> ## Documentation Index
> Fetch the complete documentation index at: https://docs.thingidentity.com/llms.txt
> Use this file to discover all available pages before exploring further.
# Render 2D barcode
> Render one validated code definition as SVG.
Render one code as an SVG file. Send a single code definition, not a `codes` array.
The same GS1 validation used by [`POST /codes`](/api-reference/endpoints/generate-codes) applies.
This operation requires `write:codes` and does not save a generated-code record or a file.
## Barcode modes
| `mode` | Encoded data |
| --------------------------------- | ---------------------------------------------------------------- |
| `GS1_DATAMATRIX` | GS1 element string with FNC1, Data Matrix ECC 200. |
| `DATAMATRIX_GS1_DIGITAL_LINK_URI` | GS1 Digital Link URI in Data Matrix. Requires `digitalLinkStem`. |
| `GS1_QR` | GS1 element string with FNC1 in QR Code. |
| `QR_GS1_DIGITAL_LINK_URI` | GS1 Digital Link URI in QR Code. Requires `digitalLinkStem`. |
For QR modes, optional `errorCorrectionLevel` accepts `L`, `M`, `Q` or `H`.
Omitting it or sending `null` selects `L`. The requested level is used without automatic upgrading.
Data Matrix uses fixed ECC 200: omit `errorCorrectionLevel` or send `null`; any other value is rejected.
`ais` and `extensionParameters` may be omitted or `null` for empty lists.
`linkType` and `context` are optional. Each response is a single file.
## Download an SVG
```bash theme={null}
curl --fail-with-body -X POST 'https://api.thingidentity.com/codes/render' \
-H "Authorization: Bearer $ACCESS_TOKEN" \
-H 'Content-Type: application/vnd.thingidentity.public.v1+json' \
-H 'Accept: image/svg+xml' \
--data '{
"mode": "QR_GS1_DIGITAL_LINK_URI",
"digitalLinkStem": "https://gtin.at",
"primaryKey": { "key": "01", "value": "09521234543213" },
"ais": [{ "key": "10", "value": "LOT42" }]
}' \
--output code.svg
```
Success returns `200 OK` with `Content-Type: image/svg+xml`.
Example response body, shown as SVG source:
```xml theme={null}
```
The SVG is black on white, with quiet zones of four modules for QR and one for Data Matrix.
It contains no printed human-readable label.
Invalid requests or codes that cannot be rendered return `400 Bad Request` with an empty body.
For GS1 validation details in JSON, submit the code definition to
[`POST /codes`](/api-reference/endpoints/generate-codes), wrapped in a `codes` array.
## OpenAPI
````yaml openapi.json POST /codes/render
openapi: 3.1.0
info:
title: Thing Identity Public API
version: 1.0.0
description: >-
Machine-to-machine API for Thing Identity. Authenticate with client
credentials, then call the endpoints below with the resulting bearer token.
servers:
- url: https://api.thingidentity.com
security:
- bearerAuth: []
tags:
- name: Authentication
description: Exchange client credentials for an access token.
- name: Codes
description: Generate GS1 barcode payloads and GS1 Digital Link URIs.
paths:
/codes/render:
post:
tags:
- Codes
summary: Render 2D barcode
description: Render one validated code definition as SVG.
operationId: renderCode
requestBody:
required: true
content:
application/vnd.thingidentity.public.v1+json:
schema:
$ref: '#/components/schemas/RenderCodeRequest'
example:
mode: QR_GS1_DIGITAL_LINK_URI
digitalLinkStem: https://gtin.at
primaryKey:
key: '01'
value: '09521234543213'
ais:
- key: '10'
value: LOT42
application/json:
schema:
$ref: '#/components/schemas/RenderCodeRequest'
example:
mode: QR_GS1_DIGITAL_LINK_URI
digitalLinkStem: https://gtin.at
primaryKey:
key: '01'
value: '09521234543213'
ais:
- key: '10'
value: LOT42
responses:
'200':
description: SVG barcode image.
content:
image/svg+xml:
schema:
type: string
example: >-
'400':
description: >-
Invalid request, code definition, mode, correction level or
unrenderable data. Empty response body.
'401':
description: Missing or invalid bearer token.
'403':
description: Token lacks write:codes or API access.
'406':
description: Accept does not allow image/svg+xml.
components:
schemas:
RenderCodeRequest:
example:
mode: QR_GS1_DIGITAL_LINK_URI
digitalLinkStem: https://gtin.at
primaryKey:
key: '01'
value: '09521234543213'
ais:
- key: '10'
value: LOT42
type: object
required:
- mode
- primaryKey
properties:
mode:
type: string
enum:
- GS1_DATAMATRIX
- DATAMATRIX_GS1_DIGITAL_LINK_URI
- GS1_QR
- QR_GS1_DIGITAL_LINK_URI
example: QR_GS1_DIGITAL_LINK_URI
description: Barcode type. Digital Link modes require digitalLinkStem.
errorCorrectionLevel:
type:
- string
- 'null'
enum:
- L
- M
- Q
- H
- null
description: >-
QR only: L, M, Q or H. Omitted or null selects L for QR. For Data
Matrix omit or send null.
primaryKey: 5b5f18e0-4792-4aa7-a871-12cf92cdf5ac
ais: 48607265-a799-4ae4-8234-730c8524b8e0
extensionParameters: 510686b0-509a-43a2-888a-a04b3677def6
digitalLinkStem: ecedb463-ce30-4ae5-95e1-e0183aff5709
linkType: 07369bee-8235-470d-a069-16104625187b
context: e820522b-5a1d-4d84-aed9-d3cbeb39d854
securitySchemes:
bearerAuth:
type: http
scheme: bearer
bearerFormat: JWT
description: The `access_token` from `POST /oauth/token`.
````