Create a cart with POST /v3/carts using the Store Management API (X-Auth-Token header); include line_items array with product_id, variant_id, and quantity
Create a checkout from the cart by calling GET /v3/checkouts/CART_ID — BigCommerce creates a checkout object automatically when a cart is fetched via this endpoint
Add a billing address with POST /v3/checkouts/CHECKOUT_ID/billing-address supplying address object fields including first_name, last_name, address1, city, state_or_province, postal_code, country_code, and email
Add a consignment (shipping address + line item mapping) with POST /v3/checkouts/CHECKOUT_ID/consignments; the response includes available shipping_options for the address
Select a shipping option with PUT /v3/checkouts/CHECKOUT_ID/consignments/CONSIGNMENT_ID with shipping_option_id from the previous response
Create an order from the finalized checkout with POST /v3/checkouts/CHECKOUT_ID/orders; process payment separately using the Payments API with POST /v2/payments
Known gotchas
The Management API requires a Store API Account token (X-Auth-Token) with store_v2_orders_write and store_v2_carts_write scopes; using a customer-facing JWT token for Management API calls returns 403
Order creation (POST /v3/checkouts/CHECKOUT_ID/orders) does not process payment — it only creates an order in pending status; payment must be submitted via the BigCommerce Payments API separately
BigCommerce REST API rate limits are 150 requests per 30 seconds for standard plans; high-volume headless checkout flows must implement exponential backoff on 429 responses
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claude mcp add --transport http waymark https://mcp.waymark.network/mcp