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DocumentationAPI ReferenceSDK

Essentials

Generate images

Learn how to generate PNG, JPEG, and WebP images from a template with the Bannerify API.

You send one request with a template id and the values to change, and the response body is the image. Bannerify renders the image while the request waits, so you can call it from a request handler, a background job, or a script.

Prerequisites

  • A template. Template editor shows how to build one, and the gallery has ready-made ones.
  • An API key. Create one on the API Keys page of the dashboard.
  • The template id. Open the menu on a template card and choose Copy Template ID.

Generate an image

  1. Name the layers you want to change. Modifications explains how.
  2. Send a POST request to /v1/templates/createImage with a JSON body:
curl --request POST \
  --url https://api.bannerify.co/v1/templates/createImage \
  --header 'Content-Type: application/json' \
  --output banner.png \
  --data '{
    "apiKey": "YOUR_API_KEY",
    "templateId": "tpl_xxx",
    "modifications": [
      { "name": "headline", "text": "Summer sale" }
    ]
  }'
  1. Read the response. The body is the image file, and the Content-Type header says which format it is: image/png, image/jpeg, or image/webp.

Always send the Content-Type: application/json header. A request without it fails with INTERNAL_SERVER_ERROR.

Options

Field Type Default Description
apiKey string Your API key. Required
templateId string The template to render. Required
modifications array, object, or JSON string [] The values to change. See Modifications
format png, jpeg, or webp png The image format. The value is case-sensitive, so jpg and JPEG fail
quality integer from 1 to 100 90 The encoder quality for jpeg and webp. png ignores it

The template sets the size of the image. A request cannot change the canvas.

PNG is lossless. JPEG and WebP make smaller files, and quality sets the trade-off between size and detail.

Try a template in the dashboard

The Form page under Generate lets you test a template without code. Its title is Template Playground.

  1. Choose a template in Select Template and a key in API Key. The page uses your first key until you choose another.
  2. Pick a layer under Elements. For a text layer, change Text Content on the Content tab or Text Color on the Style tab. For an image layer, enter an Image URL. The eye button next to a layer hides it.
  3. Click Generate Preview.

The page sends a real createImage request with the key you chose, so each preview counts as one generation. Download saves the PNG, and Copy puts it on the clipboard.

POST /v1/templates/createStoredImage takes the same body and returns a URL in place of the bytes:

{
  "url": "https://images.bannerify.co/files/0b3c1c1e-5d6f-4c52-9e0a-8f6a4c0f2a11.png"
}

Bannerify saves the file and serves it from its CDN at a public URL. This is useful when you want to put the link in an email, a database row, or a no-code tool. On the Business and Enterprise plans you can also send an s3Config object to save the file to your own S3-compatible bucket. Storage and notifications lists its fields.

A stored image counts as one generation.

Use an SDK

The SDKs send this request for you and return the bytes.

Language Page
JavaScript Create images and PDFs
Python Create images and PDFs
PHP Create images and PDFs
Go Create images and PDFs

Handle errors

A failed request returns JSON with an error object instead of an image. Read error.code to decide what to do next, and send error.requestId to support when you need help. Errors lists every code.