This endpoint generates custom thumbnails by compositing an overlay image on top of a base image. It’s used for creating social media preview images with branded overlays.
Endpoint
POST /api/thumbnail/generate
Request body
This endpoint accepts multipart form data with the following fields:
The ID of the overlay image to apply. The overlay is fetched from /overlays/{overlayId}.png
Whether to horizontally flip the overlay image. Defaults to false
The base image file to apply the overlay to. Either this or originalThumbnail is required
URL to fetch the base image from. Either this or file is required
Response
Returns the generated thumbnail as a JPEG image with Content-Type: image/jpg.
Use case
This endpoint is used to generate Open Graph thumbnails for social media sharing. When a link to KommtKevinOnline is shared on platforms like Twitter, Discord, or Facebook, a custom thumbnail with branding overlay is displayed.
The overlay is composited on top of the base image (either uploaded or fetched from a URL) and can be flipped horizontally for different layouts.
Example
Request (with file upload)
curl -X POST https://kommtkevinonline.de/api/thumbnail/generate \
-F "overlayId=default" \
-F "flipX=false" \
-F "[email protected]"
Request (with URL)
curl -X POST https://kommtkevinonline.de/api/thumbnail/generate \
-F "overlayId=default" \
-F "flipX=true" \
-F "originalThumbnail=https://example.com/image.jpg"
Response
Returns a JPEG image binary with the overlay applied.