Automatically add a flat rate shipping price of $9.99 to draft orders

Shopify Plus

Topic summary

A user is attempting to configure a Shopify Flow to automatically add a $9.99 flat rate shipping charge to draft orders but is encountering an error.

Error Details:

  • The system returns an “invalid JSON” error message
  • The error indicates the Liquid code doesn’t form valid JSON after evaluation

Technical Context:

  • The user is working with a mutation input for draft orders
  • They’re trying to set up a shipping line with:
    • Price: $9.99 AUD
    • Title: “Standard”
    • Shipping rate handle: “Standard”

Current Status:

  • The flow configuration appears incomplete or malformed
  • The JSON structure in the code snippet shows formatting issues
  • No solution has been provided yet; the issue remains unresolved
Summarized with AI on November 3. AI used: claude-sonnet-4-5-20250929.
1

Please see attached flow set up, receiving the error: Mutation input evaluated to invalid JSON. Please ensure the input forms valid JSON after Liquid code is run.

2

{
“id”: “{{draftOrder.id}}”,
“input”: {

“shippingLine”: {
“priceWithCurrency”: {
“amount”: “9.99”,
“currencyCode”: “AUD”
},
“shippingRateHandle”: “Standard”,
“title”: “Standard”
},

}
}