" />Code Examples
curl -X GET \
"https://api.sylvain.sh/v5/barcode?data=Hello123&type=code128"Try It
Error Handling
| Error Message | Description |
|---|---|
Please provide data to encode (?data={string}) | The data parameter is missing |
Type must be one of: code128, ean13, ean8, upca, code39 | The type value is not valid |
Format must be one of: svg, png | The format value is not valid |
Width must be between 1 and 5 | The width parameter is out of the allowed range |
Height must be between 50 and 300 | The height parameter is out of the allowed range |
Please provide valid dimensions (&width={px}&height={px}) | The width or height parameter is not a valid number |
Code 128 only supports ASCII 32-126 (invalid char: "{ch}") | A character in data is outside the Code 128 supported range |
EAN-13 requires 12 or 13 digits | The data string does not have the correct number of digits |
Invalid EAN-13 check digit (expected {expected}, got {actual}) | The provided EAN-13 check digit does not match the computed value |
EAN-8 requires 7 or 8 digits | The data string does not have the correct number of digits |
Invalid EAN-8 check digit (expected {expected}, got {actual}) | The provided EAN-8 check digit does not match the computed value |
UPC-A requires 11 or 12 digits | The data string does not have the correct number of digits |
Code 39 invalid character: "{ch}". Allowed: A-Z, 0-9, space, - . $ / + % | A character in data is not allowed in Code 39 |
Invalid color (use hex like ff6600) | A color or bg value is not a valid hexadecimal color |