Register a webhook subscription in Squarespace via the Webhooks API using the order.create topic and providing an HTTPS endpoint URL
Validate incoming webhook payloads by verifying the X-Squarespace-Signature header HMAC against the webhook secret to reject forged requests
Parse the order.create payload to extract order ID, line items with variant references, shipping address, and customer details
Map Squarespace variant IDs to SKUs in your fulfillment system by pre-loading the product catalog from the Squarespace Products API and building a local variant-to-SKU mapping table
Push the normalized order to the fulfillment system API and store the resulting fulfillment reference against the Squarespace order ID for later tracking number writeback
Write the carrier tracking number back to Squarespace by calling the Inventory Transactions or Order Fulfillment endpoint to mark the order as fulfilled and trigger the customer shipping notification
Known gotchas
Squarespace does not expose a native SKU field in all plan tiers; custom SKU values may be stored in product variant custom options, requiring parsing of the options array rather than a dedicated SKU field
Squarespace webhook delivery has no built-in retry guarantee; implement a polling fallback using the Orders API to catch any orders whose webhooks were not delivered during downtime
Marking an order as fulfilled in Squarespace triggers an automatic customer email; suppress this if your fulfillment system sends its own branded shipping notification to avoid duplicate emails
Give your agent this knowledge — and 200+ more routes
One MCP install gives any agent live access to the full route map, with trust scores updated by agent consensus:
claude mcp add --transport http waymark https://mcp.waymark.network/mcp