A sale card for every product, straight from the catalogue.

# 1. Copy the product sale starter into your account; its id is your template
curl -s https://api.imageapis.com/v1/starters/product-sale -H 'X-API-Key: YOUR_KEY' | jq .template > card.json
curl -X POST https://api.imageapis.com/v1/templates -H 'X-API-Key: YOUR_KEY' \
  -H 'Content-Type: application/json' -d @card.json
# → { "id": "tpl_…", "object": "template", … }

# 2. For product pages: a signed base that can render that template and nothing else
curl -X POST https://api.imageapis.com/v1/signed-bases -H 'X-API-Key: YOUR_KEY' \
  -H 'Content-Type: application/json' -d '{"name":"product cards","template":"tpl_…"}'
# → { "id": "sb_…", "secret": "sbs_…", … }

{%- comment -%}
  snippets/imageapis-card.liquid. In Dawn, render it from snippets/meta-tags.liquid in place of the og:image
  and twitter:image tags on product pages:
    {% if request.page_type == 'product' %}{% render 'imageapis-card', product: product %}{% endif %}
  Theme settings hold imageapis_template (tpl_…), imageapis_base (sb_…) and imageapis_secret (sbs_…).
{%- endcomment -%}
{%- if product.compare_at_price > product.price -%}
  {%- assign off = product.compare_at_price | minus: product.price | times: 100 | divided_by: product.compare_at_price -%}
  {%- assign badge = off | prepend: '-' | append: '%' -%}
  {%- assign note = product.compare_at_price | money_without_trailing_zeros | prepend: 'Was ' -%}
{%- else -%}
  {%- assign badge = 'Free returns' -%}
  {%- assign note = 'In stock' -%}
{%- endif -%}
{%- if product.metafields.reviews.rating.value != blank -%}
  {%- capture rating -%}{{ product.metafields.reviews.rating.value.rating | round: 1 }} · {{ product.metafields.reviews.rating_count }} reviews{%- endcapture -%}
{%- else -%}
  {%- assign rating = 'New this season' -%}
{%- endif -%}
{%- capture query -%}
  store={{- shop.name | url_encode -}}
  &product={{- product.title | url_encode -}}
  &price={{- product.price | money_without_trailing_zeros | url_encode -}}
  &note={{- note | url_encode -}}
  &badge={{- badge | url_encode -}}
  &rating={{- rating | url_encode -}}
  &cta=Shop+now&photo={{- product.featured_image | image_url: width: 1200 | prepend: 'https:' | url_encode -}}
{%- endcapture -%}
{%- assign path = '/s/' | append: settings.imageapis_base | append: '/' | append: settings.imageapis_template | append: '.png?' | append: query -%}
{%- assign sig = path | hmac_sha256: settings.imageapis_secret -%}
{%- assign card = 'https://img.imageapis.com' | append: path | append: '&sig=' | append: sig -%}
<meta property="og:image" content="{{ card | escape }}">
<meta property="og:image:secure_url" content="{{ card | escape }}">
<meta property="og:image:width" content="1200">
<meta property="og:image:height" content="630">
<meta name="twitter:image" content="{{ card | escape }}">

<?php
// functions.php or a small plugin; in wp-config.php:
//   define('OG_TEMPLATE', 'tpl_…'); define('OG_BASE', 'sb_…'); define('OG_SECRET', 'sbs_…');

function imageapis_product_card_url(WC_Product $product): string {
    $plain   = fn ($s) => html_entity_decode(wp_strip_all_tags($s), ENT_QUOTES | ENT_HTML5, 'UTF-8');   // wc_price() is HTML
    $price   = (float) $product->get_price();
    $regular = (float) $product->get_regular_price();
    $on_sale = $product->is_on_sale() && $regular > $price;
    $reviews = $product->get_review_count();
    $query = http_build_query([
        'store'   => $plain(get_bloginfo('name')),
        'product' => $plain($product->get_name()),
        'price'   => $plain(wc_price($price)),
        'note'    => $on_sale ? 'Was ' . $plain(wc_price($regular)) : 'In stock',
        'badge'   => $on_sale ? '-' . round(100 * ($regular - $price) / $regular) . '%' : 'Free returns',
        'rating'  => $reviews ? sprintf('%.1f · %d reviews', $product->get_average_rating(), $reviews) : 'New this season',
        'cta'     => 'Shop now',
        'photo'   => wp_get_attachment_image_url($product->get_image_id(), 'large') ?: wc_placeholder_img_src('large'),
    ]);
    $msg = '/s/' . OG_BASE . '/' . OG_TEMPLATE . '.png?' . $query;
    return 'https://img.imageapis.com' . $msg . '&sig=' . hash_hmac('sha256', $msg, OG_SECRET);
}

