Outbound REST authentication

  • Release version: Australia
  • Updated March 12, 2026
  • 1 minute to read

    • Outbound REST messages support multiple types of authentication.

    Different web service providers may require a specific type of authentication. Outbound REST supports the following authentication formats.
    • Basic authentication using a username and password
    • OAuth 2.0 using an OAuth provider and profile
    • Mutual authentication using protocol profiles

    Limitations of RESTMessage

    The following capabilities are supported in the REST Step (IntegrationHub) but are not available in the RESTMessageV2 scripted API:

    Table 1. Limitations of RESTMessage
    Limitation Description
    Mutual authentication on MID Server mTLS (client certificate authentication) is not supported when routing REST calls through a MID Server. Mutual authentication via RESTMessageV2 is supported only for direct instance calls.
    Multipart with attachments Multipart Content-Type requests for sending file attachments are not supported.
    Custom authentication (Authentication Algorithm) Custom authentication profiles using the Authentication Algorithm framework are not available.
    AWS authentication (Authentication Algorithm) AWS Signature Version 4 authentication via the Authentication Algorithm framework is not supported.
    Retry policy for outbound calls Built-in configurable retry policies for automatic retries on transient failures are not available. Custom retry logic must be implemented in script.
    Note:
    You can use the REST Step on IntegrationHub for these capabilities.

    Overriding REST authentication

    You can define authentication for a REST message, or individually for each HTTP method. HTTP methods inherit authentication from their parent REST message record when the HTTP method Authentication type is Inherit from parent, which is the default value.

    You can disable authentication for a specific HTTP method by setting the Authentication type field to No authentication, or specify authentication that is different from the parent REST message by selecting basic auth or OAuth.

    Authentication requirements

    Authentication requirement for REST Outbound are as follows:

    • Outbound REST supports mutual authentication only when using basic authentication. Mutual authentication is not available with OAuth 2.0.
    • OAuth 2.0 can be used only with messages that are not configured to use a MID Server. You cannot send OAuth 2.0 authenticated messages through a MID Server. Also, mutual authentication is not supported with MID Server.
    • When scripting new REST messages configured with authentication you must use the RESTMessageV2 API. The legacy RESTMessage APIs do not support current authentication formats.
    • AWS credentials or any other custom authentication are supported only with the REST step, not with the RestMessage API.