Best Practices

1. Security

• Always use HTTPS in production
• Store credentials securely (use environment variables or secret managers)
• Implement proper authentication and authorization
• Rotate credentials regularly

2. Error Handling

• Implement retry logic with exponential backoff
• Log all API interactions for troubleshooting
• Handle all possible status codes gracefully
• Provide meaningful error messages to users

3. Performance

• Use connection pooling for multiple requests
• Implement request timeouts
• Monitor API response times
• Cache process template information when possible

4. Testing

• Test with both JSON and XML formats
• Verify correlation set behavior
• Test error scenarios (invalid data, missing parameters)
• Load test for production readiness

5. Documentation

• Document your process interfaces clearly
• Maintain API endpoint inventory
• Version your process templates
• Keep integration documentation updated

Monitoring and Troubleshooting

If the sendMessage call does not behave as expected, first check the request URL, headers, payload, HTTP status code, and response body.

For deeper analysis, enable tracing on the BAW server. Trace can help identify issues such as an incorrect portType, wrong operation name, payload mapping problems, or correlation mismatches.

Example trace specification:

com.ibm.bpm.rest.*=all
com.ibm.ws.webcontainer.*=all

After enabling trace, reproduce the problem, review the server logs, and then reduce or disable tracing because detailed trace can generate large log files.

• Issue 1: 409 Conflict

A 409 Conflict usually means that BAW received the message, but could not deliver it to the process in the expected way. This can happen if the target process template is stopped, if the process is not currently waiting at the expected Receive activity, or if correlation values do not match an existing running instance.

What to check

• • • the process template is started and deployed correctly
    • the process instance is waiting for the expected message
    • the correlation field is present in the payload
    • the correlation value matches the correct running instance
• Issue 2: Wrapper element such as EVENTMSG

In some environments, the request body may need to include a wrapper element because the deployed message structure expects it. This is not simply a client preference. It depends on how the input message was defined in the interface and how BAW maps the incoming payload to that message.

What to check

• • • the expected input message structure in the WSDL or XSD
    • whether the root JSON or XML element must be wrapped
    • whether the payload matches the message part name used by the interface
    • If a wrapper element is required, structure the payload exactly as defined by the deployed message model.
• Issue 3: Port type not found

This error usually means the portType value in the REST request does not exactly match the WSDL definition used by the BPEL process. Even a small difference in the namespace or local name can prevent BAW from resolving the target operation.

What to check

• • • the exact QName from the WSDL
    • the namespace URI
    • the local port type name
    • the operation name associated with that port type

When troubleshooting, always compare the REST request values directly with the deployed WSDL rather than entering them manually from memory.

Real-World Use Cases

The sendMessage API can be used in many integration scenarios where an external system needs to start or continue a BPEL process. A few common examples are:

• Order processing
  Start an order fulfillment process when an order is submitted from a web or mobile application.
• Customer onboarding
  Trigger an onboarding process when a new customer is created in a portal or CRM system.