Invalid JSON creating invoice

1

I’ve already posted about this once - with no replies. I am using the API to create invoices and we’ve created hundreds of invoices automatically, so our system creates the JSON and sends it. However, we have one invoice on our system which is stuck and won’t create an invoice in FreeAgent. I’ve seen some posts about datatypes being incorrect cause an invalid JSON error - but I can’t see anything that is different to our other invoices. And I’ve tried removing the quotes from all number fields and it didn’t make a difference.

This is the JSON which has been sent - with the contact and invoice numbers changed to XXXX and with some of the number fields in quotes as all of our other invoices that have worked have been. However, I’ve tried another version which took out the quotes and it didn’t fix the problem:

{
“invoice”:{
“contact”:“https://api.freeagent.com/v2/contacts/XXXXXXXXX”,
“dated_on”:“2025-02-27”,
“due_on”:“2025-03-29”,
“reference”:“I-56157”,
“currency”:“GBP”,
“exchange_rate”:“1.0”,
“net_value”:“1966.5”,
“total_value”:“2359.8”,
“paid_value”:“0.0”,
“due_value”:“2359.8”,
“status”:“Open”,
“long_status”:“Open – due in 30 days”,
“omit_header”:false,
“always_show_bic_and_iban”:true,
“send_thank_you_emails”:false,
“send_reminder_emails”:false,
“send_new_invoice_emails”:false,
“bank_account”:“https://api.freeagent.com/v2/bank_accounts/XXXXXXX”,
“payment_terms_in_days”:30,
“payment_methods”:{
“paypal”:false,
“stripe”:false
},
“created_at”:“2025-02-27”,
“updated_at”:“2025-02-27”,
“invoice_items”:[
{
“description”:“XXXXXXXX”,
“price”:1966.5,
“sales_tax_rate”:“20”,
“quantity”:1
}
]
}
}

Any help would be gratefully received. Thanks!

2

Hi there Nick,

That sounds pretty frustrating - I’m keen to do some troubleshooting for you. Would it be possible for you to post the HTTP response here?

The JSON posted there seems to be correct, though I think something has automatically wrapped the quotes into speech marks. Can you check that it is formatted like

{
"invoice":{
"contact":"https://api.freeagent.com/v2/contacts/XXXXXXXXX",
"dated_on":"2025-02-27",
"due_on":"2025-03-29",
"reference":"I-56157",
"currency":"GBP",
"exchange_rate":"1.0",
"net_value":"1966.5",
"total_value":"2359.8",
"paid_value":"0.0",
"due_value":"2359.8",
"status":"Open",
"long_status":"Open – due in 30 days",
"omit_header":false,
"always_show_bic_and_iban":true,
"send_thank_you_emails":false,
"send_reminder_emails":false,
"send_new_invoice_emails":false,
"bank_account":"https://api.freeagent.com/v2/bank_accounts/XXXXXXX",
"payment_terms_in_days":30,
"payment_methods":{
"paypal":false,
"stripe":false
},
"created_at":"2025-02-27",
"updated_at":"2025-02-27",
"invoice_items":[
{
"description":"XXXXXXXX",
"price":1966.5,
"sales_tax_rate":"20",
"quantity":1
}
]
}
}

When you’re querying it to the API, I’m almost certain you will have done but it never hurts to check.

Thank you for your patience

Wil