add_action('wp_head', function () {
    if (!is_product()) return;
    $url = esc_url(imageapis_product_card_url(wc_get_product(get_the_ID())));
    echo "<meta property=\"og:image\" content=\"$url\">\n";
    echo "<meta name=\"twitter:card\" content=\"summary_large_image\">\n<meta name=\"twitter:image\" content=\"$url\">\n";
});

// Yoast SEO already prints og:image? Swap its URL instead of printing a second tag:
// add_filter('wpseo_opengraph_image', fn ($img) => is_product() ? imageapis_product_card_url(wc_get_product(get_the_ID())) : $img);

# products.csv: a column per {{placeholder}}; a layer.property column changes that layer for one row
# (empty cells keep the template's value); a column starting with _ comes back as metadata
store,product,price,note,badge,rating,cta,photo,product.size,product.font,note.font,rating.font,cta.font,_sku
Example Supply,Over-ear wireless headphones with noise cancelling,$139,Was $189,-26%,"4.6 · 2,184 reviews",Shop now,https://cdn.example.com/p/hp-1.jpg,,,,,,HP-1
Example Supply,Wasserdichter Tagesrucksack mit gepolstertem Laptopfach,89 €,Statt 119 €,-25 %,"4,8 · 912 Bewertungen",Jetzt kaufen,https://cdn.example.com/p/bp-2.jpg,,,,,,BP-2
Example Supply,"ステンレス保温ボトル
500ml 真空断熱","¥3,980","通常価格 ¥4,980",20%OFF,"4.7 · レビュー1,326件",今すぐ購入,https://cdn.example.com/p/wb-3.jpg,46,Noto Sans JP,Noto Sans JP,Noto Sans JP,Noto Sans JP,WB-3

curl -X POST "https://api.imageapis.com/v1/collections?template=tpl_…&webhook_url=https://shop.example.com/hooks/cards" \
  -H 'X-API-Key: YOUR_KEY' -H 'Content-Type: text/csv' --data-binary @products.csv
# → 202 { "id": "col_…", "status": "pending", "images": [
#          { "index": 0, "id": "img_…", "url": "https://img.imageapis.com/i/img_….png", "metadata": { "sku": "HP-1" } }, … ] }

# Once per merchant: their name, colours, fonts and logo
curl -X POST https://api.imageapis.com/v1/brands -H 'X-API-Key: YOUR_KEY' -H 'Content-Type: application/json' \
  -d '{"name":"Example Supply","logo":"https://cdn.example.com/logo.png",
       "colors":{"primary":"#16a34a","text":"#0b1220"},"fonts":{"heading":"Fraunces"}}'
# → { "id": "brand_…", "object": "brand", … }

# Once: in your copy of the sale card, point the layers at the brand
#   store   → "text": "{{brand.name}}"
#   product → "font": "{{brand.font.heading}}", "color": "{{brand.color.text}}"
#   sticker → "fill": "{{brand.color.primary}}"
#   cta     → "background": "{{brand.color.primary}}"

# Every render names the merchant's brand; the same template wears each one
curl -X POST https://api.imageapis.com/v1/images -H 'X-API-Key: YOUR_KEY' -H 'Content-Type: application/json' \
  -d '{"template":"tpl_…","brand":"brand_…","variables":{"product":"Over-ear wireless headphones","price":"$139",
       "note":"Was $189","badge":"-26%","rating":"4.6 · 2,184 reviews","cta":"Shop now","photo":"https://cdn.example.com/p/hp-1.jpg"}}'
# Collections take "brand" too, and so do signed URLs: …/tpl_….png?brand=brand_…&product=…&sig=…