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Expression Component Reference

MuleSoft recommends against deployments to Mule 3.8. Standard Support for this version ended on November 16, 2018, and Mule 3.8 will reach its End of Life on November 16, 2021, when Extended Support ends.

This component evaluates an expression. It accepts either a user-defined expression or a reference to a file.

Minimum requirement: The expression or file to evaluate.


Unlike the Expression Transformer, the expression component does not replace the message payload with the results of expression evaluation. See the Implementing Business Logic subsection in Mule Expression Language MEL for an example illustrating the use of an expression component.

  • Display name: Type a useful name for the transformer to display in your flow (optional)

  • Expression: The expression to evaluate

  • File: Absolute path of the file containing the expression to evaluate. Click the ellipsis (…​) button next to the File field to select the file with a browser

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