INVALID_FUNCTION error on GetRESTProxy in Studio Snippet

Trying to hit an internal endpoint from a Studio flow. The code looks right based on the docs, but the flow fails immediately with INVALID_FUNCTION.

Here’s the snippet:

GetRESTProxy("crm_lookup", "https://internal-api.example.com/v1/customer", "GET", "", "", "application/json")

The function name is registered. The URL is valid. I’ve verified the outbound firewall rules. It works in Postman.

Is there a specific syntax requirement for the headers or body parameters that I’m missing? The error log doesn’t give much detail. Just says the function is invalid.

I’ve tried adding dummy headers. Same result.

Maybe the issue is with how I’m escaping the URL? Or is GetRESTProxy deprecated for custom DFO channels?

Any pointers on the correct call structure?

Check the function name case. Studio is strict about crm_lookup matching the registered function exactly. Also, the empty strings for headers and body might cause a parse error if the schema expects objects. Try passing null instead of empty strings for optional fields.

GetRESTProxy("crm_lookup", "https://internal-api.example.com/v1/customer", "GET", null, null, "application/json")