I’m building an integration using the ServiceM8 API and have created a custom selectlist field on the Job object called “Inspection Approved” (UUID: 173d2179-6a21-4426-a873-242f6421abeb).
I’m trying to subscribe to changes on this field using the Object Webhook endpoint (POST /webhook_subscriptions/object), but when I pass the field UUID or the field name in the fields parameter, I get the error: “is not a valid field for subscription”.
Could you confirm:
Is it possible to subscribe to custom job field changes via the object webhook?
If not, is there another recommended way to get notified when a specific custom field value changes on a job without polling?
For object webhooks, the fields parameter is a comma-separated list of fields on the object, and a webhook is sent when any of the specified fields change.
Custom fields are commonly used in conjunction with webhooks, and their REST API field name is your field_name prefixed with customfield_ (for example customfield_favourite_ice_cream).
Because webhook field subscriptions are defined using API field names, the usual approach is to subscribe to your custom job field using customfield_<your_field_name> (you can confirm the field_name via GET /custom_fields_1.0).
When the webhook fires, the payload only indicates which field(s) changed (it doesn’t include the new value), so you’ll then fetch the Job via the resource_url and read the custom field value from the Job record.
If you still can’t get customfield_<your_field_name> accepted, the closest “no polling” fallback is subscribing to the job.updated event webhook and then retrieving the Job via the REST API to evaluate the custom field value.
If you try the customfield_ field name and it’s still failing, email support@servicem8.com with the exact subscription request you’re sending and the full error response so we can confirm what’s happening.