You can use the following methods to perform fault handling:

Use a boundary event to catch faults.
Use output fields or a Throw step to return faults.

For example, create a process that accepts two numbers as input and performs four mathematical operations on them: addition, subtraction, division, and multiplication.

If you do not enable fault handling and invoke the process with the numbers 5 and 0, you see an HTTP 500 error. This is because of division by zero. In addition, you do not see a result the addition, subtraction, or multiplication results.

If you enable fault handling and invoke the process with the numbers 5 and 0, you see the following response:

{"Sum":"5", "Difference": "5", "Product":"0"; "Quotient": "Fault"}