> ## Documentation Index
> Fetch the complete documentation index at: https://docs.aseeflow.org/llms.txt
> Use this file to discover all available pages before exploring further.

# FEEL Engine

FEEL is part of the DMN specification and stands for "Friendly Enough Expression Language". You can
use it to evaluate expressions in a decision table.

You can use the Expression Language in the following DMN Notation Elements:

* [Input Expressions]
* [Input Entries]
* [Output Entries]
* [Literal Expressions]

This documentation covers everything integration-specific about the
[FEEL Scala Engine][] (opens external link) in the ASEE Flow DMN Engine. To see how FEEL can be used in other BPMN elements, visit: [Friendly Enough Expression Language guide](/user-guide/process-engine/expression-language/friendly-enough-expression-language)

[FEEL Scala Engine]: https://github.com/camunda/feel-scala

[input entries]: /reference/dmn/decision-table/rule#input-entry-condition

[Input Expressions]: /reference/dmn/decision-table/input#input-expression

[Output Entries]: /reference/dmn/decision-table/rule#output-entry-conclusion

[Literal Expressions]: /reference/dmn/decision-literal-expression

## In this section

* [**FEEL Engine Type Handling**](/user-guide/dmn-engine/feel/type-handling) — How FEEL handles types.
* [**FEEL Engine Custom Functions**](/user-guide/dmn-engine/feel/custom-functions) — Register custom FEEL functions.
* [**FEEL Engine Spin Integration**](/user-guide/dmn-engine/feel/spin-integration) — Use Spin within FEEL.
* [**FEEL Engine Legacy Behavior**](/user-guide/dmn-engine/feel/legacy-behavior) — Enable legacy FEEL behavior.