In Salesforce Winter '27, External Services supports an empty OpenAPI schema object for an any-type request body. Flow serializes a record variable to JSON and sends it directly to the endpoint without an Apex class or a Transform element for that step. release note
The request can combine an any-type body with typed query, path, and header parameters. Flows can keep working when the data schema changes, but the external API must handle its own payload validation.
Before replacing body-construction logic
Confirm Data 360 is provisioned and the External Services definition will use API 68.0 or later. Then create the definition with an empty schema object for the request body.
Test a Flow record variable against the endpoint’s contract. Confirm the endpoint’s expected response to each payload change.
| Recommended test | Expected outcome to document |
|---|---|
| Add a field to the payload | Whether the endpoint accepts, ignores, or rejects the additional field under its contract. |
| Change a field’s value type | Whether the endpoint accepts the value or rejects it under its type-validation rules. |
Before removing existing Apex or a Transform element, check whether it does more than construct the request body. Have the external API owner confirm endpoint-side payload validation before removing existing validation. Assess application logic separately and retain anything the new call does not replace. Resolve contract-test failures before adoption. Successful JSON serialization alone does not establish that the endpoint will accept the payload.