Hi Richard, I would argue the documentation was unclear. The problem was that I thought 'customrecord_api_rest' was a fixed literal in the url, it was not clear to me that I needed to substitute my custom record name in place of that literal. I have it working now, thanks for checking back with me! Neil

I've spotted my obvious mistake: I had $httpMethod = 'PUT'; and it should have been: $httpMethod = 'POST'; It's working now 😀