Workday RaaS returns data in Postman but not from ServiceNow (Date/Time query parameter issue)

[WilliedH]

Hi Community,

We are integrating ServiceNow → Workday Report-as-a-Service (RaaS) and are seeing inconsistent behavior between Postman and ServiceNow when passing a Date/Time query parameter.

What’s happening:

• The same RaaS endpoint, credentials, and parameters return data when called from Postman

• The call from ServiceNow succeeds (HTTP 200) but returns no rows

• No errors are returned by Workday

ServiceNow configuration:

• Using REST Message / RESTMessageV2

• Base URL contains only the RaaS endpoint (no query parameters hard-coded)

• Query parameters are added via ServiceNow (not URL concatenation)

• Date/Time parameter passed raw in ISO 8601 format (letting ServiceNow handle encoding)
  Example:
  2025-12-24T00:00:00-05:00

• format=json passed as a query parameter

• Authentication: Basic Auth (same credentials used successfully in Postman)

• No custom headers beyond Authorization

Postman configuration:

• Same endpoint, credentials, and parameter names

• Same Date/Time value

• Returns expected data

What we’ve validated so far:

• Prompt name matches the Workday Web Service parameter name

• The report runs successfully in the Workday UI

• The integration user has access to the report

• No double-encoding of parameters

• Older dates (far in the past) still return no rows in ServiceNow

• Date-only values do not error but also return no data

Question:

Has anyone experienced ServiceNow modifying, dropping, or mis-encoding query parameters (especially Date/Time values) when using RESTMessageV2, causing Workday RaaS prompts to be ignored or evaluated incorrectly?

Additionally, is REST Message / RESTMessageV2 the recommended and expected approach in ServiceNow for calling external endpoints like Workday RaaS, or are there alternative outbound methods that handle Date/Time query parameters differently?

Any guidance or examples would be greatly appreciated.

Thank you!