Get Cart Key from Webhook

Topic summary

Shopify Storefront API change now requires a cart key alongside the cart ID for cart mutations. Developers report they cannot find a way to obtain this key.

  • Not available via standard queries (e.g., GetCartFromId).
  • Not included in CARTS_UPDATE webhook payloads.
  • Updating to the latest API version did not resolve access to the key.

Key terms:

  • Cart ID: primary identifier for a cart.
  • Cart key: new additional identifier now required for mutations.
  • CARTS_UPDATE webhook: event payload used to react to cart changes.

Open issues/questions:

  • How to retrieve the cart key when only the cart ID is available (e.g., from webhooks)?
  • Whether Shopify will expose the key via queries or webhooks.

Status: Unresolved; no solution or official guidance provided in the thread yet.

Summarized with AI on December 18. AI used: gpt-5.

Also looking for a solution. Migrated app to latest API but this does not help