StackFill API and embed docs.

What you can do

• Create and list templates from approved PDFs.
• Map storefront product IDs and variants to live templates.
• Create browser or server-minted embed sessions.
• Save customer personalization back to a cart or order.
• Render final PDFs through authenticated server calls.
• Subscribe to webhook events for saved sessions and renders.

What it is not

• Not a storefront, cart, MIS, or payment processor.
• Not a browser-only final print renderer.
• Not a way to expose secret API keys in frontend code.
• Not a design-from-blank-canvas API.

Browser widget quick start

Use this when the shopper personalizes before adding a product to cart.

<script src="https://cdn.stackfill.com/widget/v1.js" async></script>
<button
  data-stackfill-open
  data-stackfill-key="stackfill_live_pk_REPLACE_ME"
  data-stackfill-product="business-card"
  data-stackfill-variant="standard">
  Personalize
</button>

window.addEventListener('stackfill:saved', (event) => {
  cart.attach({ stackfill_fill_id: event.detail.fill.id });
});

Read the embed widget guide

Server-minted session quick start

Use this when your backend controls customer, cart, order, or metadata values.

curl https://api.stackfill.com/v1/embed/sessions \
  -H "Authorization: Bearer stackfill_live_sk_REPLACE_ME" \
  -H "Content-Type: application/json" \
  -d '{
    "external_product_id": "business-card",
    "external_cart_id": "cart_123",
    "customer": { "email": "customer@example.com" }
  }'

Read the server sessions guide