Filter Invoices by Customer (Entity) on REST API

Hi all,

I am using the NetSuite REST API Tutorial. I can successfully GET specific invoice IDs (e.g. {{REST_SERVICES}}/record/v1/invoice/<invoice.id>?expandSubResources=true

My next step is to GET all invoices for a specific customer. Looking at the schema, plus the response from the individual invoice, it looks like i should be filtering by entity.

https://www.netsuite.com/help/helpcenter/en_US/srbrowser/Browser2016_1/schema/record/invoice.html

"entity": {
"links": [
{
"rel": "self",
"href": "https://<account.id>.suitetalk.api.netsuite.com/services/rest/record/v1/customer/<customer.id>"
}
],
"id": "<customer.id>",
"refName": "<customer.name>"
},

However, I cannot seem to get this to work.

I am using EQUAL in the q for entity, entityId, entity.ID and the like on the get request, but no love. Also tried CONTAIN (incase it is a string, unlikely) – as from https://docs.oracle.com/en/cloud/saas/netsuite/ns-online-help/section_1545222128.html

Anyone got a quick pointer on how this can work? I feel like this should be simple but unfortunately stuck in the weeds now.

ex: GET {{REST_SERVICES}}/record/v1/invoice?q=entity EQUAL ‘<customer.id>’
response

{
"type": "https://www.rfc-editor.org/rfc/rfc9110.html#section-15.5.1",
"title": "Bad Request",
"status": 400,
"o:errorDetails": [
{
"detail": "Invalid search query. Provide a valid search query.",
"o:errorQueryParam": "q",
"o:errorCode": "INVALID_PARAMETER"
}
]
}