How do you implement retry logic in Mule flows?

• A. Use Try scope with a single attempt.
• B. Use Until Successful scope or a configured retry strategy to retry a block with max retries and delay.
• C. Hard-code a delay loop outside Mule.
• D. Use DataWeave to retry transforms.

Answer: (B)

Retrying a block of a flow when a transient error occurs is the idea behind reliable Mule flows. The best way to implement this is to wrap the potentially failing part in an Until Successful scope, or apply a retry strategy to that block. Until Successful is designed for this use: it automatically re-enters the enclosed processors until they complete successfully, with configurable max retries and a delay between attempts. This lets you tolerate temporary issues (like a flaky network or a momentary database lock) without writing custom looping logic, and it stops after the defined limit to surface the error for proper handling if the issue persists. A configured retry strategy offers the same deterministic, declarative control over how many times to retry and how long to wait between attempts, and can be applied to multiple components consistently. Hard-coding a delay loop outside Mule is brittle and adds maintenance overhead, while using a Try scope with a single attempt provides no retry at all. DataWeave is for data transformation, not flow control or retry behavior.