Every page gets a share card the platform draws
Publish a page on Giant Context and its social share card is already made. The site's logo and colours, the brand's configured fonts, an image taken from the page itself, and the page's tags rendered as chips. Page settings shows you the card and redraws it as you type the title and description, on drafts as well as on published pages. A Site Name field sits alongside it, so titles compose as Page Title | Site Name rather than as whatever the page happens to be called internally.
How it chooses the image
The card is not guessing. An explicit SEO image wins if the page has one. Otherwise the card takes the first image that appears on the page, in the order the page is laid out. Otherwise it falls back to a text-forward layout built around the logo, with the palette picked against the background's luminance so the type stays legible. The same page produces the same card every time.
It is also drawn rather than photographed. A screenshot of the top of a page crops wherever the crop falls, usually across a heading, and a page built for a browser window has to be cut down to fit 1200 by 630. Rendering from the page's own data instead composes the card for the frame it will appear in.
Building something like this
I'm Jesse. I build platforms end to end, and I'm open to work. If this is the kind of engineering you need, get in touch.